analisis laju korosi dan lifetime pipa astm a105 …repository.ppns.ac.id/2338/1/0815040061 -...

TUGAS AKHIR (608502A)

ANALISIS LAJU KOROSI DAN LIFETIME PIPA ASTM A105 DENGAN PERBANDINGAN INHIBITOR NaNO2 DAN Na2CrO4 TITRIES ADISTANTRIA MARIAMI NRP. 0815040061 DOSEN PEMBIMBING : BAMBANG ANTOKO, S.T., M.T SUBAGIO SO’IM, S.T., M.T

PROGRAM STUDI TEKNIK PERPIPAAN JURUSAN TEKNIK PERMESINAN KAPAL POLITEKNIK PERKAPALAN NEGERI SURABAYA SURABAYA 2019

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TUGAS AKHIR (608502A)

ANALISIS LAJU KOROSI DAN LIFETIME PIPA ASTM A105 DENGAN PERBANDINGAN INHIBITOR NaNO2 DAN Na2CrO4

Titries Adistantria Mariami NRP. 0815040061

DOSEN PEMBIMBING: BAMBANG ANTOKO, S.T., M.T SUBAGIO SO’IM, S.T., M.T

PROGRAM STUDI TEKNIK PERPIPAAN JURUSAN TEKNIK PERMESINAN KAPAL POLITEKNIK PERKAPALAN NEGERI SURABAYA SURABAYA 2019

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(Halaman ini sengaja dikosongkan)

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KATA PENGANTAR

Puji syukur penulis panjatkan kepada Allah SWT atas segala rahmat, ridho,

dan hidayah-Nya penulis dapat menyelesaikan penyusunan Tugas Akhir ini dengan

baik dan lancar. Penulis juga mengucapkan shalawat serta salam semoga senantiasa

terlimpah curahkan kepada Nabi Muhammad SAW, kepada keluarganya, para

sahabat yang telah memberikan teladan bagi seluruh umat manusia.

Tugas akhir yang berjudul “Analisis Laju Korosi dan Lifetime Pipa

ASTM A105 dengan Perbandingan Inhibitor NaNO2 dan Na2CrO4” ini disusun

sebagai salah satu persyaratan untuk menyelesaikan pendidikan kuliah di Program

Studi Teknik Perpipaan.

Penulis menyadari penyelesaian dan penyusunan Tugas Akhir ini tidak

terlepas dari kerjasama, bantuan, dan bimbingan dari berbagai pihak, sehingga

penulis menyampaikan terimakasih yang sebesar-besarnya kepada :

1. Kedua orang tua, kakak-kakak, dan keponakan yang telah memberikan banyak

kasih sayang, nasihat hidup, doa, dukungan moril serta materil, dan segalanya

bagi penulis.

2. Bapak Ir. Eko Julianto, M.T., FRINA. selaku Direktur Politeknik Perkapalan

Negeri Surabaya.

3. Bapak George Endri Kusuma, S.T., M.Sc. Eng. sebagai Ketua Jurusan Teknik

Permesinan Kapal, Politeknik Perkapalan Negeri Surabaya.

4. Bapak Dimas Endro Witjonarko, S.T., M.T. sebagai Ketua Program Studi

Teknik Perpipaan, Politeknik Perkapalan Negeri Surabaya.

5. Bapak Bambang Antoko, S.T., M.T sebagai dosen pembimbing I yang telah

memberikan banyak bimbingan dan pengarahan selama pengerjaan tugas akhir

dengan sabar.

6. Bapak Subagio So’im, S.T., M.T. sebagai dosen pembimbing II yang telah

memberikan banyak bimbingan dan pengarahan selama pengerjaan tugas akhir

dengan sabar.

7. Seluruh staf pengajar Program Studi Teknik Perpipaan yang telah memberikan

banyak ilmu kepada penulis selama masa perkuliahan.

viii

8. Bapak Pendik yang telah mengajarkan dan memberikan tempat untuk

melakukan penelitian juga arahan dalam pengerjaan Tugas Akhir.

9. Kepada sahabat tersayang satu kos Gita Arsy Jayanti, Ayu Safitri, Hanik Indah

dan Diana yang selalu menemani, memberikan dukungan, dan selalu

memberikan lelucon dan semangat kepada penulis.

10. Kepada 9 Ciwi Srikandi yang selalu membantu, memberikan dukungan dan

semangat kepada penulis.

11. Teman-teman seperjuangan Teknik Perpipaan angkatan 2015 yang telah

memberikan banyak bantuan selama pengerjaan tugas akhir dan kehidupan

perkuliahan selama di PPNS.

12. Seluruh kakak senior Teknik Perpipaan angkatan 2013 dan 2014 yang telah

memberikan banyak bantuan selama pengerjaan tugas akhir.

13. Kepada Park Chanyeol, Kim Jongdae, dan semua member EXO yang telah

membantu menyemangati penulis dengan lagunya.

14. Seluruh pihak yang tidak dapat disebutkan satu-persatu yang telah banyak

membantu.

Penulis menyadari bahwa Tugas Akhir ini masih jauh dari kesempurnaan.

Harapan penulis dapat mendapatkan kritik atau saran yang membangun agar

penelitian yang telah dilakukan menjadi lebih baik lagi. Semoga Tugas akhir ini

bermanfaat bagi pembaca.

Surabaya, 21 Agustus 2019

Penulis

ix

ANALISIS LAJU KOROSI DAN LIFETIME PIPA ASTM A105

DENGAN PERBANDINGAN INHIBITOR NaNO2 Titries Adistantria Mariami

ABSTRAK

Korosi adalah permasalahan yang sering muncul pada dunia industri yang

menyebabkan penurunan kualitas material. Apabila korosi tidak dicegah dari awal

maka kerugian yang cukup parah akan timbul. Salah satu permasalahan korosi yang

ada di pabrik pengolahan minyak dan margarin daerah Gresik adalah Internal

Corrosion. Kerak yang menggumpal di bagian dalam pipa ASTM A105 berdiameter

1 inch berumur kurang lebih 2 tahun. Penelitian ini menggunakan metode

Immersion Test yang digunakan untuk mengetahui laju korosi dan remaining life

pipa ASTM A105 dengan perhitungan weight loss dan membandingkan Inhibitor

NaNO2 dan Na2CrO4. Pengujian dilakukan dengan variasi konsentrasi NaCl sebesar

1000 ppm, 1100 ppm, dan 1200 ppm. Variasi konsentrasi Inhibitor sebesar 0 ppm,

150 ppm, 250 ppm, dan 350 ppm. Hasil pengujian yang telah dilakukan

menunjukkan bahwa nilai korosi terendah menggunakan inhibitor NaNO2 dengan

konsentrasi NaCl 1200 ppm yakni sebesar 0.021817 mm/y. Sedangkan inhibitor

Na2CrO4 memiliki laju korosi terendah sebesar 0.023999 mm/y. Untuk nilai

efisiensi inhibitor tertinggi adalah inhibitor NaNO2 350 ppm pada konsentrasi NaCl

1200 ppm sebesar 0.537%. Dan hasil perhitungan remaining life untuk inhibitor

NaNO2 sebesar 150.73 tahun dan 137.37 tahun untuk inhibitor Na2CrO4. Jadi

metode perlindungan korosi terbaik bagi material ASTM A105 adalah

menggunakan inhibitor NaNO2 karena memiliki nilai laju korosi terendah dan usia

pakai yang jauh lebih lama.

Kata kunci : ASTM A105, inhibitor, Immersion Test, laju korosi, lifetime

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CORROSION RATE AND LIFETIME ANALYSIS ON ASTM A105

WITH NaNO2 AND Na2CrO4 INHIBITOR COMPARISON

Titries Adistantria Mariami

ABSTRACT

Corrosion are the most common problem that happens in the industry causing

material quality reduction. If corrosion was not prevented from the beginning, there

will be a serious loss because of leaking that affects on the decreasing of material

lifetime. One of the corrosion problem in an oil and margarine processing factory

in Gresik is Internal Corrosion. Caused by a lump of crust inside the ASTM A105

pipe with 1 inch diameter with 2 years of lifetime. This research used immersion

test method to determine the corrosion rate and lifetime of ASTM A105 pipe with

weight loss calculation and compared NaNO2 and Na2CrO4 inhibitors. The testing

used NaCl concentrate variation of 1000 ppm, 1100 ppm, 1200 ppm. Inhibitor

concentrate variation are 0 ppm, 150 ppm, 250 ppm, and 350 ppm. Test results

shows that the lowest corrosion rate used 350ppm NaNO2 inhibitor with 1200 ppm

NaCl concentrate with the value of 0,021817 mm/y. Meanwhile Na2CrO4 inhibitor

have the lowest corrosion value of 0.023999 mm/y. For the highest inhibitor

efficiency value are 350 ppm NaNO2 inhibitor on 1200 ppm NaCl concentrate with

the value of 0.537%. And the remaining life calculation for NaNO2 inhibitor are

150.73 years and 137.37 years for Na2CrO4 inhibitor. So the best corrosion

protection method for ASTM A105 material are using NaNO2 inhibitor because it

have the lowest corrosion rate value and much longer service life.

Keywords : ASTM A105, Inhibitor, Immersion Test, Corrosion Rate, Lifetime

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DAFTAR ISI

LEMBAR PENGESAHAN ............................................................................... iii

PERNYATAAN BEBAS PLAGIAT ................................................................. v

KATA PENGANTAR ...................................................................................... vii

ABSTRAK ......................................................................................................... ix

ABSTRACT........................................................................................................ xi

DAFTAR ISI ................................................................................................... xiii

DAFTAR TABEL .......................................................................................... xvii

DAFTAR GAMBAR ....................................................................................... xix

BAB 1 PENDAHULUAN................................................................................... 1

1.1 Latar Belakang ................................................................................ 1

1.2 Rumusan Masalah ........................................................................... 2

1.3 Tujuan Penelitian ............................................................................ 2

1.4 Manfaat Penelitian........................................................................... 3

1.5 Batasan Masalah .............................................................................. 3

BAB 2 TINJAUAN PUSTAKA ......................................................................... 5

2.1 Korosi ............................................................................................... 5

2.2 Jenis – Jenis Korosi ......................................................................... 6

2.2.1 Korosi Merata (Uniform Attack) ..................................................... 6

2.2.2 Korosi Galvanik (Galvanic Corrosion) ........................................... 7

2.2.3 Korosi Selektif (Selective Leaching Corrosion) .............................. 8

2.2.4 Korosi Sumuran (Pitting Corrosion) ............................................... 8

2.2.5 Korosi Celah (Crevice Corrosion) .................................................. 9

2.2.6 Korosi Batas Butir (Intergranular Corrosion) ............................... 10

2.2.7 Korosi Retak Tegangan (Stress Corrosion Cracking) .................... 11

2.2.8 Korosi Erosi (Errosion Corrosion)................................................ 12

2.3 Pengendalian Korosi ...................................................................... 13

2.3.1 Faktor Metalurgi ........................................................................... 13

2.3.2 Faktor Lingkungan ....................................................................... 14

2.5 Inhibitor ......................................................................................... 17

2.5.1 Inhibitor Anodik ........................................................................... 18

2.5.2 Inhibitor Katodik .......................................................................... 20

2.6 Material ASTM A105 ..................................................................... 20

xiv

2.7 Metode Weight Loss ....................................................................... 21

2.8 Remaining Life ............................................................................... 22

BAB 3 METODOLOGI PENELITIAN .......................................................... 25

3.1 Diagram Alir Penelitian ................................................................. 25

3.1.1 Tahap Identifikasi Awal ................................................................ 26

3.1.2 Tahap Tinjauan Pustaka ................................................................ 26

3.1.3 Tahap Pengumpulan Data ............................................................. 26

3.1.4 Tahap Pengolahan Data dan Analisa ............................................. 27

3.2 Jadwal Penelitian ........................................................................... 28

3.2.1 Waktu Penelitian........................................................................... 28

3.2.2 Tempat Penelitian ......................................................................... 29

BAB 4 HASIL DAN PEMBAHASAN ............................................................. 31

4.1 Tahap Pelaksanaan Eksperimen ................................................... 31

4.2 Analisa Hasil Uji Korosi dengan Pengujian Immersion Test ........ 35

4.2.1 Perhitungan Luas Permukaan Spesimen ........................................ 35

4.2.2 Perhitungan Corrosion Rate .......................................................... 37

4.2.3 Perhitungan Efisiensi Inhibitor ...................................................... 42

4.2.3 Perhitungan Minimum Thickness ................................................... 44

4.2.4 Perhitungan Remaining Life .......................................................... 44

4.3 Analisa dan Pembahasan ............................................................... 48

4.3.1 Analisa Hasil Pengujian Laju Korosi Konsentrasi NaCl 1000 ppm 48

4.3.2 Analisa Hasil Pengujian Laju Korosi Konsentrasi NaCl 1100 ppm 49

4.3.3 Analisa Laju Korosi Konsentrasi NaCl 1200 ppm ......................... 50

4.3.4 Analisa Hasil Perhitungan Efisiensi Inhibitor Konsentrasi NaCl

1000 ppm ............................................................................................... 51


1100 ppm ............................................................................................... 52


1200 ppm ............................................................................................... 52

4.3.7 Analisa Hasil Perhitungan Remaining Life Konsentrasi NaCl 1000

ppm ..................................................................................................... 53


ppm ..................................................................................................... 54


ppm ..................................................................................................... 55

BAB 5 KESIMPULAN DAN SARAN ............................................................. 57

xv

5.1 Kesimpulan .................................................................................... 57

5.2 Saran .............................................................................................. 57

DAFTAR PUSTAKA ....................................................................................... 59

LAMPIRAN A ASTM G1

LAMPIRAN B ASTM G31-72

LAMPIRAN C API 570

LAMPIRAN D ASME B31.3

LAMPIRAN E ASTM A105

LAMPIRAN F HANDBOOK OF CORROSION ENGINEERING

LAMPIRAN G DATA IMMERSION TEST

LAMPIRAN H MSDS NaNO2

LAMPIRAN I MSDS Na2CrO4 LAMPIRAN J MSDS NaCl LAMPIRAN K DATA PERUSAHAAN LAMPIRAN L REKOMENDASI SIDANG

LAMPIRAN M DAFTAR KEMAJUAN TUGAS AKHIR LAMPIRAN N FOTO PENGUJIAN

LAMPIRAN O BIODATA DIRI

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DAFTAR TABEL

Tabel 2.1 Chemical requirements A105 ........................................................ 21

Tabel 3.1 Parameter perhitungan Immersion test .......................................... 27

Tabel 4.1 Perhitungan Luas Permukaan ........................................................ 36

Tabel 4.2 Hasil perhitungan laju korosi konsentrasi NaCl 1000 ppm ............. 39



Tabel 4.5 Hasil perhitungan efisiensi inhibitor konsentrasi NaCl 1200 ppm .. 42



Tabel 4.8 Parameter pendukung perhitungan Minimum Thickness ................. 44

Tabel 4.9 Hasil perhitungan Remaining Life konsentrasi NaCl 1000 ppm ..... 45

Tabel 4.10 Hasil perhitungan Remaining Life konsentrasi NaCl 1000 ppm ... 46

Tabel 4.11 Hasil perhitungan Remaining Life konsentrasi NaCl 1000 ppm ... 47

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xix

DAFTAR GAMBAR

Gambar 1.1 Internal Corrosion .................................................................. 1

Gambar 2.1 Korosi Merata ......................................................................... 6

Gambar 2 2 Korosi Galvanik ...................................................................... 7

Gambar 2.3 Korosi Selektif pada Pipa ........................................................ 8

Gambar 2.4 Korosi Sumuran ...................................................................... 9

Gambar 2.5 Korosi Celah ........................................................................... 10

Gambar 2. 6 Korosi Intergranular .............................................................. 11

Gambar 2.7 Korosi Retak Tegangan ........................................................... 12

Gambar 2. 8 Korosi Erosi ........................................................................... 12

Gambar 2.9 Pengaruh konsentrasi material terhadap laju korosi .................. 14

Gambar 2.10 Pengaruh temperatur terhadap laju korosi .............................. 15

Gambar 2.11 Pengaruh persentase komposisi kimia terhadap laju korosi .... 16

Gambar 2.12 Kerangka Konseptual ............................................................ 23

Gambar 3.1 Diagram Alir Penelitian .......................................................... 25

Gambar 4.1 Spesimen Pengujian Laju Korosi ............................................ 31

Gambar 4.2 Proses Perendaman Spesimen .................................................. 32

Gambar 4.3 Proses Penimbangan Spesimen ............................................... 32

Gambar 4.4 Proses Pembuatan Larutan Inhibitor ......................................... 33

Gambar 4.5 Proses Perendaman dengan Larutan Inhibitor ........................... 33

Gambar 4.6 Pengeringan Spesimen ............................................................ 34

Gambar 4.7 Proses Pembuatan Larutan NaCl ............................................. 34

Gambar 4.8 Perendaman Spesimen dengan Larutan NaCl .......................... 35

Gambar 4.9 Proses Penimbangan Setelah Pengujian ................................... 35

Gambar 4.10 Keterangan Dimensi Spesimen .............................................. 36

Gambar 4.11 Grafik Laju Korosi Konsentrasi NaCl 1000 ppm ................... 47

Gambar 4.12 Grafik Laju Korosi Konsentrasi NaCl 1100 ppm .................... 48

Gambar 4.13 Grafik Laju Korosi Konsentrasi NaCl 1200 ppm .................... 49

Gambar 4.14 Grafik Efisiensi Inhibitor Konsentrasi NaCl 1000 ppm .......... 50

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Gambar 4.15 Grafik Efisiensi Inhibitor Konsentrasi NaCl 1100 ppm........... 51

Gambar 4.16 Grafik Efisiensi Inhibitor Konsentrasi NaCl 1200 ppm........... 52

Gambar 4.17 Grafik Remaining Life Konsentrasi NaCl 1000 ppm .............. 53



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BAB 1

PENDAHULUAN

1

BAB 1

PENDAHULUAN

1.1 Latar Belakang

Dalam dunia industri khususnya di bidang material, korosi adalah salah satu

dari banyaknya permasalahan yang sering mucul. Korosi sendiri merupakan

penurunan mutu logam akibat reaksi dengan lingkungan yang bersifat spontan oleh

karena itu korosi tidak bisa dihentikan secara total namun bisa untuk memperlambat

proses korosi. Dalam dunia industri kerugian yang disebabkan oleh korosi adalah

penurunan kekuatan material dan biaya perbaikan yang tidak sedikit. Apabila korosi

tidak dicegah dari awal, maka kerugian yang cukup parah akan timbul seperti

kerugian akibat kebocoran dan mengakibatkan lifetime material berkurang .

Gambar 1.1 Internal Corrosion

(Sumber: Data Perusahaan)

Contoh korosi yang muncul pada pabrik produksi minyak dan margarin di

daerah gresik adalah adanya internal corrosion pada pipa ASTM A105 berukuran 1

inch. Menurut ASME B31.3 yakni process piping pipa dengan material tersebut

termasuk ke dalam golongan Carbon Steel. Pada gambar 1.1 yang terlihat korosi

akibat air payau tergolong sangat parah karena adanya gumpalan pada pipa bagian

dalam. Adanya perluasan pipa pada area produksi sejauh 6 meter menjadi alasan

bagaimana pipa tersebut terpotong pada bagian elbow. Masalah ini telah

menyebabkan berkurangnya efisiensi aliran fluida pada pipa tersebut. Namun, pada

kenyataan dilapangan dengan umur pipa yang masih dua tahun pemakaian sangat

2

tidak wajar mengalami korosi yang begitu parah. Sehingga, untuk mengatasi

masalah pada pipa tersebut kontraktor harus mengganti pipa yang telah terkorosi

dengan pipa yang baru sepanjang perluasan bangunan.

Untuk meminimalisir terjadinya korosi yang lebih parah, maka perlu

dilakukan penelitian lebih lanjut dengan perhitungan laju korosi dan lifetime dengan

metode yang sesuai untuk mencegah terjadinya korosi. Penggunaan metode yang

sesuai dengan permasalahan ini setelah penggantian pipa dilakukan dengan

penambahan inhibitor korosi, sehingga didapat metode proteksi terbaik untuk

diterapkan sesuai kondisi di lapangan. Penelitian ini akan dijadikan referensi untuk

kasus yang serupa.

1.2 Rumusan Masalah

Perumusan masalah dari penelitian ini adalah sebagai berikut:

1. Bagaimana perbandingan laju korosi pada material ASTM A105 dengan

menggunakan inhibitor NaNO2 dan Na2CrO4?

2. Bagaimana perbandingan lifetime pada material ASTM A105 dengan

menggunakan inhibitor NaNO2 dan Na2CrO4?

3. Bagaimana penggunaan inhibitor yang paling efektif ditinjau dari segi laju

korosi dan lifetime?

1.3 Tujuan Penelitian

Tujuan dari penelitian ini adalah sebagai berikut:

1. Mengetahui perbandingan laju korosi pada material ASTM A105 dengan

menggunakan inhibitor NaNO2 dan Na2CrO4.

2. Mengetahui perbandingan lifetime pada material ASTM A105 dengan

menggunakan inhibitor NaNO2 dan Na2CrO4

3. Mengetahui penggunaan inhibitor yang paling efektif ditinjau dari segi laju

korosi dan lifetime.

3

1.4 Manfaat Penelitian

Adapun manfaat yang dapat diambil dari penelitian ini adalah sebagai berikut :

1. Bagi mahasiswa

a. Mendapat tambahan referensi untuk mengetahui nilai laju korosi, lifetime

dan nilai ekonomis untuk pergantian material atau media penambahan

inhibitor.

b. Sebagai tugas akhir yang merupakan salah satu syarat kelulusan program

studi D-4 Teknik Perpipaan.

2. Bagi institusi

Sebagai tambahan literatur yang akan dapat diakses oleh semua civitas

akademika PPNS.

3. Bagi perusahaan

Laporan tugas akhir ini bisa dijadikan rujukan bagi perusahaan dalam usahanya

mengetahui cara untuk mencegah korosi melalui pergantian material atau

media penambahan inhibitor.

1.5 Batasan Masalah

Batasan masalah pada penelitian ini adalah sebagai berikut :

1. Material yang dianalisa dan diuji hanya tipe ASTM A105.

2. Perlindungan terhadap korosi menggunakan inhibitor NaNO2 dan Na2CrO4.

3. Variasi Inhibitor 0 ppm, 150 ppm, 250 ppm, 350 ppm

4. Variasi konsentrasi NaCl 1000 ppm, 1100 ppm, dan 1200 ppm

5. Kondisi fluida pada saat penelitian adalah statis

6. Standart pengujian mengacu pada ASTM G-31.

7. Waktu pengujian adalah 30 hari atau 720 jam.

8. Pengujian menggunakan metode Immersion Test dan perhitungan laju

menggunakan metode weight loss.

9. Temperatur yang digunakan dalam penelitian ini adalah temperatur ruang.

4


1

BAB 2

TINJAUAN PUSTAKA

5

BAB 2

TINJAUAN PUSTAKA

2.1 Korosi

Bagi sebagian besar orang, korosi dapat di artikan sebagai karat (rust). Korosi

adalah perusakan atau penurunan mutu dari material akibat bereaksi dengan

lingkungan (Fontana, 1986). Korosi adalah kerusakan material yang umumnya

logam yang ditandai dengan adanya pengurangan ketebalan pada material yang

secara umum disebabkan oleh reaksi material dengan lingkungan di sekitarnya

(Damayanti,2018). Salah satu jenis utama yang mudah terkena korosi adalah sistem

perpipaan. Korosi dapat diartikan sebagai perusakan suatu material (terutama

logam karena bereaksi dengan lingkungan) sebagian logam akan menjadi

oksida,sulfide,atau hasil reaksi lain yang dapat larut dalam lingkungannya

(Suherman,1987). Korosi adalah peristiwa perusakan atau penurunan kualitas

logam karena reaksi kimia yang terjadi antara logam dengan zat zat yang ada di

lingkungannya sehingga menghasilkan senyawa-senyawa yang tidak dikehendaki

(Khuncoro,2018). Korosi dapat terjadi pada semua logam , terutama yang

berhubungan dengan udara atau cairan yang korosif. Mesin-mesin yang

bersinggungan langsung dengan air atau cairan lain yang korosif akan mudah

terserang korosi lebih-lebih jika mesin tersebut berhubungan langsung dengan air

secara terus menerus (Atmadja, 2010). Korosi didefinisikan sebagai penghancuran

paksa zat seperti logam dan bahan bangunan mineral media sekitarnya, yang

biasanya cair. Ini biasanya dimulai pada permukaan dan disebabkan oleh kimia dan

dalam kasus logam, reaksi elektrokimia. Kehancuran kemudian dapat menyebar

kebagian dalam materi (Ganesya, 2018).

Menurut dari berbagai jurnal dan buku, beberapa pengertian tersebut

memiliki definisi yang serupa. Jadi beberapa definisi tersebut dapat disimpulkan

arti dari korosi adalah sebuah kerusakan atau penurunan kualitas material yang

umumnya terjadi pada logam. Disebabkan oleh senyawa - senyawa kimia dan faktor

lingkungan. ditandai dengan munculnya lapisan merah kecoklatan dan atau

pengurangan ketebalan material.

6

2.2 Jenis – Jenis Korosi

2.2.1 Korosi Merata (Uniform Attack)

Korosi merata atau Uniform Attack adalah Pada korosi jenis korosi

menyeluruh, seluruh permukaan logam yang terekspose dengan lingkungan,

terkorosi secara merata (Furqan, 2013). Jenis korosi ini mengakibatkan

rusaknya konstruksi secara total. Mekanisme Uniform Corrosion adalah

dengan distribusi seragam dari reaktan katodik atas seluruh permukaan logam

yang terekspose. Pada lingkungan asam (pH < 7), terjadi reduksi ion

hidrogen dan pada lingkungan basa (pH > 7) atau netral (pH = 7), terjadi

reduksi oksigen. Kedua berlangsung secara "seragam" dan tidak ada lokasi

preferensial atau lokasi untuk reaksi katodik atau anodik. Katoda dan anoda

terletak secara acak dan bergantian dengan waktu. Hasil akhirnya adalah

hilangnya kurang lebih yang seragam dimensi. Contoh material yg

mengalami korosi merata ada pada Gambar 2.1.

Gambar 2.1 Korosi merata

(http://krisnayanarina.blogspot.com)

Korosi jenis ini bisa dicegah dengan cara :

1. Diberi lapis lindung yang mengandung inhibitor seperti gemuk.

2. Untuk lambung kapal diberi proteksi katodik

3. Pemeliharaan material yang tepat

4. Untuk jangka pemakain yang lebih panjang diberi logam berpaduan tembaga

0,4%

http://krisnayanarina.blogspot.com/2014/09/jenis-jenis-korosi.html

7

2.2.2 Korosi Galvanik (Galvanic Corrosion)

Korosi Galvanik atau Galvanic Corrosion adalah jenis korosi yang

terjadi ketika dua macam logam yang berbeda berkontak secara langsung

dalam media korosif (Furqan, 2013). Mekanisme korosi galvanik : korosi ini

terjadi karena proses elektro kimiawi dua macam metal yang berbeda

potensial dihubungkan langsung di dalam elektrolit sama. Dimana electron

mengalir dari metal kurang mulia (Anodik) menuju metal yang lebih mulia

(Katodik), akibatnya metal yang kurang mulia berubah menjadi ion – ion

positif karena kehilangan electron. Ion-ion positif metal bereaksi dengan ion

negatif yang berada di dalam elektrolit menjadi garam metal. Contoh material

yang mengalami korosi galvanik ada pada Gambar 2.2. Metode-metode yang

dilakukan dalam pengendalian korosi ini adalah:

1. Menekan terjadinya reaksi kimia atau elektrokimianya seperti reaksi

anoda dan katoda

2. Mengisolasi logam dari lingkungannya

3. Mengurangi ion hydrogen di dalam lingkungan yang di kenal dengan

mineralisasi

4. Mengurangi oksigen yang larut dalam air

5. Mencegah kontak dari dua material yang tidak sejenis

6. Memilih logam-logam yang memiliki unsure-unsur yang berdekatan

7. Mencegah celah atau menutup celah

8. Mengadakan proteksi katodik, dengan menempelkan anoda umpan.

Gambar 2 2 Korosi galvanik

(http://krisnayanarina.blogspot.com)

http://krisnayanarina.blogspot.com/2014/09/jenis-jenis-korosi.html

8

2.2.3 Korosi Selektif (Selective Leaching Corrosion)

Selective leaching adalah korosi selektif dari satu atau lebih komponen

dari paduan larutan padat. Hal ini juga disebut pemisahan, pelarutan selektif

atau serangan selektif (Furqan, 2013). Contoh dealloying umum adalah

dekarburisasi, decobaltification, denickelification, dezincification, dan

graphitic corrosion. Mekanisme selective leaching adalah logam yang

berbeda dan paduan memiliki potensial yang berbeda (atau potensial korosi)

pada elektrolit yang sama. Paduan modern mengandung sejumlah unsur

paduan berbeda yang menunjukkan potensial korosi yang berbeda. Beda

potensial antara elemen paduan menjadi kekuatan pendorong untuk serangan

preferensial yang lebih "aktif" pada elemen dalam paduan tersebut. Contoh

material yg mengalami korosi selektif ada pada Gambar 2.3.

Gambar 2.3 Korosi selektif pada pipa

(http://m10mechanicalengineering.blogspot.co.id)

2.2.4 Korosi Sumuran (Pitting Corrosion)

Korosi sumuran adalah korosi lokal dari permukaan logam yang

dibatasi pada satu titik atau area kecil, dan membentukn bentuk rongga

(Furqan, 2013). Korosi sumuran adalah salah satu bentuk yang paling

merusak dari korosi. Contoh material yg mengalami korosi sumuran ada

pada Gambar 2.4. Mekanisme Pitting Corrosion adalah untuk material

bebas cacat, korosi sumuran disebabkan oleh lingkungan kimia yang

mungkin berisi spesies unsur kimia agresif seperti klorida. Klorida sangat

merusak lapisan pasif (oksida) sehingga pitting dapat terjadi pada dudukan

oksida. Lingkungan juga dapat mengatur perbedaan sel aerasi (tetesan air

http://m10mechanicalengineering.blogspot.co.id/

9

pada permukaan baja, misalnya) dan pitting dapat dimulai di lokasi anodik

(pusat tetesan air). Cara pengendalian korosi sumuran adalah sebagai

berikut:

1. Hindari permukaan logam dari goresan

2. Perhalus permukaan logam.

3. Menghindari komposisi material dari berbagai jenis logam.

Gambar 2.4 Korosi sumuran

(http://m10mechanicalengineering.blogspot.com)

2.2.5 Korosi Celah (Crevice Corrosion)

Korosi celah mengacu pada serangan lokal pada permukaan logam

pada, atau berbatasan langsung dengan, kesenjangan atau celah antara dua

permukaan bergabung (Furqan, 2013). Kesenjangan atau celah dapat

terbentuk antara dua logam atau logam dan bahan non-logam. Di luar

kesenjangan atau tanpa celah, kedua logam yang tahan terhadap korosi.

Kerusakan yang disebabkan oleh korosi celah biasanya dibatasi pada satu

logam di wilayah lokal dalam atau dekat dengan permukaan yang bergabung.

Contoh material yg mengalami korosi celah ada pada Gambar 2.5.

Mekanisme Crevice Corrosion adalah dimulai oleh perbedaan konsentrasi

beberapa kandungan kimia, biasanya oksigen, yang membentuk konsentrasi

sel elektrokimia (perbedaan sel aerasi dalam kasus oksigen). Di luar dari celah

(katoda), kandungan oksigen dan pH lebih tinggi - tetapi klorida lebih rendah.

Cara pengendalian korosi celah adalah sebagai berikut:

http://m10mechanicalengineering.blogspot.com/

10

1. Hindari pemakaian sambungan paku keeling atau baut, gunakan

sambungan las,

2. Gunakan gasket non-absorbing,

3. Usahakan menghindari daerah dengan aliran udara.

Gambar 2.5 Korosi celah

(http://yayanlutfi6812.blogspot.com)

2.2.6 Korosi Batas Butir (Intergranular Corrosion)

Intergranular corrosion kadang-kadang juga disebut "intercrystalline korosi"

atau "korosi interdendritik". Dengan adanya tegangan tarik, retak dapat terjadi

sepanjang batas butir dan jenis korosi ini sering disebut "intergranular retak korosi

tegangan (IGSCC)" atau hanya "intergranular stress corrosion cracking" (Furqan,

2013). Contoh material yg mengalami korosi intergranular ada pada Gambar 2.6.

Mekanisme intergranular corrosion adalah jenis serangan ini diawali dari beda

potensial dalam komposisi, seperti sampel inti “coring” biasa ditemui dalam paduan

casting. Pengendapan pada batas butir, terutama kromium karbida dalam baja tahan

karat, merupakan mekanisme yang diakui dan diterima dalam korosi intergranular.

Cara pengendalian korosi batas butir adalah:

1. Turunkan kadar karbon dibawah 0,03%

2. Tambahkan paduan yang dapat mengikat karbon

3. Pendinginan cepat dari temperatur tinggi

4. Pelarutan karbida melalui pemanasan

5. Hindari pengelasan.

http://yayanlutfi6812.blogspot.com/2014/11/korosi-celah.html

11

Gambar 2. 6 Korosi intergranular

(http://m10mechanicalengineering.blogspot.com)

2.2.7 Korosi Retak Tegangan (Stress Corrosion Cracking)

Korosi retak tegangan (SCC) adalah proses retak yang memerlukan aksi

secara bersamaan dari bahan perusak (karat) dan berkelanjutan dengan tegangan

Tarik (Furqan, 2013). Ini tidak termasuk pengurangan bagian yang terkorosi akibat

gagal oleh patahan cepat. Hal ini juga termasuk intercrystalline atau transkristalin

korosi, yang dapat menghancurkan paduan tanpa tegangan yang diberkan atau

tegangan sisa. Retak korosi tegangan dapat terjadi dalam kombinasi dengan

penggetasan hidrogen. Contoh material yg mengalami korosi retak tegangan ada

pada Gambar 2.7. Mekanisme SCC adalah terjadi akibat adanya hubungan dari 3

faktor komponen, yaitu bahan rentan terhadap korosi, adanya larutan elektrolit

(lingkungan), adanya tegangan. Sebagai contoh, tembaga dan paduan rentan

terhadap senyawa amonia, baja ringan rentan terhadap larutan alkali dan baja tahan

karat rentan terhadap klorida. Cara pengendalian korosi tegangan adalah:

1. Turunkan besarnya tegangan

2. Turunkan tegangan sisa termal

3. Kurangi beban luar atau perbesar area potongan

4. Penggunaan inhibitor.

http://m10mechanicalengineering.blogspot.com/

12

Gambar 2.7 Korosi retak tegangan


2.2.8 Korosi Erosi (Errosion Corrosion)

Erosi Korosi mengacu pada tindakan gabungan yang melibatkan erosi dan

korosi di hadapan cairan korosif yang bergerak atau komponen logam yang

bergerak melalui cairan korosif, yang menyebabkan percepatan terdegradasinya

suatu logam (Furqan, 2013). Contoh material yg mengalami korosi erosi terjadi

pada blade ada pada Gambar 2.8. Mekanisme erosion corrosion: efek mekanik

aliran atau kecepatan fluida dikombinasikan dengan aksi cairan korosif

menyebabkan percepatan hilangnya dari logam. Tahap awal melibatkan

penghapusan mekanik film pelindung logam dan kemudian korosi logam telanjang

oleh cairan korosif yang mengalir. Proses siklus ini sampai pelubangan komponen

terjadi.

Cara pengendalian korosi erosi adalah:

1. Menghindari partikel abrasive pada fluida

2. Mengurangi kecepatan aliran fluida.

Gambar 2.8 Korosi erosi



13

2.3 Pengendalian Korosi

Ada beberapa faktor yang mempengaruhi suatu logam dapat terkorosi dan

kecepatan laju korosi suatu logam. Suatu logam yang sama belum tentu mengalami

kasus korosi yang sama pula pada lingkungan yang berbeda. Begitu juga dua logam

pada kondisi lingkungan yang sama tetapi jenis materialnya berbeda, belum tentu

mengalami korosi yanga sama. Terdapat dua faktor yang dapat mempengaruhi

korosi suatu logam, yaitu faktor metalurgi dan faktor lingkungan.

2.3.1 Faktor Metalurgi

Faktor metalurgi adalah pada material itu sendiri. Apakah suatu logam

dapat tahan terhadap korosi, berapa kecepatan korosi yang dapat terjadi pada

suatu kondisi, jenis korosi apa yang paling mudah terjadi, dan lingkungan apa

yang dapat menyebabkan terkorosi, ditentukan dari faktor – faktor metarulugi

tersebut (Firdausi, 2012). Yang termasuk dalam faktor metalurgi antara lain :

1. Jenis logam dan paduannya

Pada lingkungan tertentu, suatu logam dapat tahan tehadap

korosi.Sebagai contoh, aluminium dapat membentuk lapisan pasif pada

lingkungan tanah dan air biasa, sedangkan Fe, Zn, dan beberapa logam

lainnya dapat dengan mudah terkorosi.

2. Morfologi dan homogenitas

Bila suatu paduan memiliki elemen paduan yang tidak homogen, maka

paduan tersebut akan memiliki karakteristik ketahanan korosi yang

berbeda-beda pada tiap daerahnya.

3. Perlakuan panas

Logam yang di-heat treatment akan mengalami perubahan struktur kristal

atau perubahan fasa. Sebagai contoh perlakuan panas pada temperatur

500-800 oC terhadap baja tahan karat akan menyebabkan terbentuknya

endapan krom karbida pada batas butir. Hal ini dapat menyebabkan

terjadinya korosi intergranular pada baja tersebut. Selain itu, beberapa

proses heat treatment menghasilkan tegangan sisa. Bila tegangan sisa

tesebut tidak dihilangkan, maka dapat memicu terjadinya korosi retak

tegang.

14

4. Sifat mampu fabrikasi dan pemesinan

Merupakan suatu kemampuan material untuk menghasilkan sifat yang

baik setelah proses fabrikasi dan pemesinan. Bila suatu logam setelah

fabrikasi memiliki tegangan sisa atau endapan inklusi maka

memudahkan terjadinya retak.

2.3.2 Faktor Lingkungan

Menurut (Firdausi, 2012), faktor-faktor lingkungan yang dapat

mempengaruhi korosi antara lain:

1. Konsentrasi

Konsentrasi dari elektrolit atau kandungan oksigen akan mempengaruhi

kecepatan korosi yang terjadi. Pengaruh konsentrasi elektrolit terlihat

pada laju korosi yang berbeda dari besi yang tercelup dalam H2O4 encer

atau pekat, dimana pada larutan encer, Fe akan mudah larut dibandingkan

dalam H2SO4 pekat. Pengaruh konsentrasi terhadap laju korosi dapat

dilihat pada Gambar 2.10 berikut.

Gambar 2.9 Pengaruh konsentrasi material terhadap laju korosi

( http://www.agungfirdausi.my.id)

Suatu logam yang berada pada lingkungan dengan kandungan O2 yang

berbeda akan terbagi menjadi dua bagian yaitu katodik dan anodik.

Daerah anodik terbentuk pada media dengan konsentrasi O2 yang rendah

dan katodik terbentuk pada media dengan konsentrasi O2 yang tinggi.

15

2. Temperatur

Pada lingkungan temperatur tinggi, laju korosi yang terjadi lebih

tinggi dibandingkan dengan temperatur rendah, karena pada temperatur

tinggi kinetika reaksi kimia akan meningkat. Gambar 2.11 berikut

menunjukkan pengaruh temperatur terhadap laju korosi pada Fe.

Semakin tinggi temperatur, maka laju korosi akan semakin meningkat,

namun menurunkan kelarutan oksigen, sehingga pada suatu sistem

terbuka, diatas suhu 800˚C, laju korosi akan mengalami penurunan

karena oksigen akan keluar sedangkan pada suatu sistem tertutup, laju

korosi akan terus menigkat karena adanya oksigen yang terlarut.

Gambar 2.10 Pengaruh temperatur terhadap laju korosi

( http://www.agungfirdausi.my.id)

3. Komposisi kimia

Ion-ion tertentu yang terlarut di dalam lingkungan dapat

mengakibatkan jenis korosi yang berbeda-beda. Misalkan antara air laut

dan air tanah memiliki sifat korosif yang berbeda dimana air laut

mengandung ion klor yang sangat reaktif mengakibatkan korosi. Gambar

2.11 berikut menunjukkan pengaruh komposisi elemen paduan terhadap

ketahanan korosi terhadap paduan tembaga.

16

Gambar 2.11 Pengaruh persentase komposisi kimia terhadap laju korosi

(http://agungfirdausi.my.id)

5. Gas, cair atau padat

Kandungan kimia di medium cair, gas atau padat berbeda-beda.

Misalkan pada gas, bila lingkungan mengandung gas asam, maka korosi

akan mudah terjadi (contohnya pada pabrik pupuk). Kecepatan dan

penanganan korosi ketiga medium tersebut juga dapat berbeda-beda.

Untuk korosi di udara, proteksi katodik tidak dapat dilakukan, sedangkan

ada medium cair dan padat memungkinkan untuk dilakukan proteksi

katodik.

6. Kondisi biologis

Mikroorganisme sepert bakteri dan jamur dapat menyebabkan

terjadinya korosi mikrobial terutama sekali pada material yang terletak

di tanah. Keberadaan mikroorganisme sangat mempengaruhi konsentrasi

oksigen yang mempengaruhi kecepatan korosi pada suatu material.

Faktor-faktor metalurgi dan lingkungan harus dievaluasi secara integral.

Dalam suatu industri, sering diterapkan beberapa jenis logam dalam

suatu kondisi lingkungan, atau sebaliknya satu jenis logam berada dalam

beberapa jenis kondisi lingkungan. Kondisi yang paling rumit adalah

beberapa jenis logam berada pada beberapa jenis lingkungan.

17

2.4 Prinsip Pengendalian Korosi

Korosi adalah proses penurunan kualitas sifat material (logam) oleh reaksi

elektrokimia karena berinteraksi dengan lingkungan. Korosi tidak dapat dihindari

lagi, namun korosi dapat dicegah dan di kendalikan, sehingga struktur ataupun

komponen mempunyai masa pakai yang lebih panjang. Pengendalian terhadap

korosi bertujuan untuk mengatur laju korosi, sehingga perkembangannya tetap

berada dalam rentang tertentu atau dapat digunakan untuk mengetahui batas umur

pada suatu struktur. (Pribadi, 2018)

Proteksi terhadap korosi atau lebih tepat disebut pengendalian terhadap

korosi dapat digolongkan menjadi empat golongan besar yaitu :

1. Pengendalian korosi dengan mengubah jenis logam dan desain.

2. Pengendalian korosi dengan mengubah media korosif.

3. Pengendalian korosi dengan cara mengubah potensial (tegangan) antara

logam/media korosif.

4. Pengendalain korosi dengan pelapisan permukaan.

2.5 Inhibitor

Inhibitor merupakan zat yang akan ditambahkan ke lingkungan dengan

konsentrasi yang relatif rendah, dan memiliki pengaruh untuk menurunkan

laju korosi (Pratiwi & Setiawan, 2015). Umumnya inhibitor berasal dari

senyawa-senyawa organik dan anorganik yang mengandung gugus-gugus

yang memiliki pasangan elektron bebas seperti nitri, pospat, kromat dan lain-

lain. Berdasarkan bahan dasarnya, maka inhibitor dibedakan sebagai berikut :

1. Inhibitor organik menghambat korosi dengan cara teradsorpsi pada

permukaan logam. Inhibitor ini terbuat dari bahan organik yang bisa

diperoleh dari hewan maupun tumbuhan. Pada umumnya senyawa-

senyawa organik yang dapat digunakan adalah senyawa-senyawa yang

mampu membentuk senyawa komples baik kompleks yang terlarut maun

terendap. Untuk itu diperlukan adanya gugus-gugus fungsi yang

mengandung atom-atom yang dapat membentuk ikatan kovalen

terkoordinasi, misalnya gugus amine, tio, fosfo, eter dan senyawa lainnya.

18

2. Inhibitor anorganik dapat menghibisi material logam baik secara anodik

maupun katodik karena memiliki gugus aktif. Inhibitro ini terdiri dari

beberapa senyawa anorganik antara lain : fosfat, kromat, dikromat,

silikat, borat molibdat dan senyawa lainnya. Senyawa-senyawa tersebut

sangat berguna dalam melindungi material logam dari korosi, namun

inhibitor ini memiliki kelemahan yaitu bersifat toksik.

2.5.1 Inhibitor Anodik

Inhibitor jenis ini bekerja dengan mengubah sifat permukaan

logam menjadi pasif. Cara kerja inhibitor ini ada dua cara yaitu (1)

membetuk perlindungan tanpa membutuhkan oksigen dan inhibitor ini

berbasis nitrat, nitrit dan kromat dan (2) membentuk perlindungan

dengan membutuhkan oksigen dan berbasis posfat (PO4-3), tungstat

(Wo4-2) dan molibdat (MoO4-2). Inhibitor jenis ini b.iasa digunakan

pada recirculation-cooling systems, rectrifier dan cooling tower.

(Utomo, 2015). Berikut ini merupakan contoh dari inhibitor anodik :

1. Ortofosfat

Penambahan ortofosfat (Na2HPO4) ke dalam air akan

menaikkan alkalinitas, tetapi juga efektif dalam pembentukan film

protektif jika air mengandung kesadahan kalsium yang cukup. Film

protektif ini terutama mengandung kalsium karbonat dan besi oksida

serta sedikit fosfat. Hal ini menjelaskan bahwa fosfat di alam air

lunak tidak berpengaruh jika tidak ada penambahan soda.

2. Benzoat

Benzoat merupakan inhibitor non oksidator dan

dikelompokkan sebagai inhibitor anodik. Inhibitor in tidak termasuk

berbahaya, karena dengan konsentrasi yang cukup kecil mempunyai

pengaruh yang tidak merugikan. Inhibitor ini, biasanya digunakan

bersama dengan natrium nitrit untuk memproteksi bagian mesin

terhadap aliran air.

3. Silikat

Natrium silikat mempunyai komposisi Na2O.2SiO2 dan

digunakan sebagai inhibitor dalam air. Silikat berfungsi ganda,yaitu

19

sebagian silikat bertindak sebagai alkali dan sebagian lagi berfungsi

sebagai inhibitor anodik. Inhibitor ini dalam air berupa koloid dengan

tipe (mSiO2.nSiO3)2n- yang terbentuk oleh hidrolisis dalam larutan

aqueous. Kemungkinan anion ini bermigrasi secara elektroforetik

menuju permukaan anoda, Kemungkinan anion ini bermigrasi secara

elektroforetik menuju permukaan anoda.

4. Kromat

Senyawa kromat seperti Na2CrO4 merupakan inhibitor

oksidator, sehingga penambahan inhibitor ini membentuk lapisan

pasif, yang mengandung Cr2O3. Inhibitor kromat merupakan

inhibitor yang sangat efektif dalam air dan sangat cocok untuk

memproteksi logam baja dan tembaga (Cu).

5. Nitrit

Ortofosfat dan Silikat merupakan inhibitor yang efektif dalam

air yang mengandung kesadahan kalsium (air sadah). Dalam air

lunak, inhibitor yang efektif adalah inhibitor nitrit dan kromat. Nitrit

merupakan oksidator, sehingga produk korosinya merupakan

senyawa dengan bilangan oksidasi tinggi, karena senyawa ini

mempunyai kelarutan lebih rendah dan membentuk film protektif

lebih mudah. Biasanya, penggunaan inhibitor ini dicampur dengan

inhibitor lain seperti benzoate dan fosfat.

Di pihak lain inhibitor anodik dianggap berbahaya karena

penambahan inhibitor yang terlalu sedikit tidak akan berhasil

menghilangkan bagian- bagian yang bersifat katoda dan justru akan

meningkatkan laju korosi. Peningkatan serang anodik yang bersifat

lokal disebabkan oleh :

1. Tidak memadainya inhibitor yang ditambahkan ke dalam

elektrolit

2. Pengenceran elektrolit sesudah ditambahkan inhibitor

20

3. Tingginya konsentrasi ion-ion depolarisasi seperti sulfat atau

klorida yang ditambahkan justru akan mengurangi kedayagunaan

inhibitor dalam larutan

4. Inhibitor gagal menembus dead legs dalam sistem.

2.5.2 Inhibitor Katodik

Inhibitor katodik bekerja dengan menghambat reaksi katodik

suatu logam dan membentuk presipitat di wilayah katoda yang dapat

meningkatkan impedasi permukaan sekaligus membatasi difusi

pereduksi untuk melindungi logam tersebut. Reaksi yang terjadi:

Pembentukan H2:2H++2 e→H

Reduksi gas O2: O2+4H++4 e→2 H2O

Karena bagi suatu sel korosi terjadi reaksi reduksi dan reaksi oksidasi

dengan kecepatan yang sama, maka apabila reaksi reduksi (pada katoda)

dihambat akan menghambat pula reaksi oksidasi (pada anoda). Inilah

yang menjadi pedoman pertama di dalam usaha menghambat korosi

logam dalam medium air atau medium asam.(Utomo, 2015)

2.6 Material ASTM A105

ASTM A105 merupaka material pipa yang dilapisi oleh zinc (galvanized),

Paduan baja yang terlibat adalah baja rendah karbon, mangan dan silikon yang

mirip dengan AISI 1330, tetapi dengan kandungan mangan yang lebih rendah.

ASTM A105 memiliki nilai minimum tensile 485 MPa (70 ksi) dan memiliki nilai

minimum yield strength 248 MPa (36 ksi). Berikut untuk chemical requirements

ASTM A105 ada pada Tabel 2.1.

21

Tabel 2.1 Chemical Requirements A105

(Sumber: ASTM A105)

2.7 Metode Weight Loss

Metode kehilangan berat adalah metode perhitungan laju korosi dengan

mengukur pengurangan berat akibat korosi yang terjadi. Metode ini menggunakan

jangka waktu penelitian hingga mendapatkan jumlah pengurangan berat akibat

terjadinya korosi. Standart yang digunakan untuk mendapatkan jumlah kehilangan

berat korosi yaitu mengacu pada (ASTM G1-03 (2004). Standards Practice for

Preparing, Cleaning, and Evaluating Corrosion Test Specimen, American Society

for Testing Material, U.S.A) maka digunakan rumus sebagai berikut :

Cr = (𝐾.𝑊)

(𝐷.𝐴.𝑇) ................................................................................................... (2.1)

Dimana :

Cr : Corrosion Rate (mm/y)

K : Konstanta (8,76 x 104 )

(ASTM G1-03 (2004). Standard Practice for Preparing, Cleaning, and

Evaluating Corrosion Test Specimen, American Society for Testing Material,

U.S.A)

D : Density of specimen (7,86 gr/cm3)

(ASTM G1-03 (2004). Standard Practice for Preparing, Cleaning, and

Evaluating Corrosion Test Specimen, American Society for Testing Material,

U.S.A)

W : Weight loss (gr)

22

A : Area of specimen (cm2)

T : Exposure time (hour)

Dari persamaan diatas setelah diketahui laju korosi dari material yang diuji

selanjutnya menghitung persentase proteksi yang dilakukan inhibitor yang

digunakan, menggunakan persamaan dari Handbook of Corrosion Engineers

Chapter 10 Corrosion Inhibitor :

Einh = 𝐶𝑅0− 𝐶𝑅1

𝐶𝑅0 x 100% .................................................................................. (2.2)

Dimana :

E : Efisiensi Inhibitor Korosi (%)

CR0 : Kecepatan laju korosi tanpa inhibitor (mm/y)

CR1 : Kecepatan laju korosi dengan menggunakan inhibitor (mm/y)

2.8 Remaining Life

Perhitungan Remaining Life menggunakan referensi dari ASME B31.3 dan API 570

sebagai persamaan 2.3 dan 2.4 berikut :

tm= 𝑃(𝑑+2𝑐)

2[(𝑆𝐸𝑊−𝑃(1−𝑌)] ........................................................................................ (2.3)

tr = 𝑡𝑎𝑐𝑐 − 𝑡𝑚

𝐶𝑟 ................................................................................................. (2.4)

Dimana :

tr : Remaining life (years)

tacc : Thickness actual (mm)

Cr : Corrosion Rate (mm/y)

tm : Thickness Minimum Required (mm)

P : Design Pressure (psig)

d : Inside Diameter (mm)

c : Mechanical Allowance (mm)

S : Allowable stress value for material (psi)

E : Joint eficiency (-)

Y : Coefficient (-)

W : Weld Joint Strength (-)

23

Gambar 2.12 Kerangka Konseptual

Samuel Hermawan (2017) Analisa Pengaruh Penambahan Inhibitor Terhadap Laju Korosi Material pada Sistem Pipa Pendingin Fresh Water KM. Satya Kencana

Dhanang Bagus K. (2018) Perbandingan Inhibitor NaNO3 dan

K2CrO4 pada Material Stainless

Steel 316L Terhadap Laju Korosi Fluida Sulfuric Acid PT. Petrokimia Gresik

Tugas Akhir (2019) Analisis Laju Korosi dan

Lifetime pipa ASTM A105 dengan perbandingan Inhibitor NaNO2 dan

Na2CrO4 1 Jenis Material yang digunakan

CS A53 Gr. B

2 Inhibitor yang digunakan

Na2CrO4

3 Variasi Konsentrasi Inhibitor

yang digunakan adalah 0 ppm,

150 ppm, 250 ppm, dan 350

ppm

4 Metode yang digunakan adalah

metode Immersion test untuk

mengetahui laju korosi dengan

perhitungan weight loss

5 Variasi temperature yang

digunakan 60oC, 70oC, 80oC,

dan 90oC

1 Jenis Material yang digunakan

SS 316L


NaNO3 dan K2CrO4



150 ppm, 250 ppm, dan 350 ppm






digunakan 45oC, 55oC, dan 65oC

1 Jenis Material yang

digunakan ASTM A105


NaNO2 dan Na2CrO4


yang digunakan adalah 0

ppm, 150 ppm, 250 ppm, dan

350 ppm

4 Metode yang digunakan

adalah metode Immersion

test untuk mengetahui laju

korosi dengan perhitungan

weight loss

5 Variasi konsentrasi NaCl

yang digunakan 1000 ppm,

1100 ppm, 1200 ppm

Agung Wibowo (2016) Analisa Pengaruh Penambahan Inhibitor NaNO2 Terhadap Laju

Korosi Material CS A53 Grade B sch 40 di Sistem Pipa Pendingin Fresh Water KM. Satya Kencana

1 Jenis Material yang digunakan

CS A53 Gr. B


NaNO2



150 ppm, 250 ppm, dan 350

ppm






digunakan 60oC, 65oC, dan 70oC

24


BAB 3

METODOLOGI PENELITIAN

25

BAB 3

METODOLOGI PENELITIAN

3.1 Diagram Alir Penelitian

Berikut adalah diagram alir pada penelitian ini :

START

Identifikasi Awal dan

Perumusan Masalah

Studi Lapangan Studi Literatur

Pengumpulan Data Data Sekunder

Persiapan Pengujian

Menyiapkan

Peralatan

Pengujian

Menyiapkan

Inhibitor

Pembuatan Larutan

NaCl

Menyiapkan

Spesimen

Pengujian

Uji Korosi dengan

Immersion Test

Perhitungan Laju Korosi

dengan Metode Weight Loss

Analisa Teknis

Kesimpulan dan Saran

FINISH

Tahap Persiapan dan Pengumpulan Data

Tahap Pengolahan Data

Tahap Analisa dan Kesimpulan

Perhitungan Lifetime

Tahap Identifikasi Awal

Gambar 3.1 Diagram Alir Penelitian

26

3.1.1 Tahap Identifikasi Awal

Pada penelitian ini, permasalahan yang akan dibahas berkenaan dengan

pipa ASTM A105 berdiameter 1 inch yang mengalami internal corrosion

akibat air payau. Pemakaian pipa yang masih berumur dua tahun sangat

menjadi tidak wajar dan mengalami korosi yang sangat parah. Permasalahan

diketahui karena adanya perluasan pipa pada area produksi yang

mengharuskan pipa tersebut dipotong. Karena masalah tersebut maka

pergantian pipa harus dilakukan sepanjang 6 meter.

Penambahan Inhibitor diperlukan untuk mengatasi masalah Internal

Corrosion sebagai pelindung. Tipe inhibitor yang digunakan adalah NaNO2

dan Na2CrO4. Pengujian yang digunakan adalah Immersion Test dan

perhitungan laju korosinya menggunakan metode weight loss.

3.1.2 Tahap Tinjauan Pustaka

Tahap ini ditujukan untuk melakukan pengamatan di lapangan dan

mencari literatur yang mendukung permasalahan dalam penelitian ini.

Adapun isi dari tahap ini adalah sebagai berikut :

1. Studi Lapangan

Pada tahap ini dilakukan pengamatan secara tidak langsung terhadap

kondisi aktual di lapangan. Pengamatannya dilakukan dengan melihat

keadaan aktual lapangan yang diperoleh dari sumber terpercaya.

2. Studi Literatur

Pada tahap ini dilakukan pengumpulan teori yang berhubungan dengan

penelitian ini seperti teori korosi dan inhibitor yang akan digunakan

sebagai referensi dan acuan dalam mengerjakan tugas akhir.

3.1.3 Tahap Pengumpulan Data

Tahap pengumpulan data merupakan tahap untuk mengumpulkan data

– data yang berhubungan dengan permasalahan tersebut diatas. Data tersebut

dinamakan data sekunder. Data tersebut merupakan hasil analisa dan

interpretasi dari data primer. Namun, sumber lain menyebutkan bahwa data

sekunder adalah data penunjang atau data tambahan. Data sekunder yang

digunakan dalam penelitian ini meliputi data tanah dan Piping Data Sheet.

27

3.1.4 Tahap Pengolahan Data dan Analisa

Tahap pengolahan data merupakan tahap lanjutan dari penelitian

ini. Tahap ini terdiri dari langkah berikut :

1. Persiapan Pengujian

Persiapan untuk melakukan pengujian laju korosi :

1. Persiapan Spesimen Pengujian.

a. Material pipa ASTM A105 berdiameter luar sebesar 12,58

mm dan diameter dalam 10,24 mm dipotong dengan jumlah

sesuai dengan variasi konsentrasi dan direplikasi 2 kali

menjadi 42 buah spesimen.

b. Melakukan penimbangan massa dari spesimen dengan

timbangan digital sebelum dan sesudah proses pengujian. Hal

ini dilakukan untuk mendapatkan berat spesimen sebelum dan

sesudah pengujian.

2. Menyiapkan Peralatan Pengujian.

Peralatan yang perlu dipersiapkan saat pengujian :

Alat pengujian :

a. Gelas Plastik

b. Gelas Beaker

c. Jangka Sorong

d. Penggaris

e. Spidol

f. Gunting

g. Timbangan Digital

h. Kamera

3. Menyiapkan Inhibitor.

Menyiapkan larutan NaNO2 dan Na2CrO4 dengan variasi ppm

sebanyak 4 macam, yaitu 0 ppm, 150 ppm, 250 ppm, 350 ppm.

28

4. Pembuatan Larutan NaCl

Acuan yang digunakan untuk membuat larutan NaCl berdasarkan

data perusahaan. Variabel yang digunakan pada pembuatan larutan

NaCl berdasarkan referensi dari berbagai jurnal.

Cara pembuatan larutan NaCl dengan benar :

1. Timbang NaCl sesuai dengan kebutuhan konsentrasi

2. Siapkan aquades sebanyak 100 ml

3. Kemudian larutkan NaCl dengan aquades yang telah diukur di

dalam gelas Beaker, lalu aduk merata sampai larut

5. Perhitungan Laju Korosi

Tahap ini dilakukan untuk menentukan nilai laju korosi yang

berbeda karena adanya variasi inhibitor dan variasi konsentrasi

NaCl.

6. Perhitungan Lifetime

Tahap ini dilakukan karena setiap material memiliki lifetime dan

laju korosi yang berbeda.

Tabel 3.1 Parameter perhitungan Immersion Test

3.2 Jadwal Penelitian

3.2.1 Waktu Penelitian

Penentuan topik penelitian ini dilakukan pada bulan Desember-Januari

pada salah satu pabrik produksi minyak dan margarin di kabupaten Gresik.

Sedangkan untuk pengerjaan dan penyelesaiannya dimulai pada bulan Januari

NaCl 1000

ppm

NaCl 1100

ppm

NaCl 1200

ppm

Laju Korosi

(CR) Einh (%) Tm (mm)

Lifetime

(Years)

0

NaNO2 150 ppm

NaNO2 250 ppm

NaNO2 350 ppm

Na2CrO4 150 ppm

Na2CrO4 250 ppm

Na2CrO4 350 ppm

29

2019, diawali dengan pengajuan proposal sehingga total waktu

pengerjaannya ±6 bulan.

3.2.2 Tempat Penelitian

Tempat pelaksanaan penelitian dilakukan di salah satu pabrik produksi

minyak dan margarin di kabupaten Gresik, kampus Politeknik Perkapalan

Negeri Surabaya, dan Laboratorium D3 Teknik Kimia Institut Teknologi

Sepuluh November.

30


BAB 4

HASIL DAN PEMBAHASAN

31

BAB 4

HASIL DAN PEMBAHASAN

4.1 Tahap Pelaksanaan Eksperimen

Pelaksanaan eksperimen dilakukan dengan memvariasikan inhibitor NaNO2

dan Na2CrO4 dan larutan NaCl untuk pengujian laju korosinya. Eksperimen ini

melakukan pengambilan data sebanyak 2 kali, replikasi dilakukan untuk

mengurangi resiko cacat pada proses immersion dan agar data yang didapat lebih

akurat. Tahapan eksperimen sebagai berikut :

1. Persiapan spesimen yang diukur. Spesimen yang digunakan untuk

pengujian sebanyak 21 buah yang telah direplikasi 2 kali dengan outside

diameter 12,58 mm dan inside diameter 10,24 mm, untuk tinggi masing-

masing spesimen dapat dilihat pada tabel 4.1.

Gambar 4.1 Spesimen pengujian laju korosi (data pribadi)

2. Pembersihan material dari plug yang tertempel pada material.

Pembersihan menggunakan cairan HCl dapat dilihat pada gambar 4.2

32

Gambar 4.2 Proses perendaman spesimen (data pribadi)

3. Melakukan penimbangan spesimen sebelum proses perendaman dapat

dilihat pada gambar 4.3.

Gambar 4.3 Proses penimbangan spesimen (data pribadi)

4. Pembuatan larutan inhibitor NaNO2 dan Na2CrO4. Dengan masing-

masing variasi ppm sebanyak 4 macam, yaitu 0 ppm, 150 ppm, 250

ppm, dan 350 ppm.

33

Gambar 4.4 Proses pembuatan larutan inhibitor (data pribadi)

5. Setelah pembuatan larutan Inhibitor, dilakukan perendaman spesimen

dengan larutan inhibitor yang telah dibuat. Perendaman dilakukan

selama 336 jam.

Gambar 4.5 Proses perendaman dengan larutan inhibitor (data pribadi)

34

6. Proses pengambilan spesimen dan di tunggu sampai kering.

Gambar 4.6 Proses pengeringan spesimen (data pribadi)

7. Pembuatan larutan NaCl dengan variasi sebanyak 4 macam, yaitu

1000 ppm, 1100 ppm, dan 1200 ppm.

Gambar 4.7 Proses pembuatan larutan NaCl (data pribadi)

35

8. Setelah membuat larutan NaCl, dilakukan perendaman spesimen

dengan larutan NaCl yang telah dibuat. Perendaman dilakukan selama

336 jam.

Gambar 4.8 Proses perendaman spesimen dengan larutan NaCl (data pribadi)

9. Proses Penimbangan specimen setelah pengujian Immersion

Gambar 4.9 Proses penimbangan setelah pengujian (data pribadi)

4.2 Analisa Hasil Uji Korosi dengan Pengujian Immersion Test

Setelah perendaman menggunakan inhibitor dengan 2 variasi yaitu NaNO2

dan Na2CrO4 dilanjutkan dengan pengujian korosi menggunakan konsentrasi NaCl

dengan metode weight loss. Setiap spesimen dilakukan penimbangan sebelum dan

sesudah pengujian yang digunakan untuk melakukan perhitungan laju korosi.

4.2.1 Perhitungan Luas Permukaan Spesimen

Proses ini mengukur luas permukaan spesimen. Perhitungan luas

permukaan ditunjukkan dengan persamaan dibawah ini:

36

Gambar 4.10 Keterangan Dimensi Spesimen

Untuk spesimen kode 1a

Area of Specimen (A) = 𝜋 𝑥(((𝑂𝐷2−𝐼𝐷2)

2) +(𝐿𝑥(𝑂𝐷 + 𝐼𝐷)))

= 3.14 x (((12.582−10.242)

2) + (19.30 𝑥 (12.58 + 10.24)))

= 1466.773756 mm2

= 14.6677 cm2

Dimana :

OD = Outside Diameter = 12.58 mm

ID = Inside Diameter = 10.24 mm

L = Panjang Pipa = 19.30 mm

Hasil perhitungan untuk seluruh spesimen dapat dilihat di tabel 4.1

Tabel 4.1 Perhitungan Luas Permukaan

No. Spec

Outside Diameter (mm)

Inside

Diameter

(mm)

Panjang

Pipa

(mm)

Luas

Permukaan

(mm2)

Luas

Permukaan

(cm2)

1a 12.58 10.24 19.30 1466.773756 14.6677

1b 12.58 10.24 19.80 1502.601156 15.0260

2a 12.58 10.24 18.95 1441.694576 14.4169

2b 12.58 10.24 18.50 1409.449916 14.0945

3a 12.58 10.24 18.56 1413.749204 14.1375

3b 12.58 10.24 19.38 1472.50614 14.7251

4a 12.58 10.24 18.95 1441.694576 14.4169

37

4b 12.58 10.24 19.30 1466.773756 14.6677

5a 12.58 10.24 19.27 1464.624112 14.6462

5b 12.58 10.24 18.85 1434.529096 14.3453

6a 12.58 10.24 19.35 1470.356496 14.7036

6b 12.58 10.24 18.75 1427.363616 14.2736

7a 12.58 10.24 19.05 1448.860056 14.4886

7b 12.58 10.24 18.75 1427.363616 14.2736

8a 12.58 10.24 19.09 1451.726248 14.5173

8b 12.58 10.24 18.89 1437.395288 14.3740

9a 12.58 10.24 19.20 1459.608276 14.5961

9b 12.58 10.24 18.54 1412.316108 14.1232

10a 12.58 10.24 18.70 1423.780876 14.2378

10b 12.58 10.24 18.75 1427.363616 14.2736

11a 12.58 10.24 19.15 1456.025536 14.5603

11b 12.58 10.24 18.75 1427.363616 14.2736

12a 12.58 10.24 19.13 1454.59244 14.5459

12b 12.58 10.24 18.80 1430.946356 14.3095

13a 12.58 10.24 18.75 1427.363616 14.2736

13b 12.58 10.24 19.15 1456.025536 14.5603

14a 12.58 10.24 19.34 1469.639948 14.6964

14b 12.58 10.24 19.10 1452.442796 14.5244

15a 12.58 10.24 19.18 1458.17518 14.5818

15b 12.58 10.24 18.90 1438.111836 14.3811

16a 12.58 10.24 18.75 1427.363616 14.2736

16b 12.58 10.24 19.25 1463.191016 14.6319

17a 12.58 10.24 18.70 1423.780876 14.2378

17b 12.58 10.24 19.10 1452.442796 14.5244

18a 12.58 10.24 18.40 1402.284436 14.0228

18b 12.58 10.24 19.25 1463.191016 14.6319

19a 12.58 10.24 19.35 1470.356496 14.7036

19b 12.58 10.24 18.22 1389.386572 13.8939

20a 12.58 10.24 18.97 1443.127672 14.4313

20b 12.58 10.24 18.85 1434.529096 14.3453

21a 12.58 10.24 18.84 1433.812548 14.3381

21b 12.58 10.24 19.27 1464.624112 14.6462 Sumber: data pribadi

4.2.2 Perhitungan Corrosion Rate

Perhitungan laju korosi menggunakan metode weight loss menurut standart

ASTM G 31-72 2004 ada pada persamaan 2.1 yaitu sebagai berikut:

Corrosion Rate (Cr) = (𝐾.𝑊)

(𝐷.𝐴.𝑇)

38

Dimana :

K = Konstanta Korosi = 8.76 x104

W = Weight Loss = 0.016 gr

D = Massa Jenis Logam = 7.86 g/cm3

A = Luas Permukaan = 14.6677 cm2

T = Waktu pengujian = 336 jam

Spesimen kode 1a untuk konsetrasi NaCl 1000 ppm

Corrosion Rate (Cr) = (𝐾.𝑊)

(𝐷.𝐴.𝑇)

= 8.76 x 104 x 0.016

7.86 x 14.6677 x 336

= 0,036183 mm/y

Hasil perhitungan untuk seluruh spesimen dapat dilihat di tabel 4.2, tabel 4.3 dan

tabel 4.4

39

Tabel 4.2 Hasil perhitungan laju korosi konsentrasi NaCl 1000 ppm

Sumber: data pribadi

No. Spec Konsentrasi

Inhibitor

Konsentrasi

Nacl (ppm)

W awal

(g)

W akhir

(g)

Weight

Loss(g) T (jam) K A (cm2)

D

(g/cm3)

Cr

(mm/year) Keterangan

Rata-Rata

Cr

(mm/year)

1a 0 1000 1.775 1.759 0.016 336 87600 14.6677 7.86 0.036183 Replikasi 1 0.040166

1b 0 1000 1.832 1.812 0.020 336 87600 15.0260 7.86 0.044150 Replikasi 2

4a NaNO2 (150) 1000 1.615 1.603 0.012 336 87600 14.4169 7.86 0.027609 Replikasi 1 0.031896

4b NaNO2 (150) 1000 1.694 1.678 0.016 336 87600 14.6677 7.86 0.036183 Replikasi 2

7a NaNO2 (250) 1000 1.737 1.725 0.012 336 87600 14.4886 7.86 0.027472 Replikasi 1 0.026517

7b NaNO2 (250) 1000 1.844 1.833 0.011 336 87600 14.2736 7.86 0.025562 Replikasi 2

10a NaNO2 (350) 1000 1.720 1.709 0.011 336 87600 14.2378 7.86 0.025627 Replikasi 1 0.025594

10b NaNO2 (350) 1000 1.819 1.808 0.011 336 87600 14.2736 7.86 0.025562 Replikasi 2

13a Na2CrO4 (150) 1000 1.782 1.769 0.013 336 87600 14.2736 7.86 0.030210 Replikasi 1 0.033330

13b Na2CrO4 (150) 1000 1.716 1.700 0.016 336 87600 14.5603 7.86 0.036450 Replikasi 2





40




Inhibitor

Konsentrasi

Nacl

W awal

(g)

W akhir

(g)

Weight

Loss T (jam) K A (cm2)

D

(g/cm3)

Cr


Rata-Rata

Cr

(mm/year)

2a 0 1100 1.731 1.715 0.016 336 87600 14.4169 7.86 0.036812 Replikasi 1 0.044293

2b 0 1100 1.708 1.686 0.022 336 87600 14.0945 7.86 0.051774 Replikasi 2

5a NaNO2 (150) 1100 1.498 1.486 0.012 336 87600 14.6462 7.86 0.027177 Replikasi 1 0.032086

5b NaNO2 (150) 1100 1.784 1.768 0.016 336 87600 14.3453 7.86 0.036996 Replikasi 2

8a NaNO2 (250) 1100 1.820 1.808 0.012 336 87600 14.5173 7.86 0.027418 Replikasi 1 0.025247

8b NaNO2 (250) 1100 1.722 1.712 0.010 336 87600 14.3740 7.86 0.023076 Replikasi 2

11a NaNO2 (350) 1100 1.590 1.579 0.011 336 87600 14.5603 7.86 0.025059 Replikasi 1 0.024149

11b NaNO2 (350) 1100 1.651 1.641 0.010 336 87600 14.2736 7.86 0.023238 Replikasi 2







41




Inhibitor Konsentrasi

Nacl W awal

(g) W akhir (g)

Weight Loss

T (jam) K A (cm2) D (g/cm3) Cr


Rata-Rata Cr

(mm/year)

3a 0 1200 1.802 1.779 0.023 336 87600 14.1375 7.86 0.053963 Replikasi 1 0.047255

3b 0 1200 1.770 1.752 0.018 336 87600 14.7251 7.86 0.040547 Replikasi 2

6a NaNO2 (150) 1200 1.811 1.798 0.013 336 87600 14.7036 7.86 0.029327 Replikasi 1 0.034416

6b NaNO2 (150) 1200 1.716 1.699 0.017 336 87600 14.2736 7.86 0.039505 Replikasi 2

9a NaNO2 (250) 1200 1.779 1.765 0.014 336 87600 14.5961 7.86 0.031815 Replikasi 1 0.027651

9b NaNO2 (250) 1200 1.649 1.639 0.010 336 87600 14.1232 7.86 0.023486 Replikasi 2

12a NaNO2 (350) 1200 1.764 1.756 0.008 336 87600 14.5459 7.86 0.018243 Replikasi 1 0.021871

12b NaNO2 (350) 1200 1.699 1.688 0.011 336 87600 14.3095 7.86 0.025498 Replikasi 2







42

4.2.3 Perhitungan Efisiensi Inhibitor

Perhitungan efisiensi penggunaan inhibitor pada pengujian ini

dijelaskan pada perhitungan di bawah ini :

Diketahui :

Corrosion Rate (Variabel Terkontrol 0 ppm)

Corrosion Rate (Variabel Variasi 150 ppm, 250 ppm, 350 ppm)

Berikut ini perhitungan laju korosi dengan menggunakan metode kehilangan

berat :

Efisiensi Inhibitor (Einh) = 𝐶𝑅0−𝐶𝑅1

𝐶𝑅0 x 100%

Dimana :

CR0 : 0,0480 (mm/y)

CR1 : 0,0480 (mm/y)

Rata-rata dari spesimen kode 1a untuk konsetrasi NaCl 1000 ppm

Efisiensi Inhibitor (Einh) = 𝐶𝑅0−𝐶𝑅1

𝐶𝑅0 x 100%

= 0,036183−0,,036183

,036183 x 100%

= 0 %


tabel 4.7

Tabel 4.5 Hasil perhitungan efisiensi inhibitor konsentrasi NaCl 1000 ppm

No. Spec

Konsentrasi Inhibitor

Konsentrasi Nacl (ppm)

Weight Loss(g)

Cr (mm/year)

Keterangan Rata-Rata

Cr

(mm/year)

Efisiensi Inhibitor

(%)

1a 0 1000 0.016 0.036183 Replikasi 1 0.040166 0.000

1b 0 1000 0.020 0.044150 Replikasi 2

4a NaNO2 (150) 1000 0.012 0.027609 Replikasi 1 0.031896 0.206

4b NaNO2 (150) 1000 0.016 0.036183 Replikasi 2

7a NaNO2 (250) 1000 0.012 0.027472 Replikasi 1 0.026517 0.340

7b NaNO2 (250) 1000 0.011 0.025562 Replikasi 2

10a NaNO2 (350) 1000 0.011 0.025627 Replikasi 1 0.025594 0.363

10b NaNO2 (350) 1000 0.011 0.025562 Replikasi 2

13a Na2CrO4 (150) 1000 0.013 0.030210 Replikasi 1 0.033330 0.170

13b Na2CrO4 (150) 1000 0.016 0.036450 Replikasi 2



43





No. Spec



Weight Loss(g)

Cr (mm/year)

Keterangan

Rata-Rata

Cr (mm/year)

Efisiensi

Inhibitor (%)

2a 0 1100 0.016 0.036812 Replikasi 1 0.044293 0.000

2b 0 1100 0.022 0.051774 Replikasi 2

5a NaNO2 (150) 1100 0.012 0.027177 Replikasi 1 0.032086 0.276

5b NaNO2 (150) 1100 0.016 0.036996 Replikasi 2

8a NaNO2 (250) 1100 0.012 0.027418 Replikasi 1 0.025247 0.430

8b NaNO2 (250) 1100 0.010 0.023076 Replikasi 2

11a NaNO2 (350) 1100 0.011 0.025059 Replikasi 1 0.024149 0.455

11b NaNO2 (350) 1100 0.010 0.023238 Replikasi 2









No. Spec



Weight Loss(g)

Cr (mm/year)

Keterangan Rata-Rata

Cr (mm/year)

Efisiensi Inhibitor

(%)

3a 0 1200 0.023 0.053963 Replikasi 1 0.047255 0.000

3b 0 1200 0.018 0.040547 Replikasi 2

6a NaNO2 (150) 1200 0.013 0.029327 Replikasi 1 0.034416 0.272

6b NaNO2 (150) 1200 0.017 0.039505 Replikasi 2

9a NaNO2 (250) 1200 0.014 0.031815 Replikasi 1 0.027651 0.415

9b NaNO2 (250) 1200 0.010 0.023486 Replikasi 2

12a NaNO2 (350) 1200 0.008 0.018243 Replikasi 1 0.021871 0.537

12b NaNO2 (350) 1200 0.011 0.025498 Replikasi 2








44

4.2.3 Perhitungan Minimum Thickness

Terdapat beberapa parameter yang dibutuhkan untuk menghitung minimum

thickness. Perhitungan ini digunakan untuk mendukung perhitungan Remaining

Life. Parameter yang digunakan untuk perhitungan ini dapat dilihat pada tabel 4.8

Tabel 4.8 Parameter pendukung perhitungan Minimum Thickness

Berdasarkan ASME B31.3 2016 tentang Process Piping untuk menghitung nilai

thickness minimum menggunakan persamaan 2.3

Minimum Thickness (tm) = 𝑃(𝑑+2𝑐)

2[(𝑆𝐸𝑊−𝑃(1−𝑌)]

= 132.3(26.64+(2𝑥0.5))

2[(22000𝑥1𝑥1)−132.3(1−0.4)]

= 0.08341 mm

4.2.4 Perhitungan Remaining Life

Perhitungan Remaining Life menggunakan referensi dari standart API 570

ada pada persamaan 2.4 yaitu sebagai berikut:

Rata-rata dari spesimen kode 1a untuk konsetrasi NaCl 1000 ppm

Remaining Life (tm) = 𝑡𝑎𝑐𝑐−𝑡𝑚

𝐶𝑟

= 3.38−0.08341

0.040166

= 82.07 year


tabel 4.11

45

Tabel 4.9 Hasil perhitungan Remaining Life konsentrasi NaCl 1000 ppm

No.

Spec

Konsentrasi

Inhibitor

Konsentrasi

Nacl (ppm)

Weight

Loss(g)

Cr


Rata-Rata

Cr

(mm/year)

tacc

Design

Pressure

(psig)

Inside

Diameter

(mm)

Mechanica

l

Allowance

(c)

Allowable

Stress

Value for

Material

(S)

Quality

Factor

(E)

Coefficient

(Y)

Weld

Joint

Strength

(W)

tm Remaining

Life (year)

1a 0 1000 0.019 0.036183 Replikasi 1 0.040166 3.38 132.3 26.64 0.5 22000 1 0.4 1 0.08341 82.07

1b 0 1000 0.020 0.044150 Replikasi 2

4a NaNO2 (150) 1000 0.012 0.027609 Replikasi 1 0.031896 3.38 132.3 26.64 0.5 22000 1 0.4 1 0.08341 103.36

4b NaNO2 (150) 1000 0.016 0.036183 Replikasi 2

7a NaNO2 (250) 1000 0.012 0.027472 Replikasi 1 0.026517 3.38 132.3 26.64 0.5 22000 1 0.4 1 0.08341 124.32

7b NaNO2 (250) 1000 0.009 0.025562 Replikasi 2

10a NaNO2 (350) 1000 0.012 0.025627 Replikasi 1 0.025594 3.38 132.3 26.64 0.5 22000 1 0.4 1 0.08341 128.80

10b NaNO2 (350) 1000 0.004 0.025562 Replikasi 2

13a Na2CrO4 (150) 1000 0.013 0.030210 Replikasi 1 0.033330 3.38 132.3 26.64 0.5 22000 1 0.4 1 0.08341 98.91







46


No.

Spec

Konsentrasi

Inhibitor

Konsentrasi

Nacl (ppm)

Weight

Loss(g)

Cr


Rata-Rata

Cr

(mm/year)

tacc

Design

Pressure

(psig)

Inside

Diameter

(mm)

Mechanical

Allowance

(c)

Allowable

Stress

Value for

Material

(S)

Quality

Factor

(E)

Coefficient

(Y)

Weld

Joint

Strength

(W)

tm Remaining

Life (year)

2a 0 1100 0.021 0.036812 Replikasi 1 0.044293 3.38 132.3 26.64 0.5 22000 1 0.4 1 0.08341 74.43

2b 0 1100 0.020 0.051774 Replikasi 2

5a NaNO2 (150) 1100 0.012 0.027177 Replikasi 1 0.032086 3.38 132.3 26.64 0.5 22000 1 0.4 1 0.08341 102.74

5b NaNO2 (150) 1100 0.016 0.036996 Replikasi 2

8a NaNO2 (250) 1100 0.013 0.027418 Replikasi 1 0.025247 3.38 132.3 26.64 0.5 22000 1 0.4 1 0.08341 130.57

8b NaNO2 (250) 1100 0.010 0.023076 Replikasi 2

11a NaNO2 (350) 1100 0.011 0.025059 Replikasi 1 0.024149 3.38 132.3 26.64 0.5 22000 1 0.4 1 0.08341 136.51

11b NaNO2 (350) 1100 0.006 0.023238 Replikasi 2








47


No.

Spec

Konsentrasi

Inhibitor

Konsentrasi

Nacl (ppm)

Weight

Loss(g)

Cr


Rata-Rata Cr

(mm/year) tacc

Design

Pressure

(psig)

Inside

Diameter

(mm)

Mechanical

Allowance

(c)

Allowable

Stress Value

for Material

(S)

Quality

Factor

(E)

Coefficient

(Y)

Weld Joint

Strength

(W)

tm Remaining

Life (year)

3a 0 1200 0.014 0.053963 Replikasi 1 0.047255 3.38 132.3 26.64 0.5 22000 1 0.4 1 0.08341 69.76

3b 0 1200 0.014 0.040547 Replikasi 2

6a NaNO2 (150) 1200 0.012 0.029327 Replikasi 1 0.034416 3.38 132.3 26.64 0.5 22000 1 0.4 1 0.08341 95.79

6b NaNO2 (150) 1200 0.008 0.039505 Replikasi 2

9a NaNO2 (250) 1200 0.010 0.031815 Replikasi 1 0.027651 3.38 132.3 26.64 0.5 22000 1 0.4 1 0.08341 119.22

9b NaNO2 (250) 1200 0.004 0.023486 Replikasi 2

12a NaNO2 (350) 1200 0.008 0.018243 Replikasi 1 0.021871 3.38 132.3 26.64 0.5 22000 1 0.4 1 0.08341 150.73

12b NaNO2 (350) 1200 0.004 0.025498 Replikasi 2








48

4.3 Analisa dan Pembahasan

4.3.1 Analisa Hasil Pengujian Laju Korosi Konsentrasi NaCl 1000 ppm

Analisa hasil pengujian laju korosi dengan menggunakan larutan NaCl

1000 ppm ditunjukkan oleh gambar dibawah ini:

Gambar 4.11 Grafik Laju Korosi Konsentrasi NaCl 1000 ppm (data pribadi)

Dari grafik diatas menunjukkan bahwa laju korosi dengan

menggunakan konsentrasi NaCl sebesar 1000 ppm yang terjadi pada

konsentrasi 0 ppm (tanpa inhibitor) sebesar 0.040166 mm/year. Untuk laju

korosi pada inhibitor NaNO2 dengan konsentrasi 150 ppm terjadi korosi

sebesar 0.031896 mm/year, konsentrasi 250 ppm terjadi korosi sebesar

0.026517 mm/year dan konsentrasi 350 ppm terjadi korosi sebesar 0.025594

mm/year. Sedangkan untuk laju korosi pada inhibitor Na2CrO4 dengan

konsentrasi 150 ppm terjadi korosi sebesar 0.03333 mm/year, konsentrasi 250

ppm terjadi korosi sebesar 0.02757 mm/year dan konsentrasi 350 ppm terjadi

korosi sebesar 0.02667 mm/year. Dari grafik diatas menunjukkan penurunan

laju korosi pada inhibitor NaNO2 dan Na2CrO4 dikarenakan semakin tinggi

konsentrasi inhibitor maka semakin kecil laju korosi yang terjadi dan

inhibitor NaNO2 memiliki laju korosi yang lebih rendah dibandingkan

dengan Na2CrO4 pada konsentrasi NaCl 1000 ppm.

0.0250

0.0270

0.0290

0.0310

0.0330

0.0350

0.0370

0.0390

0.0410

0 150 250 350

Laju

Ko

rosi

(m

m/y

ear)


Laju Korosi Konsentrasi NaCl 1000 ppm

Na2CrO4

NaNO2

49

4.3.2 Analisa Hasil Pengujian Laju Korosi Konsentrasi NaCl 1100 ppm











konsentrasi 150 ppm terjadi korosi sebesar 0.035184 mm/year, konsentrasi

250 ppm terjadi korosi sebesar 0.028845 mm/year dan konsentrasi 350 ppm

terjadi korosi sebesar 0.026508 mm/year. Dari grafik diatas menunjukkan

penurunan laju korosi pada inhibitor NaNO2 dan Na2CrO4 dikarenakan

semakin tinggi konsentrasi inhibitor maka semakin kecil laju korosi yang

terjadi dan inhibitor NaNO2 memiliki laju korosi yang lebih rendah

dibandingkan dengan Na2CrO4 pada konsentrasi NaCl 1100 ppm.

0.0240

0.0265

0.0289

0.0314

0.0338

0.0363

0.0387

0.0412

0.0436

0.0461

0 150 250 350

Laju

Ko

rosi

(m

m/y

ear)



Na2CrO4

NaNO2

50

4.3.3 Analisa Laju Korosi Konsentrasi NaCl 1200 ppm











konsentrasi 150 ppm terjadi korosi sebesar 0.036618 mm/year, konsentrasi

250 ppm terjadi korosi sebesar 0.030110 mm/year dan konsentrasi 350 ppm

terjadi korosi sebesar 0.023999 mm/year. Dari grafik diatas menunjukkan

penurunan laju korosi pada inhibitor NaNO2 dan Na2CrO4 dikarenakan

semakin tinggi konsentrasi inhibitor maka semakin kecil laju korosi yang

terjadi dan inhibitor NaNO2 memiliki laju korosi yang lebih rendah

dibandingkan dengan Na2CrO4 pada konsentrasi NaCl 1200 ppm.

0.0200

0.0234

0.0268

0.0302

0.0336

0.0370

0.0404

0.0438

0.0472

0 150 250 350

Laju

Ko

rosi

(m

m/y

ear

)



Na2CrO4

NaNO2

51

4.3.4 Analisa Hasil Perhitungan Efisiensi Inhibitor Konsentrasi NaCl 1000 ppm

Analisa hasil perhitungan efisiensi inhibitor pada konsentrasi NaCl

1000 ppm, dapat ditunjukkan oleh gambar dibawah ini:

Gambar 4.14 Grafik Efisiensi Inhibitor Konsentrasi NaCl 1000 ppm (data pribadi)

Dari grafik diatas menunjukkan bahwa efisiensi inhibitor pada

konsentrasi NaCl 1000 ppm yang terjadi pada konsentrasi 0 ppm (tanpa

inhibitor) sebesar 0%. Untuk inhibitor NaNO2 dengan konsentrasi 150 ppm

memiliki efisiensi sebesar 0,206%, konsentrasi 250 ppm memiliki efisiensi

sebesar 0,340% dan konsentrasi 350 ppm memiliki efisiensi sebesar 0,363%.

Sedangkan untuk inhibitor Na2CrO4 dengan konsentrasi 150 ppm memiliki

efisiensi sebesar 0,170%, konsentrasi 250 ppm memiliki efisiensi sebesar

0,314% dan konsentrasi 350 ppm memiliki efisiensi sebesar 0,336%. Dari

grafik diatas menunjukkan inhibitor NaNO2 memiliki nilai efisiensi lebih

tinggi dibandingkan dengan inhibitor Na2CrO4 pada konsentrasi NaCl 1000

ppm.

0.000

0.040

0.080

0.120

0.160

0.200

0.240

0.280

0.320

0.360

0.400

0 150 250 350

Efis

ien

si In

hib

ito

r (%

)


Efisiensi Inhibitor NaCl 1000 ppm

NaNO2

Na2CrO4

52








memiliki efisiensi sebesar 0,276%, konsentrasi 250 ppm memiliki eiesiensi







ppm.




0.000

0.050

0.100

0.150

0.200

0.250

0.300

0.350

0.400

0.450

0.500

0 150 250 350

Efis

ien

si In

hib

ito

r (%

)



NaNO2

Na2CrO4

53





memiliki efisiensi sebesar 0,272%, konsentrasi 250 ppm memiliki eiesiensi







ppm.

4.3.7 Analisa Hasil Perhitungan Remaining Life Konsentrasi NaCl 1000 ppm

Analisa hasil perhitungan lifetime pada konsentrasi NaCl 1000 ppm,

dapat ditunjukkan oleh gambar dibawah ini:

0.0000

0.0600

0.1200

0.1800

0.2400

0.3000

0.3600

0.4200

0.4800

0.5400

0.6000

0 150 250 350

Efis

ien

si In

hib

ito

r (%

)



NaNO2

Na2CrO4

54

Gambar 4.17 Grafik Remaining Life Konsentrasi NaCl 1000 ppm (data pribadi)

Dari grafik diatas menunjukkan bahwa Remaining Life pada


inhibitor) sebesar 82.07 tahun. Untuk inhibitor NaNO2 dengan konsentrasi

150 ppm memiliki lifetime sebesar 103.36 tahun, konsentrasi 250 ppm

memiliki lifetime 124.32 tahun dan konsentrasi 350 ppm memiliki lifetime

sebesar 128.80 tahun. Sedangkan untuk inhibitor Na2CrO4 dengan

konsentrasi 150 ppm memiliki lifetime sebesar 98.91 tahun, konsentrasi 250

ppm memiliki lifetime sebesar 119.56 tahun dan konsentrasi 350 ppm

memiliki efisiensi sebesar 123.63 tahun. Dari grafik diatas menunjukkan

inhibitor NaNO2 memiliki nilai lifetime yang lebih tinggi dibandingkan

dengan inhibitor Na2CrO4 pada konsentrasi NaCl 1000 ppm.




80

85

90

95

100

105

110

115

120

125

130

0 150 250 350

Rem

ain

ing

Life

(ye

ar)


Remaining Life Konsentrasi NaCl 1000 ppm

NaNO2

Na2CrO4

55






memiliki lifetime sebesar 130.57 tahun dan konsentrasi 350 ppm memiliki

lifetime sebesar 136.51 tahun. Sedangkan untuk inhibitor Na2CrO4 dengan









70

77

84

91

98

105

112

119

126

133

140

0 150 250 350

Rem

ain

ing

Life

(ye

ar)



NaNO2

Na2CrO4

56






memiliki lifetime sebesar 119.22 tahun dan konsentrasi 350 ppm memiliki

lifetime sebesar 150.73 tahun. Sedangkan untuk inhibitor Na2CrO4 dengan






60

70

80

90

100

110

120

130

140

150

160

0 150 250 350

Rem

ain

ing

Life

(yea

r)



NaNO2

Na2CrO4

BAB 5

KESIMPULAN DAN SARAN

57

BAB 5

KESIMPULAN DAN SARAN

5.1 Kesimpulan

Dari hasil pengolahan data dan analisis pada bab sebelumnya, maka dapat

diambil kesimpulan sebagai berikut :

1. Dari pengujian laju korosi dengan menggunakan metode weight loss

dengan hasil rata-rata dari masing masing variabel inhibitor menunjukkan

hasil laju korosi terendah menggunakan inhibitor NaNO2, dengan

konsentrasi NaCl 1200 ppm, yaitu sebesar 0.021817 mm/y sedangkan pada

inhibitor Na2CrO4 memiliki laju korosi terendah sebesar 0.023999 mm/y.

Hal tersebut menunjukkan penggunaan inhibitor NaNO2 memiliki hasil

laju korosi jauh lebih kecil dibandingkan dengan menggunakan inhibitor

Na2CrO4.

2. Berdasarkan perhitungan remaining life yang didapat dari perhitungan laju

korosi dengan membandingkan 2 inhibitor yakni NaNO2 dan Na2CrO4

didapatkan remaining life tertinggi adalah inhbitor NaNO2 sebesar 150.73

tahun sedangkan pada inhibitor Na2CrO4 sebesar 137.37 tahun. Hal

tersebut menunjukkan perlindungan korosi untuk pipa ASTM A105 dipilih

dengan menggunakan inhibitor NaNO2 karena memiliki remaining life

yang lebih lama dibandingkan dengan inhibitor Na2CrO4.

3. Penggunaan inhibitor yang paling efektif untuk material ASTM A105

adalah menggunakan inhibitor NaNO2 dengan nilai efisiensi sebesar

0.537%. Semakin besar konsentrasi inhibitor, maka semakin kecil laju

korosinya. Demikian pula dengan semakin lama usia pakai, maka semakin

tinggi nilai efisiensi suatu material.

5.2 Saran

Dari penelitian tugas akhir ini terdapat beberapa saran untuk kelanjutan

pengembangan dan penelitian selanjutnya, antara lain:

58

1. Penelitian selanjutnya dapat menggunakan inhibitor yang berbeda dan

menambahkan variabel lain sebagai parameter pengujian.

2. Penelitian selanjutnya dapat menambah metode pengujian lainnya untuk

mendapatkan kualitas penggunaan inhibitor yang lebih baik

3. Penelitian selanjutnya dapat menambahkan perhitungan ekonomis.

DAFTAR PUSTAKA

59

DAFTAR PUSTAKA

ASME B31.3. (2014). Process Piping. Chemical Engineer (Vol. ASME Code)

API 570, Piping Inspection Code : In-service Inspection , Rating , Repair , and

Alteration of Piping Systems. (2010), Edition, T(November 2009).

https://doi.org/10.1109/TSMCC.2011.2109710

ASTM-G01–03. (2011). Standard Practice for Preparing, Cleaning, and Evaluating

Corrosion Test Specimens. Annual Book of ASTM Standards, 1–9.

https://doi.org/10.1520/G0001-03R11

ASTM-G31–72. (2004). Standard Practice for Laboratory Immersion Corrosion

Testing of Metals. American Society for Testing and Materials, 72

(Reapproved), 1–8. https://doi.org/10.1520/G0031-72R04

ASTM A105. (2010). Standard Specification for Carbon Steel Forgings for Piping

Applications.

Atmadja, S. T. (2010). Pengendalian korosi pada sistem pendingin menggunakan

penambahan zat inhibitor. Rotasi, 12(2), 7–13.

https://doi.org/10.2307/1238223

Damayanti, E. A. (2018). Analisis Laju Korosi dan Lifetime Pipa Underground

Baja Karbon A53 dengan Wrapping Protection. Proceeding 3rd Conference

of Piping Engineering and Its Applicationrd, (Corrosion), 193–198.

Firdausi, Agung. 2012. “Penyebab Korosi dan Laju Korosi” (Tanggal 2 Januari

2018 http://www.agungfirdausi.my.id/2012/04/faktor-faktor-yang-

mempengaruhi-korosi.html)

Fontana, M. G. (1986). Corrosion engineering Series in materials science and

engineering.

https://doi.org/10.1109/TSMCC.2011.2109710

http://www.agungfirdausi.my.id/2012/04/faktor-faktor-yang-mempengaruhi-korosi.html

http://www.agungfirdausi.my.id/2012/04/faktor-faktor-yang-mempengaruhi-korosi.html

Furqan, Muhammad. 2013. “Corrosion Engineer: Macam-macam Bentuk Korosi”

(Tanggal 2 Januari http://m10mechanicalengineering.blogspot.co.id/

2013/11/macam-macambentuk-korosi.html)

Ganesya, A. B. (2018). Pengaruh Variasi Kelembaban , Temperatur Dan Ketebalan

Cat Pada Material a53 Grade B Terhadap Laju Korosi Di Pt Pjb Ubjom

Pacitan, 151–156.

Khuncoro, D. B. (2018). Perbandingan Inhibitor NaNO3 Dengan K2CrO4 Pada

Material Stainless Steel 316L Terhadap Laju Korosi Fluida Sulfuric Acid,

229–234.

Pratiwi, W. D., & Setiawan, A. (2015). Korosi: Ratapan Dibalik Sanjungan:

Politeknik Perkapalan Negeri Surabaya

Roberge, P. R. (1999). Handbook of Corrosion Engineering.

https://doi.org/10.1016/S0026-0576(00)83445-5

Suherman, Wahid. (1987). Pengetahuan Bahan. Surabaya: Institut Teknologi

Sepuluh Nopember Surabaya

Utomo, S. (2015). PENGARUH KONSENTRASI LARUTAN NaNO 2 SEBAGAI

INHIBITOR, 7(2). https://doi.org/10.1080/0194436070165323


LAMPIRAN A

ASTM G1

Designation : G 1 – 03

Standard Practice forPreparing, Cleaning, and Evaluating Corrosion TestSpecimens 1

This standard is issued under the fixed designation G 1; the number immediately following the designation indicates the year of originaladoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. A superscriptepsilon (e) indicates an editorial change since the last revision or reapproval.

1. Scope

1.1 This practice covers suggested procedures for preparingbare, solid metal specimens for tests, for removing corrosionproducts after the test has been completed, and for evaluatingthe corrosion damage that has occurred. Emphasis is placed onprocedures related to the evaluation of corrosion by mass lossand pitting measurements. (Warning— In many cases thecorrosion product on the reactive metals titanium and zirco-nium is a hard and tightly bonded oxide that defies removal bychemical or ordinary mechanical means. In many such cases,corrosion rates are established by mass gain rather than massloss.)

1.2 This standard does not purport to address all of thesafety concerns, if any, associated with its use. It is theresponsibility of the user of this standard to establish appro-priate safety and health practices and determine the applica-bility of regulatory limitations prior to use.For specificprecautionary statements, see 1 and 7.2.

2. Referenced Documents

2.1 ASTM Standards:A 262 Practices for Detecting Susceptibility to Intergranu-

lar Attack in Austenitic Stainless Steels2

D 1193 Specification for Reagent Water3

D 1384 Test Method for Corrosion Test for Engine Coolantsin Glassware4

D 2776 Test Methods for Corrosivity of Water in the Ab-sence of Heat Transfer (Electrical Methods)5

G 15 Terminology Relating to Corrosion and CorrosionTesting6

G 16 Guide for Applying Statistics to Analysis of CorrosionData6

G 31 Practice for Laboratory Immersion Corrosion Testingof Metals6

G 33 Practice for Recording Data from Atmospheric Cor-rosion Tests of Metallic-Coated Steel Specimens6

G 46 Guide for Examination and Evaluation of PittingCorrosion6

G 50 Practice for Conducting Atmospheric Corrosion Testson Metals6

G 78 Guide for Crevice Corrosion Testing of Iron Base andNickel-Base Stainless Alloys in Seawater and OtherChloride-Containing Aqueous Environments6

3. Terminology

3.1 See Terminology G 15 for terms used in this practice.

4. Significance and Use

4.1 The procedures given are designed to remove corrosionproducts without significant removal of base metal. This allowsan accurate determination of the mass loss of the metal or alloythat occurred during exposure to the corrosive environment.

4.2 These procedures, in some cases, may apply to metalcoatings. However, possible effects from the substrate must beconsidered.

5. Reagents and Materials

5.1 Purity of Reagents—Reagent grade chemicals shall beused in all tests. Unless otherwise indicated, it is intended thatall reagents conform to the specifications of the Committee onAnalytical Reagents of the American Chemical Society wheresuch specifications are available.7 Other grades may be used,provided it is first ascertained that the reagent is of sufficientlyhigh purity to permit its use without lessening the accuracy ofthe determination.

5.2 Purity of Water—Unless otherwise indicated, referencesto water shall be understood to mean reagent water as definedby Type IV of Specification D 1193.

1 This practice is under the jurisdiction of ASTM Committee G01 on Corrosionof Metals and is the direct responsibility of Subcommittee G01.05 on LaboratoryCorrosion Tests.

Current edition approved October 1, 2003. Published October 2003. Originallyapproved in 1967. Last previous edition approved in 1999 asG 1 – 90(1999)e1.

2 Annual Book of ASTM Standards, Vol 01.03.3 Annual Book of ASTM Standards, Vol 11.01.4 Annual Book of ASTM Standards, Vol 15.05.5 Discontinued, replaced by Guide G 96. See 1990Annual Book of ASTM

Standards,Vol 03.02.6 Annual Book of ASTM Standards, Vol 03.02.

7 Reagent Chemicals, American Chemical Society Specifications, AmericanChemical Society, Washington, DC. For suggestions on the testing of reagents notlisted by the American Chemical Society, seeAnalar Standards for LaboratoryChemicals, BDH Ltd., Poole, Dorset, U.K., and theUnited States Pharmacopeiaand National Formulary, U.S. Pharmacopeial Convention, Inc. (USPC), Rockville,MD.

1

Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.

6. Methods for Preparing Specimens for Test

6.1 For laboratory corrosion tests that simulate exposure toservice environments, a commercial surface, closely resem-bling the one that would be used in service, will yield the mostmeaningful results.

6.2 It is desirable to mark specimens used in corrosion testswith a unique designation during preparation. Several tech-niques may be used depending on the type of specimen andtest.

6.2.1 Stencil or Stamp—Most metallic specimens may bemarked by stenciling, that is, imprinting the designation codeinto the metal surface using hardened steel stencil stamps hitwith a hammer. The resulting imprint will be visible even aftersubstantial corrosion has occurred. However, this procedureintroduces localized strained regions and the possibility ofsuperficial iron contamination in the marked area.

6.2.2 Electric engraving by means of a vibratory markingtool may be used when the extent of corrosion damage isknown to be small. However, this approach to marking is muchmore susceptible to having the marks lost as a result ofcorrosion damage during testing.

6.2.3 Edge notching is especially applicable when extensivecorrosion and accumulation of corrosion products is antici-pated. Long term atmospheric tests and sea water immersiontests on steel alloys are examples where this approach isapplicable. It is necessary to develop a code system when usingedge notches.

6.2.4 Drilled holes may also be used to identify specimenswhen extensive metal loss, accumulation of corrosion products,or heavy scaling is anticipated. Drilled holes may be simplerand less costly than edge notching. A code system must bedeveloped when using drilled holes. Punched holes should notbe used as they introduce residual strain.

6.2.5 When it is undesirable to deform the surface ofspecimens after preparation procedures, for example, whentesting coated surfaces, tags may be used for specimen identi-fication. A metal or plastic wire can be used to attach the tag tothe specimen and the specimen identification can be stampedon the tag. It is important to ensure that neither the tag nor thewire will corrode or degrade in the test environment. It is alsoimportant to be sure that there are no galvanic interactionsbetween the tag, wire, and specimen.

6.3 For more searching tests of either the metal or theenvironment, standard surface finishes may be preferred. Asuitable procedure might be:

6.3.1 Degrease in an organic solvent or hot alkaline cleaner.(See also Practice G 31.)

NOTE 1—Hot alkalies and chlorinated solvents may attack some metals.

NOTE 2—Ultrasonic cleaning may be beneficial in both pre-test andpost-test cleaning procedures.

6.3.2 Pickle in an appropriate solution if oxides or tarnishare present. In some cases the chemical cleaners described inSection 6 will suffice.

NOTE 3—Pickling may cause localized corrosion on some materials.

6.3.3 Abrade with a slurry of an appropriate abrasive or withan abrasive paper (see Practices A 262 and Test Method

D 1384). The edges as well as the faces of the specimensshould be abraded to remove burrs.

6.3.4 Rinse thoroughly, hot air dry, and store in desiccator.6.4 When specimen preparation changes the metallurgical

condition of the metal, other methods should be chosen or themetallurgical condition must be corrected by subsequent treat-ment. For example, shearing a specimen to size will cold workand may possibly fracture the edges. Edges should be ma-chined.

6.5 The clean, dry specimens should be measured andweighed. Dimensions determined to the third significant figureand mass determined to the fifth significant figure are sug-gested. When more significant figures are available on themeasuring instruments, they should be recorded.

7. Methods for Cleaning After Testing

7.1 Corrosion product removal procedures can be dividedinto three general categories: mechanical, chemical, and elec-trolytic.

7.1.1 An ideal procedure should remove only corrosionproducts and not result in removal of any base metal. Todetermine the mass loss of the base metal when removingcorrosion products, replicate uncorroded control specimensshould be cleaned by the same procedure being used on the testspecimen. By weighing the control specimen before and aftercleaning, the extent of metal loss resulting from cleaning canbe utilized to correct the corrosion mass loss.

NOTE 4—It is desirable to scrape samples of corrosion products beforeusing any chemical techniques to remove them. These scrapings can thenbe subjected to various forms of analyses, including perhaps X-raydiffraction to determine crystal forms as well as chemical analyses to lookfor specific corrodants, such as chlorides. All of the chemical techniquesthat are discussed in Section 7 tend to destroy the corrosion products andthereby lose the information contained in these corrosion products. Caremay be required so that uncorroded metal is not removed with thecorrosion products.

7.1.2 The procedure given in 7.1.1 may not be reliable whenheavily corroded specimens are to be cleaned. The applicationof replicate cleaning procedures to specimens with corrodedsurfaces will often, even in the absence of corrosion products,result in continuing mass losses. This is because a corrodedsurface, particularly of a multiphase alloy, is often moresusceptible than a freshly machined or polished surface tocorrosion by the cleaning procedure. In such cases, thefollowing method of determining the mass loss due to thecleaning procedure is preferred.

7.1.2.1 The cleaning procedure should be repeated on speci-mens several times. The mass loss should be determined aftereach cleaning by weighing the specimen.

7.1.2.2 The mass loss should be graphed as a function of thenumber of equal cleaning cycles as shown in Fig. 1. Two lineswill be obtained: AB and BC. The latter will correspond tocorrosion of the metal after removal of corrosion products. Themass loss due to corrosion will correspond approximately topoint B.

7.1.2.3 To minimize uncertainty associated with corrosionof the metal by the cleaning method, a method should bechosen to provide the lowest slope (near to horizontal) of lineBC.

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7.1.3 Repeated treatment may be required for completeremoval of corrosion products. Removal can often be con-firmed by examination with a low power microscope (forexample, 73 to 303). This is particularly useful with pittedsurfaces when corrosion products may accumulate in pits. Thisrepeated treatment may also be necessary because of therequirements of 7.1.2.1. Following the final treatment, thespecimens should be thoroughly rinsed and immediately dried.

7.1.4 All cleaning solutions shall be prepared with waterand reagent grade chemicals.

7.2 Chemical procedures involve immersion of the corro-sion test specimen in a specific solution that is designed toremove the corrosion products with minimal dissolution of anybase metal. Several procedures are listed in Table A1.1. Thechoice of chemical procedure to be used is partly a matter oftrial and error to establish the most effective method for aspecific metal and type of corrosion product scale.(Warning—These methods may be hazardous to personnel).

7.2.1 Chemical cleaning is often preceded by light brushing(non metallic bristle) or ultrasonic cleaning of the test speci-men to remove loose, bulky corrosion products.

7.2.2 Intermittent removal of specimens from the cleaningsolution for light brushing or ultrasonic cleaning can oftenfacilitate the removal of tightly adherent corrosion products.

7.2.3 Chemical cleaning is often followed by light brushingor ultrasonic cleaning in reagent water to remove looseproducts.

7.3 Electrolytic cleaning can also be utilized for removal ofcorrosion products. Several useful methods for corrosion testspecimens of iron, cast iron, or steel are given in Table A2.1.

7.3.1 Electrolytic cleaning should be preceded by brushingor ultrasonic cleaning of the test specimen to remove loose,bulky corrosion products. Brushing or ultrasonic cleaningshould also follow the electrolytic cleaning to remove anyloose slime or deposits. This will help to minimize anyredeposition of metal from reducible corrosion products thatwould reduce the apparent mass loss.

7.4 Mechanical procedures can include scraping, scrubbing,brushing, ultrasonic cleaning, mechanical shocking, and im-pact blasting (for example, grit blasting, water-jet blasting, andso forth). These methods are often utilized to remove heavilyencrusted corrosion products. Scrubbing with a nonmetallicbristle brush and a mild abrasive-distilled water slurry can alsobe used to remove corrosion products.

7.4.1 Vigorous mechanical cleaning may result in the re-moval of some base metal; therefore, care should be exercised.These should be used only when other methods fail to provideadequate removal of corrosion products. As with other meth-ods, correction for metal loss due to the cleaning method isrecommended. The mechanical forces used in cleaning shouldbe held as nearly constant as possible.

8. Assessment of Corrosion Damage

8.1 The initial total surface area of the specimen (makingcorrections for the areas associated with mounting holes) andthe mass lost during the test are determined. The averagecorrosion rate may then be obtained as follows:

Corrosion Rate5 ~K 3 W!/~A 3 T 3 D! (1)

where:K = a constant (see 8.1.2),T = time of exposure in hours,A = area in cm2,W = mass loss in grams, andD = density in g/cm3 (see Appendix X1).

8.1.1 Corrosion rates are not necessarily constant with timeof exposure. See Practice G 31 for further guidance.

8.1.2 Many different units are used to express corrosionrates. Using the units in 7.1 forT, A, W, andD, the corrosionrate can be calculated in a variety of units with the followingappropriate value ofK:

Corrosion Rate Units DesiredConstant (K) in Corrosion

Rate Equationmils per year (mpy) 3.45 3 106

inches per year (ipy) 3.45 3 103

inches per month (ipm) 2.87 3 102

millimetres per year (mm/y) 8.76 3 104

micrometres per year (um/y) 8.76 3 107

picometres per second (pm/s) 2.78 3 106

grams per square meter per hour (g/m2·h) 1.00 3 104 3 Dmilligrams per square decimeter per day (mdd) 2.40 3 106 3 Dmicrograms per square meter per second (µg/m2·s) 2.78 3 106 3 D

NOTE 5—If desired, these constants may also be used to convertcorrosion rates from one set of units to another. To convert a corrosion ratein units X to a rate in unitsY, multiply by KY/KX; for example:

15 mpy5 153 ~2.783 106!/~3.453 106! pm/s (2)

8.1.3 In the case of sacrificial alloy coatings for which thereis preferential corrosion of a component whose density differsfrom that of the alloy, it is preferable to use the density of thecorroded component (instead of the initial alloy density) forcalculating average thickness loss rate by use of Eq 1. This isdone as follows: (1) cleaning to remove corrosion productsonly and determine the mass loss of the corroded component;(2) stripping the remaining coating to determine the mass of theuncorroded component; (3) chemical analysis of the strippingsolution to determine the composition of the uncorroded

FIG. 1 Mass Loss of Corroded Specimens Resulting fromRepetitive Cleaning Cycles

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component; (4) performing a mass balance to calculate thecomposition of the corroded component; (5) using the massand density of the corroded component to calculate the averagethickness loss rate by use of Eq 1. An example of thisprocedure is given in Appendix X2.

The procedure described above gives an average penetrationrate of the coating, but the maximum penetration for amultiphase alloy may be larger when the corroded phase is notuniformly distributed across the surface. In such cases, it isgenerally considered good practice to obtain a cross sectionthrough the corroded surface for microscopic examination.This examination will reveal the extent of selective corrosionof particular phases in the coating, and help in understandingthe mechanism of attack.

8.2 Corrosion rates calculated from mass losses can bemisleading when deterioration is highly localized, as in pittingor crevice corrosion. If corrosion is in the form of pitting, itmay be measured with a depth gage or micrometer caliperswith pointed anvils (see Guide G 46). Microscopical methodswill determine pit depth by focusing from top to bottom of thepit when it is viewed from above (using a calibrated focusingknob) or by examining a section that has been mounted andmetallographically polished. The pitting factor is the ratio ofthe deepest metal penetration to the average metal penetration(as measured by mass loss).

NOTE 6—See Guide G 46 for guidance in evaluating depths of pitting.NOTE 7—See Guide G 78 for guidance in evaluating crevice corrosion.

8.3 Other methods of assessing corrosion damage are:8.3.1 Appearance—The degradation of appearance by rust-

ing, tarnishing, or oxidation. (See Practice G 33.)8.3.2 Mechanical Properties—An apparent loss in tensile

strength will result if the cross-sectional area of the specimen(measured before exposure to the corrosive environment) isreduced by corrosion. (See Practice G 50.) Loss in tensilestrength will result if a compositional change, such as dealloy-ing taking place. Loss in tensile strength and elongation willresult from localized attack, such as cracking or intergranularcorrosion.

8.3.3 Electrical Properties—Loss in electrical conductivitycan be measured when metal loss results from uniformcorrosion. (See Test Methods D 2776.)

8.3.4 Microscopical Examination—Dealloying, exfoliation,cracking, or intergranular attack may be detected by metallo-graphic examination of suitably prepared sections.

9. Report

9.1 The report should include the compositions and sizes ofspecimens, their metallurgical conditions, surface preparations,and cleaning methods as well as measures of corrosiondamage, such as corrosion rates (calculated from mass losses),maximum depths of pitting, or losses in mechanical properties.

10. Precision and Bias

10.1 The factors that can produce errors in mass lossmeasurement include improper balance calibration and stan-dardization. Generally, modern analytical balances can deter-mine mass values to60.2 mg with ease and balances areavailable that can obtain mass values to60.02 mg. In general,mass measurements are not the limiting factor. However,inadequate corrosion product removal or overcleaning willaffect precision.

10.2 The determination of specimen area is usually the leastprecise step in corrosion rate determinations. The precision ofcalipers and other length measuring devices can vary widely.However, it generally is not necessary to achieve better than61 % for area measurements for corrosion rate purposes.

10.3 The exposure time can usually be controlled to betterthan 61 % in most laboratory procedures. However, in fieldexposures, corrosive conditions can vary significantly and theestimation of how long corrosive conditions existed canpresent significant opportunities for error. Furthermore, corro-sion processes are not necessarily linear with time, so that ratevalues may not be predictive of the future deterioration, butonly are indications of the past exposure.

10.4 Regression analysis on results, as are shown in Fig. 1,can be used to obtain specific information on precision. SeeGuide G 16 for more information on statistical analysis.

10.5 Bias can result from inadequate corrosion productremoval or metal removal caused by overcleaning. The use ofrepetitive cleaning steps, as shown in Fig. 1, can minimize bothof these errors.

10.5.1 Corrosion penetration estimations based on mass losscan seriously underestimate the corrosion penetration causedby localized processes, such as pitting, cracking, crevicecorrosion, and so forth.

11. Keywords

11.1 cleaning; corrosion product removal; evaluation; massloss; metals; preparation; specimens

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ANNEXES

(Mandatory Information)

A1. CHEMICAL CLEANING PROCEDURES

TABLE A1.1 CHEMICAL CLEANING PROCEDURES FOR REMOVAL OF CORROSION PRODUCTS

Designation Material Solution Time Temperature Remarks

C.1.1 Aluminum and Alu-minum Alloys

50 mL phosphoric acid (H3PO4, sp gr 1.69)20 g chromium trioxide (CrO3)Reagent water to make 1000 mL

5 to 10 min 90°C to Boiling If corrosion product films remain, rinse, thenfollow with nitric acid procedure (C.1.2).

C.1.2 Nitric acid (HNO3, sp gr 1.42) 1 to 5 min 20 to 25°C Remove extraneous deposits and bulkycorrosion products to avoid reactions thatmay result in excessive removal of basemetal.

C.2.1 Copper and CopperAlloys

500 mL hydrochloric acid (HCl, sp gr 1.19)Reagent water to make 1000 mL

1 to 3 min 20 to 25°C Deaeration of solution with purified nitrogenwill minimize base metal removal.

C.2.2 4.9 g sodium cyanide (NaCN)Reagent water to make 1000 mL

1 to 3 min 20 to 25°C Removes copper sulfide corrosion productsthat may not be removed by hydrochloricacid treatment (C.2.1).

C.2.3 100 mL sulfuric acid (H2SO4, sp gr 1.84)Reagent water to make 1000 mL

1 to 3 min 20 to 25°C Remove bulky corrosion products beforetreatment to minimize copper redepositionon specimen surface.

C.2.4 120 mL sulfuric acid (H2SO4, sp gr 1.84)30 g sodium dichromate (Na2Cr2O7·2H2O)Reagent water to make 1000 mL

5 to 10 s 20 to 25°C Removes redeposited copper resulting fromsulfuric acid treatment.


30 to 60 min 40 to 50°C Deaerate solution with nitrogen. Brushing oftest specimens to remove corrosionproducts followed by re-immersion for 3 to4 s is recommended.

C.3.1 Iron and Steel 1000 mL hydrochloric acid (HCl, sp gr 1.19)20 g antimony trioxide (Sb2O3)50 g stannous chloride (SnCl2)

1 to 25 min 20 to 25°C Solution should be vigorously stirred orspecimen should be brushed. Longer timesmay be required in certain instances.

C.3.2 50 g sodium hydroxide (NaOH)200 g granulated zinc or zinc chipsReagent water to make 1000 mL

30 to 40 min 80 to 90°C Caution should be exercised in the use ofany zinc dust since spontaneous ignitionupon exposure to air can occur.

C.3.3 200 g sodium hydroxide (NaOH)20 g granulated zinc or zinc chipsReagent water to make 1000 mL

30 to 40 min 80 to 90°C Caution should be exercised in the use ofany zinc dust since spontaneous ignitionupon exposure to air can occur.

C.3.4 200 g diammonium citrate((NH4)2HC6H5O7)

Reagent water to make 1000 mL

20 min 75 to 90°C Depending upon the composition of thecorrosion product, attack of base metalmay occur.

C.3.5 500 mL hydrochloric acid (HCl, sp gr 1.19)3.5 g hexamethylene tetramineReagent water to make 1000 mL

10 min 20 to 25°C Longer times may be required in certaininstances.

C.3.6 Molten caustic soda (NaOH) with1.5–2.0 % sodium hydride (NaH)

1 to 20 min 370°C For details refer to Technical InformationBulletin SP29-370, “DuPont SodiumHydride Descaling Process OperatingInstructions.’’

C.4.1 Lead and Lead Alloys 10 mL acetic acid (CH3COOH)Reagent water to make 1000 mL

5 min Boiling ...

C.4.2 50 g ammonium acetate (CH3COONH4)Reagent water to make 1000 mL

10 min 60 to 70°C ...


5 min 60 to 70°C ...

C.5.1 Magnesium and Mag-nesium Alloys

150 g chromium trioxide (CrO3)10 g silver chromate (Ag2CrO4)Reagent water to make 1000 mL

1 min Boiling The silver salt is present to precipitatechloride.

C.5.2 200 g chromium trioxide (CrO3)10 g silver nitrate (AgNO3)20 g barium nitrate (Ba(NO3)2)Reagent water to make 1000 mL

1 min 20 to 25°C The barium salt is present to precipitatesulfate.

C.6.1 Nickel and NickelAlloys

150 mL hydrochloric acid (HCl, sp gr 1.19)Reagent water to make 1000 mL

1 to 3 min 20 to 25°C ...


1 to 3 min 20 to 25°C ...

C.7.1 Stainless Steels 100 mL nitric acid (HNO3, sp gr 1.42)Reagent water to make 1000 mL

20 min 60°C ...

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TABLE A1.1 Continued


C.7.2 150 g diammonium citrate((NH4)2HC6H5O7)


10 to 60 min 70°C ...

C.7.3 100 g citric acid (C6H8O7)50 mL sulfuric acid (H2SO4, sp gr 1.84)2 g inhibitor (diorthotolyl thiourea or

quinoline ethyliodide or betanaphtholquinoline)


5 min 60°C ...

C.7.4 200 g sodium hydroxide (NaOH)30 g potassium permanganate (KMnO4)Reagent water to make 1000 mL

followed by100 g diammonium citrate

((NH4)2HC6H5O7)Reagent water to make 1000 mL

5 min Boiling ...

C.7.5 100 mL nitric acid (HNO3, sp gr 1.42)20 mL hydrofluoric acid (HF, sp gr

1.198–48 %)Reagent water to make 1000 mL

5 to 20 min 20 to 25°C ...

C.7.6 200 g sodium hydroxide (NaOH)50 g zinc powderReagent water to make 1000 mL

20 min Boiling Caution should be exercised in the use ofany zinc dust since spontaneous ignitionupon exposure to air can occur.

C.8.1 Tin and Tin Alloys 150 g trisodium phosphate(Na3PO4·12H2O)


10 min Boiling ...

C.8.2 50 mL hydrochloric acid (HCl, sp gr 1.19)Reagent water to make 1000 mL

10 min 20°C ...

C.9.1 Zinc and Zinc Alloys 150 mL ammonium hydroxide (NH4OH,sp gr 0.90)

Reagent water to make 1000 mLfollowed by

5 min 20 to 25°C ...

50 g chromium trioxide (CrO3)10 g silver nitrate (AgNO3)Reagent water to make 1000 mL

15 to 20 s Boiling The silver nitrate should be dissolved in waterand added to the boiling chromic acid toprevent excessive crystallization of silverchromate. The chromic acid must besulfate free to avoid attack of the zinc basemetal.

C.9.2 100 g ammonium chloride (NH4Cl)Reagent water to make 1000 mL

2 to 5 min 70°C ...

C.9.3 200 g chromium trioxide (CrO3)Reagent water to make 1000 mL

1 min 80°C Chloride contamination of the chromic acidfrom corrosion products formed in saltenvironments should be avoided to preventattack of the zinc base metal.

C.9.4 85 mL hydriodic acid (HI, sp gr 1.5)Reagent water to make 1000 mL

15 s 20 to 25°C Some zinc base metal may be removed. Acontrol specimen (3.1.1) should beemployed.

C.9.5 100 g ammonium persulfate ((NH4)2S2O8)Reagent water to make 1000 mL

5 min 20 to 25°C Particularly recommended for galvanizedsteel.


2 to 5 min 70°C ...

A2. ELECTROLYTIC CLEANING PROCEDURES

TABLE A2.1 ELECTROLYTIC CLEANING PROCEDURES FOR REMOVAL OF CORROSION PRODUCTS


E.1.1 Iron, Cast Iron, Steel 75 g sodium hydroxide (NaOH)25 g sodium sulfate (Na2SO4)75 g sodium carbonate (Na2CO3)Reagent water to make 1000 mL

20 to 40 min 20 to 25°C Cathodic treatment with 100 to 200 A/m2 cur-rent density. Use carbon, platinum or stainlesssteel anode.

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TABLE A2.1 Continued


E.1.2 28 mL sulfuric acid (H2SO4, sp gr 1.84)0.5 g inhibitor (diorthotolyl thiourea or



3 min 75°C Cathodic treatment with 2000 A/m2 current den-sity. Use carbon, platinum or lead anode.

E.1.3 100 g diammonium citrate((NH4)2HC6H5O7)


5 min 20 to 25°C Cathodic treatment with 100 A/m2 current den-sity. Use carbon or platinum anode.

E.2.1 Lead and Lead Alloys 28 mL sulfuric acid (H2SO4, sp gr 1.84)0.5 g inhibitor (diorthotolyl thiourea or



3 min 75°C Cathodic treatment with 2000 A/m2 current den-sity. Use carbon, platinum or lead anode.

E.3.1 Copper and CopperAlloys

7.5 g potassium chloride (KCl)Reagent water to make 1000 mL

1 to 3 20 to 25°C Cathodic treatment with 100 A/m2 current den-sity. Use carbon or platinum anode.

E.4.1 Zinc and Cadmium 50 g dibasic sodium phosphate (Na2HPO4)Reagent water to make 1000 mL

5 min 70°C Cathodic treatment with 110 A/m2 current den-sity. Specimen must be energized prior to im-mersion. Use carbon, platinum or stainlesssteel anode.

E.4.2 100 g sodium hydroxide (NaOH)Reagent water to make 1000 mL

1 to 2 min 20 to 25°C Cathodic treatment with 100 A/m2 current den-sity. Specimen must be energized prior to im-mersion. Use carbon, platinum or stainlesssteel anode.

E.5.1 General (excluding Alu-minum, Magnesiumand Tin Alloys)

20 g sodium hydroxide (NaOH)Reagent water to make 1000 mL

5 to 10 min 20 to 25°C Cathodic treatment with 300 A/m2 current den-sity. A S31600 stainless steel anode may beused.

APPENDIXES

(Nonmandatory Information)

X1. DENSITIES FOR A VARIETY OF METALS AND ALLOYS

TABLE X1.1 DENSITIES FOR A VARIETY OF METALS AND ALLOYS

NOTE 1—All UNS numbers that include the letter X indicate a series of numbers under one category.NOTE 2—An asterisk indicates that a UNS number not available.

Aluminum Alloys

UNS Number Alloy Density g/cm3

A91100 1100 2.71A91199 1199 2.70A92024 2024 2.78A92219 2219 2.84A93003 3003 2.73A93004 3004 2.72A95005 5005 2.70A95050 5050 2.69A95052 5052 2.68A95083 5083 2.66A95086 5086 2.66A95154 5154 2.66A95357 5357 2.69A95454 5454 2.69A95456 5456 2.66A96061 6061 2.70* 6062 2.70A96070 6070 2.71A96101 6101 2.70A97075 7075 2.81A97079 7079 2.75A97178 7178 2.83

Stainless SteelsS20100 Type 201 7.94S20200 Type 202 7.94S30200 Type 302 7.94S30400 Type 304 7.94

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TABLE X1.1 Continued

Aluminum Alloys

UNS Number Alloy Density g/cm3

S30403 Type 304L 7.94S30900 Type 309 7.98S31000 Type 310 7.98S31100 Type 311 7.98S31600 Type 316 7.98S31603 Type 316L 7.98S31700 Type 317 7.98S32100 Type 321 7.94S32900 Type 329 7.98N08330 Type 330 7.98S34700 Type 347 8.03S41000 Type 410 7.70S43000 Type 430 7.72S44600 Type 446 7.65S50200 Type 502 7.82

Other Ferrous MetalsF1XXXX Gray cast iron 7.20GXXXXX–KXXXXX Carbon steel 7.86* Silicon iron 7.00KXXXXX Low alloy steels 7.85

Copper AlloysC38600 Copper 8.94C23000 Red brass 230 8.75C26000 Cartridge brass 260 8.52C28000 Muntz metal 280 8.39* Admiralty 442 8.52C44300 Admiralty 443 8.52C44400 Admiralty 444 8.52C44500 Admiralty 445 8.52C68700 Aluminum brass 687 8.33C22000 Commercial bronze 220 8.80C60800 Aluminum bronze, 5 % 608 8.16* Aluminum bronze, 8 % 612 7.78* Composition M 8.45* Composition G 8.77C51000 Phosphor bronze, 5 % 510 8.86C52400 Phosphor bronze, 10 % 524 8.77* 85-5-5-5 8.80C65500 Silicon bronze 655 8.52C70600 Copper nickel 706 8.94C71000 Copper nickel 710 8.94C71500 Copper nickel 715 8.94C75200 Nickel silver 752 8.75

LeadL53305–53405 Antimonial 10.80L5XXXX Chemical 11.33Nickel AlloysN02200 Nickel 200 8.89N04400 Nickel copper 400 8.84N06600 Nickel chromium iron alloy 600 8.51N06625 Nickel chromium molybdenum alloy 625 8.44N08825 Iron nickel chromium alloy 825 8.14N08020 Iron nickel chromium alloy 20 Cb-3 8.08* Iron nickel chromium cast alloy 20 8.02N10665 Nickel molybdenum alloy B2 9.2N10276 Nickel chromium molybdenum alloy

C-2768.8

N06985 Nickel chromium molybdenum alloy G-3 8.3Other Metals

M1XXXX Magnesium 1.74R03600 Molybdenum 10.22P04980 Platinum 21.45P07016 Silver 10.49R05200 Tantalum 16.60L13002 Tin 7.30R50250 Titanium 4.54Z13001 Zinc 7.13R60001 Zirconium 6.53

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X2. CALCULATION OF AVERAGE THICKNESS LOSS RATE OF AN ALLOY WHEN THE DENSITY OF THE CORRODINGMETAL DIFFERS FROM THAT OF THE BULK ALLOY

X2.1 Example

X2.1.1 55% Al-Zn alloy coating on steel sheet exposed for20.95 years at Point Reyes, CA. (As reported in H.E. Townsendand H.H.Lawson, “Twenty-One Year Results for Metallic-Coated Sheet in the ASTM 1976 Atmospheric CorrosionTests”).8

X2.2 Measurements

X2.2.1 Initial aluminum content of coating, C1, as measuredby stripping (Table A1.1, C.3.) and chemical analysis ofuncorroded specimens.

C1 5 55.0% Al (X2.1)

X2.2.2 Time of Exposure, T

T 5 20.95 years5 183 648 hours (X2.2)

X2.2.3 Specimen Area, A

A 5 300 cm2 (X2.3)

X2.2.4 Initial Mass, W1

W1 5 79.3586 g (X2.4)

X2.2.5 Mass after exposure and removal of corrosion prod-ucts according to Table A1.1, C.9.3, W2

W25 78.7660 g (X2.5)

X2.2.6 Mass after removal of remaining coating accordingto Table A1.1, C.3.5, W3

W3 5 75.0810 g (X2.6)

X2.2.7 Aluminum content of remaining uncorroded coatingby chemical analysis of the stripping solution, Cu

Cu 5 57.7% Al (X2.7)

X2.3 Calculations

X2.3.1 Mass loss of corroded coating, W

W5 W1 – W2 5 79.3586 – 78.76605 0.5926 g (X2.8)

X2.3.2 Mass of remaining uncorroded coating, Wu

Wu 5 W2 – W3 5 78.7660 – 75.08105 3.6850 g (X2.9)

X2.3.3 Total mass of original coating, WtWt 5 W1 Wu 5 0.59261 3.68505 4.2776 g (X2.10)

X2.3.4 Composition of corroded coating, C

CW1 CuWu 5 C1Wt (X2.11)

Rearranging gives

C 5 ~C1Wt – CuWu!/W (X2.12)

C 5 ~55.03 4.2776 – 57.73 3.6850!/0.5926 (X2.13)

C 5 38.2 %Al (X2.14)

X2.3.5 The density, D, of a 38.2 % Al-Zn alloy is 4.32g/cm–3. In cases where alloy densities are not known, they canbe estimated by linear interpolation of the component densities.

X2.3.6 Calculate the average thickness loss rate, L (corro-sion rate per Eq 1).

L 5 ~K 3 W!/~A 3 T 3 D! (X2.15)

where K is given in 8.1.2 as 8.763 107

L = (8.763 1073 0.5926)/(3003 183 6483 4.32)L = 0.218 micrometres per year

ASTM International takes no position respecting the validity of any patent rights asserted in connection with any item mentionedin this standard. Users of this standard are expressly advised that determination of the validity of any such patent rights, and the riskof infringement of such rights, are entirely their own responsibility.

This standard is subject to revision at any time by the responsible technical committee and must be reviewed every five years andif not revised, either reapproved or withdrawn. Your comments are invited either for revision of this standard or for additional standardsand should be addressed to ASTM International Headquarters. Your comments will receive careful consideration at a meeting of theresponsible technical committee, which you may attend. If you feel that your comments have not received a fair hearing you shouldmake your views known to the ASTM Committee on Standards, at the address shown below.

This standard is copyrighted by ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959,United States. Individual reprints (single or multiple copies) of this standard may be obtained by contacting ASTM at the aboveaddress or at 610-832-9585 (phone), 610-832-9555 (fax), or [email protected] (e-mail); or through the ASTM website(www.astm.org).

8 Outdoor Atmospheric Corrosion, STP 1421, H. E. Townsend, Ed., AmericanSociety for Testing and MAterials, West Conshohocken, PA, 2002, pp. 284–291.

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LAMPIRAN B

ASTM G31-72

Designation: G 31 – 72 (Reapproved 2004)

Standard Practice forLaboratory Immersion Corrosion Testing of Metals 1

This standard is issued under the fixed designation G 31; the number immediately following the designation indicates the year of originaladoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. A superscriptepsilon (e) indicates an editorial change since the last revision or reapproval.

1. Scope

1.1 This practice2 describes accepted procedures for andfactors that influence laboratory immersion corrosion tests,particularly mass loss tests. These factors include specimenpreparation, apparatus, test conditions, methods of cleaningspecimens, evaluation of results, and calculation and reportingof corrosion rates. This practice also emphasizes the impor-tance of recording all pertinent data and provides a checklistfor reporting test data. Other ASTM procedures for laboratorycorrosion tests are tabulated in the Appendix. (Warning— Inmany cases the corrosion product on the reactive metalstitanium and zirconium is a hard and tightly bonded oxide thatdefies removal by chemical or ordinary mechanical means. Inmany such cases, corrosion rates are established by mass gainrather than mass loss.)

1.2 The values stated in SI units are to be regarded as thestandard. The values given in parentheses are for informationonly.

1.3 This standard does not purport to address all of thesafety concerns, if any, associated with its use. It is theresponsibility of the user of this standard to establish appro-priate safety and health practices and determine the applica-bility of regulatory limitations prior to use.

2. Referenced Documents

2.1 ASTM Standards:3

A 262 Practices for Detecting Susceptibility to Intergranu-lar Attack in Austenitic Stainless Steels

E 8 Test Methods for Tension Testing of Metallic MaterialsG 1 Practice for Preparing, Cleaning, and Evaluating Cor-

rosion Test SpecimensG 4 Guide for Conducting Corrosion Coupon Tests in Field

Applications

G 16 Guide for Applying Statistics to Analysis of CorrosionData

G 46 Guide for Examination and Evaluation of PittingCorrosion

3. Significance and Use

3.1 Corrosion testing by its very nature precludes completestandardization. This practice, rather than a standardized pro-cedure, is presented as a guide so that some of the pitfalls ofsuch testing may be avoided.

3.2 Experience has shown that all metals and alloys do notrespond alike to the many factors that affect corrosion and that“accelerated” corrosion tests give indicative results only, ormay even be entirely misleading. It is impractical to propose aninflexible standard laboratory corrosion testing procedure forgeneral use, except for material qualification tests wherestandardization is obviously required.

3.3 In designing any corrosion test, consideration must begiven to the various factors discussed in this practice, becausethese factors have been found to affect greatly the resultsobtained.

4. Interferences

4.1 The methods and procedures described herein representthe best current practices for conducting laboratory corrosiontests as developed by corrosion specialists in the processindustries. For proper interpretation of the results obtained, thespecific influence of certain variables must be considered.These include:

4.1.1 Metal specimens immersed in a specific hot liquidmay not corrode at the same rate or in the same manner as inequipment where the metal acts as a heat transfer medium inheating or cooling the liquid. If the influence of heat transfereffects is specifically of interest, specialized procedures (inwhich the corrosion specimen serves as a heat transfer agent)must be employed (1).4

4.1.2 In laboratory tests, the velocity of the environmentrelative to the specimens will normally be determined byconvection currents or the effects induced by aeration orboiling or both. If the specific effects of high velocity are to bestudied, special techniques must be employed to transfer the

1 This practice is under the jurisdiction of ASTM Committee G01 on Corrosionof Metals and is the direct responsibility of Subcommittee G01.05 on LaboratoryCorrosion Tests.

Current edition approved May 1, 2004. Published May 2004. Originallyapproved in 1972. Last previous edition approved in 1998 as G 31 – 72 (1998).

2 This practice is based upon NACE Standard TM-01-69, “Test Method-Laboratory Corrosion Testing of Metals for the Process Industries,” with modifica-tions to relate more directly to Practices G 1 and G 31 and Guide G 4.

3 For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Customer Service at [email protected]. ForAnnual Book of ASTMStandardsvolume information, refer to the standard’s Document Summary page onthe ASTM website.

4 The boldface numbers in parentheses refer to the list of references at the end ofthis practice.

1

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environment through tubular specimens or to move it rapidlypast the plane face of a corrosion coupon (2). Alternatively, thecoupon may be rotated through the environment, although it isthen difficult to evaluate the velocity quantitatively because ofthe stirring effects incurred.

4.1.3 The behavior of certain metals and alloys may beprofoundly influenced by the presence of dissolved oxygen. Ifthis is a factor to be considered in a specific test, the solutionshould be completely aerated or deaerated in accordance with8.7.

4.1.4 In some cases, the rate of corrosion may be governedby other minor constituents in the solution, in which case theywill have to be continually or intermittently replenished bychanging the solution in the test.

4.1.5 Corrosion products may have undesirable effects on achemical product. The amount of possible contamination canbe estimated from the loss in mass of the specimen, with properapplication of the expected relationships among (1) the area ofcorroding surface, (2) the mass of the chemical producthandled, and (3) the duration of contact of a unit of mass of thechemical product with the corroding surface.

4.1.6 Corrosion products from the coupon may influence thecorrosion rate of the metal itself or of different metals exposedat the same time. For example, the accumulation of cupric ionsin the testing of copper alloys in intermediate strengths ofsulfuric acid will accelerate the corrosion of copper alloys, ascompared to the rates that would be obtained if the corrosionproducts were continually removed. Cupric ions may alsoexhibit a passivating effect upon stainless steel coupons ex-posed at the same time. In practice, only alloys of the samegeneral type should be exposed in the testing apparatus.

4.1.7 Coupon corrosion testing is predominantly designedto investigate general corrosion. There are a number of otherspecial types of phenomena of which one must be aware in thedesign and interpretation of corrosion tests.

4.1.7.1 Galvanic corrosion may be investigated by specialdevices which couple one coupon to another in electricalcontact. The behavior of the specimens in this galvanic coupleare compared with that of insulated specimens exposed on thesame holder and the galvanic effects noted. It should beobserved, however, that galvanic corrosion can be greatlyaffected by the area ratios of the respective metals, the distancebetween the metals and the resistivity of the electrolyte. Thecoupling of corrosion coupons then yields only qualitativeresults, as a particular coupon reflects only the relationshipbetween these two metals at the particular area ratio involved.

4.1.7.2 Crevice corrosion or concentration cell corrosionmay occur where the metal surface is partially blocked fromthe corroding liquid as under a spacer or supporting hook. It isnecessary to evaluate this localized corrosion separately fromthe overall mass loss.

4.1.7.3 Selective corrosion at the grain boundaries (forexample, intergranular corrosion of sensitized austenitic stain-less steels) will not be readily observable in mass lossmeasurements unless the attack is severe enough to cause graindropping, and often requires microscopic examination of thecoupons after exposure.

4.1.7.4 Dealloying or “parting” corrosion is a condition inwhich one constituent is selectively removed from an alloy, asin the dezincification of brass or the graphitization of cast iron.Close attention and a more sophisticated evaluation than asimple mass loss measurement are required to detect thisphenomenon.

4.1.7.5 Certain metals and alloys are subject to a highlylocalized type of attack called pitting corrosion. This cannot beevaluated by mass loss alone. The reporting of nonuniformcorrosion is discussed below. It should be appreciated thatpitting is a statistical phenomenon and that the incidence ofpitting may be directly related to the area of metal exposed. Forexample, a small coupon is not as prone to exhibit pitting as alarge one and it is possible to miss the phenomenon altogetherin the corrosion testing of certain alloys, such as the AISI Type300 series stainless steels in chloride contaminated environ-ments.

4.1.7.6 All metals and alloys are subject to stress-corrosioncracking under some circumstances. This cracking occursunder conditions of applied or residual tensile stress, and itmay or may not be visible to the unaided eye or upon casualinspection. A metallographic examination may confirm thepresence of stress-corrosion cracking. It is imperative to notethat this usually occurs with no significant loss in mass of thetest coupon, although certain refractory metals are an exceptionto these observations. Generally, if cracking is observed on thecoupon, it can be taken as positive indication of susceptibility,whereas failure to effect this phenomenon simply means that itdid not occur under the duration and specific conditions of thetest. Separate and special techniques are employed for thespecific evaluation of the susceptibility of metals and alloys tostress corrosion cracking (see Ref.(3)).

5. Apparatus

5.1 A versatile and convenient apparatus should be used,consisting of a kettle or flask of suitable size (usually 500 to5000 mL), a reflux condenser with atmospheric seal, a spargerfor controlling atmosphere or aeration, a thermowell andtemperature-regulating device, a heating device (mantle, hotplate, or bath), and a specimen support system. If agitation isrequired, the apparatus can be modified to accept a suitablestirring mechanism, such as a magnetic stirrer. A typical resinflask setup for this type test is shown in Fig. 1.

5.2 The suggested components can be modified, simplified,or made more sophisticated to fit the needs of a particularinvestigation. The suggested apparatus is basic and the appa-ratus is limited only by the judgment and ingenuity of theinvestigator.

5.2.1 A glass reaction kettle can be used where the configu-ration and size of the specimen will permit entry through thenarrow kettle neck (for example, 45/50 ground-glass joint). Forsolutions corrosive to glass, suitable metallic or plastic kettlesmay be employed.

5.2.2 In some cases a wide-mouth jar with a suitable closureis sufficient when simple immersion tests at ambient tempera-tures are to be investigated.

5.2.3 Open-beaker tests should not be used because ofevaporation and contamination.

G 31 – 72 (2004)

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5.2.4 In more complex tests, provisions might be needed forcontinuous flow or replenishment of the corrosive liquid, whilesimultaneously maintaining a controlled atmosphere.

6. Sampling

6.1 The bulk sampling of products is outside the scope ofthis practice.

7. Test Specimen

7.1 In laboratory tests, uniform corrosion rates of duplicatespecimens are usually within610 % under the same testconditions. Occasional exceptions, in which a large differenceis observed, can occur under conditions of borderline passivityof metals or alloys that depend on a passive film for theirresistance to corrosion. Therefore, at least duplicate specimensshould normally be exposed in each test.

7.2 If the effects of corrosion are to be determined bychanges in mechanical properties, untested duplicate speci-mens should be preserved in a noncorrosive environment at thesame temperature as the test environment for comparison withthe corroded specimens. The mechanical property commonlyused for comparison is the tensile strength. Measurement ofpercent elongation is a useful index of embrittlement. Theprocedures for determining these values are shown in detail inTest Methods E 8.

7.3 The size and shape of specimens will vary with thepurpose of the test, nature of the materials, and apparatus used.A large surface-to-mass ratio and a small ratio of edge area tototal area are desirable. These ratios can be achieved throughthe use of square or circular specimens of minimum thickness.Masking may also be used to achieve the desired area ratios butmay cause crevice corrosion problems. Circular specimensshould preferably be cut from sheet and not bar stock, tominimize the exposed end grain. Special coupons (for example,sections of welded tubing) may be employed for specificpurposes.

7.3.1 A circular specimen of about 38-mm (1.5-in.) diam-eter is a convenient shape for laboratory corrosion tests. Witha thickness of approximately 3 mm (0.125-in.) and an 8-mm(5⁄16-in.) or 11-mm (7⁄16-in.) diameter hole for mounting, thesespecimens will readily pass through a 45/50 ground-glass jointof a distillation kettle. The total surface area of a circularspecimen is given by the following equation:

A 5 p/2~D 2 2 d 2! 1 tpD 1 tpd (1)

where:t = thickness,D = diameter of the specimen, andd = diameter of the mounting hole.

7.3.1.1 If the hole is completely covered by the mountingsupport, the last term (tpd) in the equation is omitted.

7.3.2 Strip coupons 50 by 25 by 1.6 or 3 mm (2 by 1 by1⁄16

or 1⁄8 in.) may be preferred as corrosion specimens, particularlyif interface or liquid line effects are to be studied by thelaboratory tests (see Fig. 1), but the evaluation of such specificeffects are beyond the scope of this practice.

7.3.3 All specimens should be measured carefully to permitaccurate calculation of the exposed areas. A geometric areacalculation accurate to61 % is usually adequate.

7.4 More uniform results may be expected if a substantiallayer of metal is removed from the specimens to eliminatevariations in condition of the original metallic surface. This canbe done by chemical treatment (pickling), electrolytic removal,or by grinding with a coarse abrasive paper or cloth such as No.50, using care not to work harden the surface (see section 5.7).At least 0.0025 mm (0.0001 in.) or 0.0155 to 0.0233 mg/mm2

(10 to 15 mg/in.2) should be removed. (If clad alloy specimensare to be used, special attention must be given to ensure thatexcessive metal is not removed.) After final preparation of thespecimen surface, the specimens should be stored in a desic-cator until exposure, if they are not used immediately. Inspecial cases (for example, for aluminum and certain copperalloys), a minimum of 24 h storage in a desiccator is recom-mended. The choice of a specific treatment must be consideredon the basis of the alloy to be tested and the reasons for testing.A commercial surface may sometimes yield the most signifi-cant results. Too much surface preparation may remove segre-gated elements, surface contamination, and so forth, andtherefore not be representative.

7.5 Exposure of sheared edges should be avoided unless thepurpose of the test is to study effects of the shearing operation.It may be desirable to test a surface representative of thematerial and metallurgical conditions used in practice.

NOTE 1—The flask can be used as a versatile and convenient apparatusto conduct simple immersion tests. Configuration of top to flask is suchthat more sophisticated apparatus can be added as required by the specifictest being conducted.A = thermowell,B = resin flask,C = specimens hungon supporting device,D = air inlet, E = heating mantle,F = liquid inter-face,G = opening in flask for additional apparatus that may be required,andH = reflux condenser.

FIG. 1 Typical Resin Flask

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7.6 The specimen can be stamped with an appropriateidentifying mark. If metallic contamination of the stamped areamay influence the corrosion behavior, chemical cleaning mustbe employed to remove any traces of foreign particles from thesurface of the coupon (for example, by immersion of stainlesssteel coupons in dilute nitric acid following stamping with steeldies).

7.6.1 The stamp, besides identifying the specimen, intro-duces stresses and cold work in the specimen that could beresponsible for localized corrosion or stress-corrosion crack-ing, or both.

7.6.2 Stress-corrosion cracking at the identifying mark is apositive indication of susceptibility to such corrosion. How-ever, the absence of cracking should not be interpreted asindicating resistance (see 4.1.7.6).

7.7 Final surface treatment of the specimens should includefinishing with No. 120 abrasive paper or cloth or the equiva-lent, unless the surface is to be used in the mill finishedcondition. This resurfacing may cause some surface workhardening, to an extent which will be determined by the vigorof the surfacing operation, but is not ordinarily significant. Thesurface finish to be encountered in service may be moreappropriate for some testing.

7.7.1 Coupons of different alloy compositions should neverbe ground on the same cloth.

7.7.2 Wet grinding should be used on alloys which workharden quickly, such as the austenitic stainless steels.

7.8 The specimens should be finally degreased by scrubbingwith bleach-free scouring powder, followed by thorough rins-ing in water and in a suitable solvent (such as acetone,methanol, or a mixture of 50 % methanol and 50 % ether), andair dried. For relatively soft metals (such as aluminum,magnesium, and copper), scrubbing with abrasive powder isnot always needed and can mar the surface of the specimen.Proper ultrasonic procedures are an acceptable alternate. Theuse of towels for drying may introduce an error throughcontamination of the specimens with grease or lint.

7.9 The dried specimens should be weighed on an analyticalbalance to an accuracy of at least60.5 mg. If cleaning deposits(for example, scouring powder) remain or lack of completedryness is suspected, then recleaning and drying is performeduntil a constant mass is attained.

7.10 The method of specimen preparation should be de-scribed when reporting test results, to facilitate interpretationof data by other persons.

7.11 The use of welded specimens is sometimes desirable,because some welds may be cathodic or anodic to the parentmetal and may affect the corrosion rate.

7.11.1 The heat-affected zone is also of importance butshould be studied separately, because welds on coupons do notfaithfully reproduce heat input or size effects of full-sizeweldments.

7.11.2 Corrosion of a welded coupon is best reported bydescription and thickness measurements rather than a millime-tre per year (mils per year) rate, because the attack is normallylocalized and not representative of the entire surface.

7.11.3 A complete discussion of corrosion testing of weldedcoupons or the effect of heat treatment on the corrosionresistance of a metal is not within the scope of this practice.

8. Test Conditions

8.1 Selection of the conditions for a laboratory corrosiontest will be determined by the purpose of the test.

8.1.1 If the test is to be a guide for the selection of a materialfor a particular purpose, the limits of the controlling factors inservice must be determined. These factors include oxygenconcentration, temperature, rate of flow, pH value, composi-tion, and other important characteristics of the solution.

8.2 An effort should be made to duplicate all pertinentservice conditions in the corrosion test.

8.3 It is important that test conditions be controlled through-out the test in order to ensure reproducible results.

8.4 The spread in corrosion rate values for duplicate speci-mens in a given test probably should not exceed610 % of theaverage when the attack is uniform.

8.5 Composition of Solution:8.5.1 Test solutions should be prepared accurately from

chemicals conforming to the Specifications of the Committeeon Analytical Reagents of the American Chemical Society5 anddistilled water, except in those cases where naturally occurringsolutions or those taken directly from some plant process areused.

8.5.2 The composition of the test solutions should becontrolled to the fullest extent possible and should be describedas completely and as accurately as possible when the results arereported.

8.5.2.1 Minor constituents should not be overlooked be-cause they often affect corrosion rates.

8.5.2.2 Chemical content should be reported as percentageby weight of the solutions. Molarity and normality are alsohelpful in defining the concentration of chemicals in some testsolutions.

8.5.3 If problems are suspected, the composition of the testsolutions should be checked by analysis at the end of the testto determine the extent of change in composition, such asmight result from evaporation or depletion.

8.5.4 Evaporation losses may be controlled by a constantlevel device or by frequent addition of appropriate solution tomaintain the original volume within61 %. Preferably, the useof a reflux condenser ordinarily precludes the necessity ofadding to the original kettle charge.

8.5.5 In some cases, composition of the test solution maychange as a result of catalytic decomposition or by reactionwith the test coupons. These changes should be determined ifpossible. Where required, the exhausted constituents should beadded or a fresh solution provided during the course of the test.

8.5.6 When possible, only one type of metal should beexposed in a given test (see 4.1.6).

5 Reagent Chemicals, American Chemical Society Specifications, AmericanChemical Society, Washington, DC. For suggestions on the testing of reagents notlisted by the American Chemical Society, seeAnalar Standards for LaboratoryChemicals, BDH Ltd., Poole, Dorset, U.K., and theUnited States Pharmacopeiaand National Formulary, U.S. Pharmacopeial Convention, Inc. (USPC), Rockville,MD.

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8.6 Temperature of Solution:8.6.1 Temperature of the corroding solution should be

controlled within 61°C (61.8°F) and must be stated in thereport of test results.

8.6.2 If no specific temperature, such as boiling point, isrequired or if a temperature range is to be investigated, theselected temperatures used in the test, and their respectiveduration, must be reported.

8.6.3 For tests at ambient temperature, the tests should beconducted at the highest temperature anticipated for stagnantstorage in summer months. This temperature may be as high asfrom 40 to 45°C (104 to 113°F) in some areas. The variation intemperature should be reported also (for example, 406 2°C).

8.7 Aeration of Solution:8.7.1 Unless specified, the solution should not be aerated.

Most tests related to process equipment should be run with thenatural atmosphere inherent in the process, such as the vaporsof the boiling liquid.

8.7.2 If aeration is employed, the specimen should not belocated in the direct air stream from the sparger. Extraneouseffects can be encountered if the air stream impinges on thespecimens.

8.7.3 If exclusion of dissolved oxygen is necessary, specifictechniques are required, such as prior heating of the solutionand sparging with an inert gas (usually nitrogen). A liquidatmospheric seal is required on the test vessel to prevent furthercontamination.

8.7.4 If oxygen saturation of the test solution is desired, thiscan best be achieved by sparging with oxygen. For otherdegrees of aeration, the solution should be sparaged with air orsynthetic mixtures of air or oxygen with an inert gas. Oxygensaturation is a function of the partial pressure of oxygen in thegas.

8.8 Solution Velocity:8.8.1 The effect of velocity is not usually determined in

normal laboratory tests, although specific tests have beendesigned for this purpose.

8.8.2 Tests at the boiling point should be conducted with theminimum possible heat input, and boiling chips should be usedto avoid excessive turbulence and bubble impingement.

8.8.3 In tests below the boiling point, thermal convectiongenerally is the only source of liquid velocity.

8.8.4 In test solutions with high viscosity, supplementalcontrolled stirring with a magnetic stirrer is recommended.

8.9 Volume of Test Solution:8.9.1 The volume of the test solution should be large enough

to avoid any appreciable change in its corrosivity during thetest, either through exhaustion of corrosive constituents or byaccumulation of corrosion products that might affect furthercorrosion.

8.9.2 Two examples of a minimum “solution volume-tospecimen area” ratio are 0.20 mL/mm2 (125 mL/in.2) ofspecimen surface (Practice A 262), and 0.40 mL/mm2 (250mL/in.2).

8.9.3 When the test objective is to determine the effect of ametal or alloy on the characteristics of the test solution (forexample, to determine the effects of metals on dyes), it isdesirable to reproduce the ratio of solution volume to exposed

metal surface that exists in practice. The actual time of contactof the metal with the solution must also be taken into account.Any necessary distortion of the test conditions must beconsidered when interpreting the results.

8.10 Method of Supporting Specimens:8.10.1 The supporting device and container should not be

affected by or cause contamination of the test solution.8.10.2 The method of supporting specimens will vary with

the apparatus used for conducting the test, but should bedesigned to insulate the specimens from each other physicallyand electrically and to insulate the specimens from any metalliccontainer or supporting device used within the apparatus.

8.10.3 Shape and form of the specimen support shouldassure free contact of the specimen with the corroding solution,the liquid line, or the vapor phase as shown in Fig. 1. If cladalloys are exposed, special procedures will be required toensure that only the cladding is exposed, unless the purpose isto test the ability of the cladding to protect cut edges in the testsolution.

8.10.4 Some common supports are glass or ceramic rods,glass saddles, glass hooks, fluorocarbon plastic strings, andvarious insulated or coated metallic supports.

8.11 Duration of Test:8.11.1 Although duration of any test will be determined by

the nature and purpose of the test, an excellent procedure forevaluating the effect of time on corrosion of the metal and alsoon the corrosiveness of the environment in laboratory tests hasbeen presented by Wachter and Treseder(4). This technique iscalled the “planned interval test,” and the procedure andevaluation of results are given in Table 1. Other procedures thatrequire the removal of solid corrosion products betweenexposure periods will not measure accurately the normalchanges of corrosion with time.

8.11.2 Materials that experience severe corrosion generallydo not ordinarily need lengthy tests to obtain accurate corro-sion rates. However, there are cases where this assumption isnot valid. For example, lead exposed to sulfuric acid corrodesat an extremely high rate at first, while building a protectivefilm; then the rates decrease considerably so that furthercorrosion is negligible. The phenomenon of forming a protec-tive film is observed with many corrosion-resistant materials.Therefore, short tests on such materials would indicate a highcorrosion rate and be completely misleading.

8.11.3 Short-time tests also can give misleading results onalloys that form passive films, such as stainless steels. Withborderline conditions, a prolonged test may be needed topermit breakdown of the passive film and subsequent morerapid attack. Consequently, tests run for long periods areconsiderably more realistic than those conducted for shortdurations. This statement must be qualified by stating thatcorrosion should not proceed to the point where the originalspecimen size or the exposed area is drastically reduced orwhere the metal is perforated.

8.11.4 If anticipated corrosion rates are moderate or low, thefollowing equation gives the suggested test duration:

Hours5 2000/~corrosion rate in mpy! (2)

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where mpy = mils per year (see 11.2.1 and Note 1 forconversion to other units).

8.11.4.1Example—Where the corrosion rate is 0.25 mm/y(10 mpy), the test should run for at least 200 h.

8.11.4.2 This method of estimating test duration is usefulonly as an aid in deciding, after a test has been made, whetheror not it is desirable to repeat the test for a longer period. Themost common testing periods are 48 to 168 h (2 to 7 days).

8.11.5 In some cases, it may be necessary to know thedegree of contamination caused by the products of corrosion.This can be accomplished by analysis of the solution aftercorrosion has occurred. The corrosion rate can be calculatedfrom the concentration of the matrix metal found in thesolution and it can be compared to that determined from themass loss of the specimens. However, some of the corrosionproducts usually adhere to the specimen as a scale and thecorrosion rate calculated from the metal content in the solutionis not always correct.

8.12 The design of corrosion testing programs is furtherdiscussed in Guide G 16.

9. Methods of Cleaning Specimens after Test

9.1 Before specimens are cleaned, their appearance shouldbe observed and recorded. Location of deposits, variations intypes of deposits, or variations in corrosion products areextremely important in evaluating localized corrosion, such aspitting and concentration cell attack.

9.2 Cleaning specimens after the test is a vital step in thecorrosion test procedure and if not done properly, can causemisleading results.

9.2.1 Generally, the cleaning procedure should remove allcorrosion products from specimens with a minimum removalof sound metal.

9.2.2 Set rules cannot be applied to specimen cleaning,because procedures will vary, depending on the type of metalbeing cleaned and on the degree of adherence of corrosionproducts.

9.3 Cleaning methods can be divided into three generalcategories: mechanical, chemical, and electrolytic.

9.3.1 Mechanical cleaning includes scrubbing, scraping,brushing, mechanical shocking, and ultrasonic procedures.Scrubbing with a bristle brush and mild abrasive is the mostpopular of these methods. The others are used principally as asupplement to remove heavily encrusted corrosion productsbefore scrubbing. Care should be used to avoid the removal ofsound metal.

9.3.2 Chemical cleaning implies the removal of materialfrom the surface of the specimen by dissolution in an appro-priate chemical solution. Solvents such as acetone, carbontetrachloride, and alcohol are used to remove oil, grease, orresin and are usually applied prior to other methods ofcleaning. Chemicals are chosen for application to a specificmaterial. Methods for chemical cleaning after testing of spe-cific metals and alloys are described in Practice G 1.

9.3.3 Electrolytic cleaning should be preceded by scrubbingto remove loosely adhering corrosion products. A method ofelectrolytic cleaning is described in Practice G 1.

9.3.3.1 Precautions must be taken to ensure good electricalcontact with the specimen, to avoid contamination of thesolution with easily reducible metal ions, and to ensure thatinhibitor decomposition has not occurred.

9.4 Whatever treatment is used to clean specimens after acorrosion test, its effect in removing metal should be deter-mined and the mass loss should be corrected accordingly. A“blank” specimen should be weighed before and after exposureto the cleaning procedure to establish this mass loss (see alsoPractice G 1). Careful observation is needed to ensure thatpitting does not occur during cleaning.

9.4.1 Following removal of all scale, the specimen shouldbe treated as discussed in 5.8.

9.4.2 The description of the cleaning method should beincluded with the data reported.

10. Interpretation of Results

10.1 After corroded specimens have been cleaned, theyshould be reweighed with an accuracy corresponding to that ofthe original weighing. The mass loss during the test period canbe used as the principal measure of corrosion.

TABLE 1 Planned Interval Corrosion Test(Reprinted by permission from Chemical Engineering Progress, June

1947)Identical specimens all placed in the same corrosive fluid. Imposed

conditions of the test kept constant for entire time t + 1. Letters, A1, At, At+1, B, represent corrosion damage experienced by each test

specimen. A2 is calculated by subtracting Atfrom At+1.

Occurrences During Corrosion Test Criteria

Liquid corrosiveness unchangeddecreasedincreased

A1 = BB < A1

A1 < B

Metal corrodibility unchangeddecreasedincreased

A2 = BA2 < BB < A2

Combinations of Situations

Liquid corrosiveness Metal corrodibility Criteria

1. unchanged unchanged A1 = A2 = B2. unchanged decreased A2 < A1 = B3. unchanged increased A1 = B < A2

4. decreased unchanged A2 = B < A1

5. decreased decreased A2 < B < A1

6. decreased increased A1 > B < A2

7. increased unchanged A1 < A2 = B8. increased decreased A1 < B > A2

9. increased increased A1 < B < A2

Example; Conditions: Duplicate strips of low-carbon steel, each 19 by 76 mm(3⁄4 by 3 in.), immersed in 200 mL of 10 % AlCl3-90 % SbCl3 mixture throughwhich dried HCl gas was slowly bubbled at atmospheric pressure. Temperature90°C.

Interval,days

Mass Loss,mg

Penetration,mm (mils)

ApparentCorrosion

Rate, mm/y(mpy)

A1 0–1 1080 .043 (1.69) 15.7 (620)At 0–3 1430 .057 (2.24) 6.9 (270)At+1 0–4 1460 .058 (2.29) 5.3 (210)B 3–4 70 .003 (0.11) 1.0 (40)A2 calc. 3–4 30 .001 (0.05) 0.5 (18)

Example: A2 < B < A1

.001 < .003 < .043 (0.05 < 0.11 < 1.69)Therefore, liquid markedly decreased in corrosiveness during test, and formationof partially protective scale on the steel was indicated.

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10.2 After the specimens have been reweighed, they shouldbe examined carefully for the presence of any pits. If there areany pits, the average and maximum depths of pits are deter-mined with a pit gage or a calibrated microscope which can befocused first on the edges and then on the bottoms of the pits.The degree of lateral spreading of pits may also be noted.

10.2.1 Pit depths should be reported in millimetres orthousandths of an inch for the test period and not interpolatedor extrapolated to millimetres per year, thousandths of an inchper year, or any other arbitrary period because rarely, if ever, isthe rate of initiation or propagation of pits uniform.

10.2.2 The size, shape, and distribution of pits should benoted. A distinction should be made between those occurringunderneath the supporting devices (concentration cells) andthose on the surfaces that were freely exposed to the testsolution (see Guide G 46).

10.3 If the material being tested is suspected of beingsubject to dealloying forms of corrosion such as dezincificationor to intergranular attack, a cross section of the specimenshould be microscopically examined for evidence of suchattack.

10.4 The specimen may be subjected to simple bending teststo determine whether any embrittlement attack has occurred.

10.5 It may be desirable to make quantitative mechanicaltests, comparing the exposed specimens with uncorrodedspecimens reserved for the purpose, as described in 7.2.

11. Calculating Corrosion Rates

11.1 Calculating corrosion rates requires several pieces ofinformation and several assumptions:

11.1.1 The use of corrosion rates implies that all mass losshas been due to general corrosion and not to localizedcorrosion, such as pitting or intergranular corrosion of sensi-tized areas on welded coupons. Localized corrosion is reportedseparately.

11.1.2 The use of corrosion rates also implies that thematerial has not been internally attacked as by dezincificationor intergranular corrosion.

11.1.3 Internal attack can be expressed as a corrosion rate ifdesired. However, the calculations must not be based on massloss (except in qualification tests such as Practices A 262),which is usually small but on microsections which show depthof attack.

11.2 Assuming that localized or internal corrosion is notpresent or is recorded separately in the report, the averagecorrosion rate can be calculated by the following equation:

Corrosion rate5 ~K 3 W!/~A 3 T 3 D! (3)

where:K = a constant (see below)T = time of exposure in hours to the nearest 0.01 h,A = area in cm2 to the nearest 0.01 cm2,W = mass loss in g, to nearest 1 mg (corrected for any loss

during cleaning (see 9.4)), andD = density in g/cm3, (see Appendix X1 of Practice G 1).

11.2.1 Many different units are used to express corrosionrates. Using the above units forT, A, W, andD, the corrosionrate can be calculated in a variety of units with the followingappropriate value ofK:

Corrosion Rate Units DesiredConstant (K) in Corrosion

Rate Equationmils per year (mpy) 3.45 3 106

inches per year (ipy) 3.45 3 103

inches per month (ipm) 2.87 3 102

millimetres per year (mm/y) 8.76 3 104

micrometres per year (µm/y) 8.76 3 107

picometres per second (pm/s) 2.78 3 106

grams per square metre per hour (g/m2·h) 1.00 3 104 3 DA

milligrams per square decimetre per day (mdd) 2.40 3 106 3 DA

micrograms per square metre per second (µg/m2·s)

2.78 3 106 3 DA

___________

A Density is not needed to calculate the corrosion rate in these units. The densityin the constant K cancels out the density in the corrosion rate equation.

NOTE 1—If desired, these constants may also be used to convertcorrosion rates from one set of units to another. To convert a corrosion ratein units X to a rate of unitsY, multiply by KY/KX for example:

15 mpy5 153 [~2.783 106!/~~3.453 106!#pm/s

5 12.1 pm/s (4)

12. Report

12.1 The importance of reporting all data as completely aspossible cannot be overemphasized.

12.2 Expansion of the testing program in the future orcorrelating the results with tests of other investigators will bepossible only if all pertinent information is properly recorded.

12.3 The following checklist is a recommended guide forreporting all important information and data.

12.3.1 Corrosive media and concentration (any changesduring test).

12.3.2 Volume of test solution.12.3.3 Temperature (maximum, minimum, average).12.3.4 Aeration (describe conditions or technique).12.3.5 Agitation (describe conditions or technique).12.3.6 Type of apparatus used for test.12.3.7 Duration of each test.12.3.8 Chemical composition or trade name of metals

tested.12.3.9 Form and metallurgical conditions of specimens.12.3.10 Exact size, shape, and area of specimens.12.3.11 Treatment used to prepare specimens for test.12.3.12 Number of specimens of each material tested, and

whether specimens were tested separately or which specimenstested in the same container.

12.3.13 Method used to clean specimens after exposure andthe extent of any error expected by this treatment.

12.3.14 Initial and final masses and actual mass losses foreach specimen.

12.3.15 Evaluation of attack if other than general, such ascrevice corrosion under support rod, pit depth and distribution,and results of microscopical examination or bend tests.

12.3.16 Corrosion rates for each specimen.

G 31 – 72 (2004)

7

12.4 Minor occurrences or deviations from the proposed testprogram often can have significant effects and should bereported if known.

12.5 Statistics can be a valuable tool for analyzing theresults from test programs designed to generate adequate data.Excellent references for the use of statistics in corrosion studiesinclude Ref.(5-7) and in Guide G 16.

13. Keywords

13.1 accelerated; immersion; laboratory; mass loss; metals;pitting

REFERENCES

(1) Fisher, A. O., and Whitney, Jr., F. L., “Laboratory Methods forDetermining Corrosion Rates Under Heat Flux Conditions,”Corro-sion, Vol 15, No. 5, May 1959, p. 257t.

(2) U.S. Patent 3,228,236, 1969.(3) “Stress Corrosion Test Environments and Test Durations,”Symposium

on Stress Corrosion Testing, ASTM STP 425, ASTM, 1967.(4) Wachter, A., and Treseder, R. S., “Corrosion Testing Evaluation of

Metals for Process Equipment,”Chemical Engineering Progress, Vol43, June 1947, pp. 315–326.

(5) Mickley, H. S., Sherwood, T. K., and Reed, C. E. editors,Applied

Mathematics in Chemical Engineering2nd Edition, McGraw-HillBook Co., New York, NY 1957.

(6) Youden, W. J.,Experimentation and Measurement, National ScienceTeachers Assn., Washington, DC, 1962.

(7) Booth, F. F., and Tucker, G. E. G., “Statistical Distribution ofEndurance in Electrochemical Stress-Corrosion Tests,”Corrosion, Vol21, No. 5, May 1965, pp. 173–177.

(8) Champion, F. A.,Corrosion Testing Procedures, 2nd Edition, JohnWiley & Sons, Inc., New York, NY, 1965.

ASTM International takes no position respecting the validity of any patent rights asserted in connection with any item mentionedin this standard. Users of this standard are expressly advised that determination of the validity of any such patent rights, and the riskof infringement of such rights, are entirely their own responsibility.

This standard is subject to revision at any time by the responsible technical committee and must be reviewed every five years andif not revised, either reapproved or withdrawn. Your comments are invited either for revision of this standard or for additional standardsand should be addressed to ASTM International Headquarters. Your comments will receive careful consideration at a meeting of theresponsible technical committee, which you may attend. If you feel that your comments have not received a fair hearing you shouldmake your views known to the ASTM Committee on Standards, at the address shown below.

This standard is copyrighted by ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959,United States. Individual reprints (single or multiple copies) of this standard may be obtained by contacting ASTM at the aboveaddress or at 610-832-9585 (phone), 610-832-9555 (fax), or [email protected] (e-mail); or through the ASTM website(www.astm.org).

G 31 – 72 (2004)

8

LAMPIRAN C

API 570

54 API 570

Refer to API 576 for additional information on PRD pop test results and investigations.

7 Inspection Data Evaluation, Analysis, and Recording

7.1 Corrosion Rate Determination

7.1.1 General

The owner/user may use either the Point-to-Point analysis method or a statistical analysis method, or a combination

of both, to determine the long term or short time corrosion rates.

7.1.2 Point-to-Point Method

The Long Term (LT) corrosion rate of an individual CML shall be calculated from the following formula:

(1)

The Short Term (ST) corrosion rate of an individual CML shall be calculated from the following formula:

where

tinitial is the thickness, in inches (millimeters), at the same location as tactual measured at initial installation

or at the commencement of a new corrosion rate environment;

tprevious is the thickness, in inches (millimeters), at the same location as tactual measured during one or more

previous inspections.

LT and ST corrosion rates should be compared to see which results in the shortest remaining life as part of the data

assessment. The authorized inspector, in consultation with a corrosion specialist, shall select the corrosion rate that

best reflects the current process (see 6.3.3 for inspection interval determination).

7.1.3 Statistical Analysis Method

The Owner–User may elect to use a statistical analysis method (e.g. probability plots or related tools) to establish a

representative corrosion, remaining life estimate and/or re-inspection date. Any statistical approach shall be

documented. Care shall be taken to ensure that the statistical treatment of data results reflects a reasonably

conservative representation of the various pipe components within the circuit. Statistical analysis employing point

measurements is not applicable to piping circuits with significant localized unpredictable corrosion mechanisms (See

additional notes and statistical analysis in 6.5). There are many statistical tools that can be employed once Piping

Circuits have been properly established. While such calculations offer a convenient means to numerically summarize

Circuit data, it is often the combination of descriptive statistics plus data visualization through statistical plots that

provide the most useful results.

See API 574 for additional discussion on statistical analysis methods.

7.2 Remaining Life Calculations

The remaining life shall be calculated from the following formula:

(2)

Corrosion rate LT( )tinitial tactual–

time years( ) between tinitial and tactual

------------------------------------------------------------------------------------------------------=

Corrosion rate ST( )tinitial tactual–

time years( ) between tprevious and tactual

------------------------------------------------------------------------------------------------------------=

Remaining life years( )tactual trequired–

corrosion rate inches mm( ) per year[ ]--------------------------------------------------------------------------------------------------------------=

Copyright American Petroleum Institute

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asus

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PIPING INSPECTION CODE: IN-SERVICE INSPECTION, RATING, REPAIR, AND ALTERATION OF PIPING SYSTEMS 55

where

tactual is the actual thickness, in inches (millimeters), measured at the time of inspection for a given location

or component as specified in 5.7.

trequired is the required thickness, in inches (millimeters), at the same location or component as the actual

measurement computed by the design formulas (e.g. pressure and structural) before corrosion

allowance and manufacturer's tolerance are added.

7.3 Newly Installed Piping Systems or Changes in Service

For new piping systems and piping systems for which service conditions are being changed, one of the following

methods shall be employed to determine the probable rate of corrosion from which the remaining wall thickness at the

time of the next inspection can be estimated.

a) A corrosion rate for a piping circuit may be calculated from data collected by the owner/user on piping systems of

similar material in comparable service and comparable operating conditions.

b) If data for the same or similar service are not available, a corrosion rate for a piping circuit may be estimated from

the owner/user's experience or from published data on piping systems in comparable service.

c) If the probable corrosion rate cannot be determined by either method listed in 7.3a) or 7.3b), the initial thickness

measurement determinations shall be made after no more than three months of service by using nondestructive

thickness measurements of the piping system. Corrosion monitoring devices, such as corrosion coupons or

corrosion probes, may be useful in establishing the timing of these thickness measurements. Subsequent

measurements shall be made after appropriate intervals until the corrosion rate is established.

7.4 Existing and Replacement Piping

Corrosion rates shall be calculated on one of the methods identified in 7.1. For repaired or in-kind replacement piping,

the corrosion rate shall be established based on the previous worse case measured rate at the replacement location

or the circuit average rate.

If calculations indicate that an inaccurate rate of corrosion has been assumed, the rate to be used for the next period

shall be adjusted to agree with the actual rate found.

7.5 MAWP Determination

The MAWP for the continued use of piping systems shall be established using the applicable code. Computations

may be made for known materials if all the following essential details are known to comply with the principles of the

applicable code:

a) upper and/or lower temperature limits for specific materials,

b) quality of materials and workmanship,

c) inspection requirements,

d) reinforcement of openings,

e) any cyclical service requirements.

Copyright American Petroleum Institute

Provided by IHS under license with API

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LAMPIRAN D

ASME B31.3

(16)

ASME B31.3-2016

the wall thickness shall be increased to prevent over-stress, damage, collapse, or buckling due to superim-posed loads from supports, ice formation, backfill,transportation, handling, or other loads enumerated inpara. 301.

(b) Where increasing the thickness would excessivelyincrease local stresses or the risk of brittle fracture, oris otherwise impracticable, the impact of applied loadsmay be mitigated through additional supports, braces,or other means without requiring an increased wallthickness. Particular consideration should be given tothe mechanical strength of small pipe connections topiping or equipment.

PART 2PRESSURE DESIGN OF PIPING COMPONENTS

303 GENERAL

Components manufactured in accordance with stan-dards listed in Table 326.1 shall be considered suitablefor use at pressure–temperature ratings in accordancewith para. 302.2.1 or para. 302.2.2, as applicable. Therules in para. 304 are intended for pressure design ofcomponents not covered in Table 326.1, but may be usedfor a special or more-rigorous design of such compo-nents, or to satisfy requirements of para. 302.2.2. Designsshall be checked for adequacy of mechanical strengthas described in para. 302.5.

304 PRESSURE DESIGN OF COMPONENTS

304.1 Straight Pipe

304.1.1 General(a) The required thickness of straight sections of pipe

shall be determined in accordance with eq. (2)

tm p t + c (2)

The minimum thickness, T, for the pipe selected, con-sidering manufacturer’s minus tolerance, shall be notless than tm.

(b) The following nomenclature is used in the equa-tions for pressure design of straight pipe:

c p sum of the mechanical allowances (thread orgroove depth) plus corrosion and erosionallowances. For threaded components, thenominal thread depth (dimension h ofASME B1.20.1, or equivalent) shall apply. Formachined surfaces or grooves where the toler-ance is not specified, the tolerance shall beassumed to be 0.5 mm (0.02 in.) in addition tothe specified depth of the cut.

D p outside diameter of pipe as listed in tables ofstandards or specifications or as measured

d p inside diameter of pipe. For pressure designcalculation, the inside diameter of the pipe is

the maximum value allowable under the pur-chase specification.

E p quality factor from Table A-1A or Table A-1BP p internal design gage pressureS p stress value for material from Table A-1 or

Table A-1MT p pipe wall thickness (measured or minimum in

accordance with the purchase specification)t p pressure design thickness, as calculated in

accordance with para. 304.1.2 for internal pres-sure or as determined in accordance withpara. 304.1.3 for external pressure

tm p minimum required thickness, includingmechanical, corrosion, and erosion allowances

W p weld joint strength reduction factor in accor-dance with para. 302.3.5(e)

Y p coefficient from Table 304.1.1, valid for t < D/6and for materials shown. The value of Y maybe interpolated for intermediate temperatures.For t ≥ D/6,

Y pd + 2c

D + d + 2c

304.1.2 Straight Pipe Under Internal Pressure(a) For t < D/6, the internal pressure design thickness

for straight pipe shall be not less than that calculatedin accordance with either eq. (3a) or eq. (3b)

t pPD

2�SEW + PY� (3a)

t pP�d + 2c�

2�SEW − P�1 − Y�� (3b)

(b) For t ≥ D/6 or for P/SE > 0.385, calculation ofpressure design thickness for straight pipe requires spe-cial consideration of factors such as theory of failure,effects of fatigue, and thermal stress.

304.1.3 Straight Pipe Under External Pressure. Todetermine wall thickness and stiffening requirementsfor straight pipe under external pressure, the procedureoutlined in the BPV Code, Section VIII, Division 1, UG-28through UG-30 shall be followed, using as the designlength, L, the running centerline length between anytwo sections stiffened in accordance with UG-29. As anexception, for pipe with Do/t < 10, the value of S to beused in determining Pa2 shall be the lesser of the follow-ing values for pipe material at design temperature:

(a) 1.5 times the stress value from Table A-1 orTable A-1M of this Code, or

(b) 0.9 times the yield strength tabulated in Section II,Part D, Table Y-1 for materials listed therein

(The symbol Do in Section VIII is equivalent to D in thisCode.)

(16)

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Table 304.1.1 Values of Coefficient Y for t < D/6

Temperature, °C (°F)

482 (900) 510 538 566 593 621 649 677 (1,250)Material and Below (950) (1,000) (1,050) (1,100) (1,150) (1,200) and Above

Ferritic steels 0.4 0.5 0.7 0.7 0.7 0.7 0.7 0.7

Austenitic steels 0.4 0.4 0.4 0.4 0.5 0.7 0.7 0.7

Nickel alloys 0.4 0.4 0.4 0.4 0.4 0.4 0.5 0.7UNS Nos. N06617,N08800, N08810,and N08825

Gray iron 0.0 . . . . . . . . . . . . . . . . . . . . .

Other ductile metals 0.4 0.4 0.4 0.4 0.4 0.4 0.4 0.4

Fig. 304.2.1 Nomenclature for Pipe Bends

Extrados

R1Intrados

304.2 Curved and Mitered Segments of Pipe

304.2.1 Pipe Bends. The minimum required thick-ness, tm, of a bend, after bending, in its finished form,shall be determined in accordance with eqs. (2) and (3c)

t pPD

2[(SEW/I) + PY](3c)

where at the intrados (inside bend radius)

I p4(R1/D) − 14(R1/D) − 2

(3d)

and at the extrados (outside bend radius)

I p4(R1/D) + 14(R1/D) + 2

(3e)

and at the sidewall on the bend centerline radius,I p 1.0, and where

R1 p bend radius of welding elbow or pipe bend

Thickness variations from the intrados to the extradosand along the length of the bend shall be gradual. Thethickness requirements apply at the mid-span of thebend, �/2, at the intrados, extrados, and bend centerlineradius. The minimum thickness at the end tangents shallnot be less than the requirements of para. 304.1 forstraight pipe (see Fig. 304.2.1).

Fig. 304.2.3 Nomenclature for Miter Bends

304.2.2 Elbows. Manufactured elbows not in accor-dance with para. 303 shall be qualified as required bypara. 304.7.2 or designed in accordance withpara. 304.2.1, except as provided in para. 328.4.2(b)(6).

304.2.3 Miter Bends. An angular offset of 3 deg orless (angle � in Fig. 304.2.3) does not require designconsideration as a miter bend. Acceptable methods forpressure design of multiple and single miter bends aregiven in (a) and (b) below.

(a) Multiple Miter Bends. The maximum allowableinternal pressure shall be the lesser value calculated fromeqs. (4a) and (4b). These equations are not applicablewhen � exceeds 22.5 deg.

Pm pSEW�T − c�

r2 � T − c

�T − c� + 0.643 tan��r2�T − c� (4a)

Pm pSEW�T − c�

r2 � R1 − r2

R1 − 0.5r2 (4b)

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Table 302.3.5 Weld Joint Strength Reduction Factor, W

Component Temperature, Ti, °C (°F)

427 454 482 510 538 566 593 621 649 677 704 732 760 788 816Steel Group (800) (850) (900) (950) (1,000) (1,050) (1,100) (1,150) (1,200) (1,250) (1,300) (1,350) (1,400) (1,450) (1,500)

CrMo 1 0.95 0.91 0.86 0.82 0.77 0.73 0.68 0.64 . . . . . . . . . . . . . . . . . .[Notes (1)–(3)]

CSEF (N + T) . . . . . . . . . 1 0.95 0.91 0.86 0.82 0.77 . . . . . . . . . . . . . . . . . .[Notes (3)–(5)]

CSEF . . . . . . 1 0.5 0.5 0.5 0.5 0.5 0.5 . . . . . . . . . . . . . . . . . .[Notes (3) and (4)](Subcritical PWHT)

Autogenous welds in aus- . . . . . . . . . 1 1 1 1 1 1 1 1 1 1 1 1tenitic stainless grade3xx, and N088xx andN066xx nickel alloys[Note (6)]

Austenitic stainless grade . . . . . . . . . 1 0.95 0.91 0.86 0.82 0.77 0.73 0.68 0.64 0.59 0.55 0.53xx and N088xx nickelalloys [Notes (7) and(8)]

Other materials [Note (9)] . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

GENERAL NOTES:(a) Weld joint strength reduction factors at temperatures above the upper temperature limit listed in Appendix A for the base metal or out-

side of the applicable range in Table 302.3.5 are the responsibility of the designer. At temperatures below those where weld jointstrength reduction factors are tabulated, a value of 1.0 shall be used for the factor W where required; however, the additional rules ofthis Table and Notes do not apply.

(b) Tcr p temperature 25°C (50°F) below the temperature identifying the start of time-dependent properties listed under"NOTES – TIME-DEPENDENT PROPERTIES" (Txx) in the Notes to Tables 1A and 1B of the BPV Code Section II, Part D for the base metalsjoined by welding. For materials not listed in the BPV Code Section II, Part D, Tcr shall be the temperature where the creep rate orstress rupture criteria in paras. 302.3.2(d)(4), (5), and (6) governs the basic allowable stress value of the metals joined by welding.When the base metals differ, the lower value of Tcr shall be used for the weld joint.

(c) Ti p temperature, °C (°F), of the component for the coincident operating pressure–temperature condition, i, under consideration.(d) CAUTIONARY NOTE: There are many factors that may affect the life of a welded joint at elevated temperature and all of those factors

cannot be addressed in a table of weld strength reduction factors. For example, fabrication issues such as the deviation from a true cir-cular form in pipe (e.g., "peaking" at longitudinal weld seams) or offset at the weld joint can cause an increase in stress that mayresult in reduced service life and control of these deviations is recommended.

(e) The weld joint strength reduction factor, W, may be determined using linear interpolation for intermediate temperature values.

NOTES:(1) The Cr–Mo Steels include: 1⁄2Cr–1⁄2Mo, 1Cr–1⁄2Mo, 11⁄4Cr–1⁄2Mo–Si, 21⁄4Cr–1Mo, 3Cr–1Mo, 5Cr–1⁄2Mo, 9Cr–1Mo. Longitudinal and spiral

(helical seam) welds shall be normalized, normalized and tempered, or subjected to proper subcritical postweld heat treatment (PWHT)for the alloy. Required examination is in accordance with para. 341.4.4 or 305.2.4.

(2) Longitudinal and spiral (helical seam) seam fusion welded construction is not permitted for C–1⁄2Mo steel above 850°F.(3) The required carbon content of the weld filler metal shall be ≥0.05 C wt. %. See para. 341.4.4(b) for examination requirements.

Basicity index of SAW flux ≥1.0.(4) The CSEF (Creep Strength Enhanced Ferritic) steels include grades 91, 92, 911, 122, and 23.(5) N + T p Normalizing + Tempering PWHT.(6) Autogenous welds without filler metal in austenitic stainless steel (grade 3xx) and austenitic nickel alloys UNS Nos. N066xx and

N088xx. A solution anneal after welding is required for use of the factors in the Table. See para. 341.4.3(b) for examinationrequirements.

(7) Alternatively, the 100,000 hr Stress Rupture Factors listed in ASME Section III, Division 1, Subsection NH, Tables I-14.10 A-xx, B-xx,and C-xx may be used as the weld joint strength reduction factor for the materials and welding consumables specified.

(8) Certain heats of the austenitic stainless steels, particularly for those grades whose creep strength is enhanced by the precipitation oftemper-resistant carbides and carbonitrides, can suffer from an embrittlement condition in the weld heat affected zone that can lead topremature failure of welded components operating at elevated temperatures. A solution annealing heat treatment of the weld area miti-gates this susceptibility.

(9) For carbon steel, W p 1.0 for all temperatures. For materials other than carbon steel, CrMo, CSEF, and the austenitic alloys listed inTable 302.3.5, W shall be as follows: For Ti ≤ Tcr, W p 1.0. For Tcr < Ti ≤ 1,500°F, W p 1 − 0.000909(Ti − Tcr). If Ti exceeds the uppertemperature for which an allowable stress value is listed in Appendix A for the base metal, the value for W is the responsibility of thedesigner.

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(16) Table A-1 Basic Allowable Stresses in Tension for Metals (Cont’d)Numbers in Parentheses Refer to Notes for Appendix A Tables; Specifications Are ASTM Unless Otherwise Indicated

SpecifiedMin.Class/ Min. Min.

Strength, ksiType/ UNS Condition/ Temp., Temp.Material Spec. No. Grade No. Temper Size, in. P-No. (5) Notes °F (6) Tensile Yield to 100 200 300

Carbon Steel (Cont’d)Plates, Bars, Shapes, and Sheets (Structural)

. . . A283 A K01400 . . . . . . 1 (8c)(57) A 45 24 15.0 14.7 14.2

. . . A1011 30 K02502 . . . . . . 1 (8c)(57) A 49 30 16.3 16.3 16.3

. . . A283 B K01702 . . . . . . 1 (8c)(57) A 50 27 16.7 16.5 15.9

. . . A1011 33 K02502 . . . . . . 1 (8c)(57) A 52 33 17.3 17.3 17.3

. . . A1011 36 K02502 . . . . . . 1 (8c)(57) A 53 36 17.7 17.7 17.7

. . . A283 C K02401 . . . . . . 1 (8c)(57) A 55 30 18.3 18.3 17.7

. . . A1011 40 K02502 . . . . . . 1 (8c)(57) A 55 40 18.3 18.3 18.3

. . . A36 . . . K02600 . . . . . . 1 (8c) A 58 36 19.3 19.3 19.3

. . . A283 D K02702 . . . . . . 1 (8c)(57) A 60 33 20.0 20.0 19.5

. . . A1011 45 K02507 . . . . . . 1 (8c)(57) A 60 45 20.0 20.0 20.0

. . . A1011 50 K02507 . . . . . . 1 (8c)(57) A 65 50 21.7 21.7 21.7

. . . A992 . . . . . . . . . . . . 1 (8c)(57) A 65 50 19.9 19.9 19.9

Forgings and Fittings

. . . A350 LF1 K03009 . . . . . . 1 (9)(57)(59) −20 60 30 20.0 18.3 17.7

. . . A181 . . . K03502 60 . . . 1 (9)(57)(59) A 60 30 20.0 18.3 17.7

. . . A420 WPL6 K03006 . . . . . . 1 (57) −50 60 35 20.0 20.0 20.0

. . . A234 WPB K03006 . . . . . . 1 (57)(59) B 60 35 20.0 20.0 20.0

. . . A350 LF2 K03011 1 . . . 1 (9)(57) −50 70 36 23.3 22.0 21.2

. . . A350 LF2 K03011 2 . . . 1 (9)(57) 0 70 36 23.3 22.0 21.2

. . . A105 . . . K03504 . . . . . . 1 (9)(57)(59) −20 70 36 23.3 22.0 21.2

. . . A181 . . . K03502 70 . . . 1 (9)(57)(59) A 70 36 23.3 22.0 21.2

. . . A234 WPC K03501 . . . . . . 1 (57)(59) B 70 40 23.3 23.3 23.3

Castings (2)

. . . A216 WCA J02502 . . . . . . 1 (57) −20 60 30 20.0 18.3 17.7

. . . A352 LCB J03003 . . . . . . 1 (9)(57) −50 65 35 21.7 21.4 20.6

. . . A352 LCC J02505 . . . . . . 1 (9) −50 70 40 23.3 23.3 23.3

. . . A216 WCB J03002 . . . . . . 1 (9)(57) −20 70 36 23.3 22.0 21.2

. . . A216 WCC J02503 . . . . . . 1 (9)(57) −20 70 40 23.3 23.3 23.3

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Table A-1B Basic Quality Factors for Longitudinal Weld Joints in Pipes and Tubes, EjThese quality factors are determined in accordance with para. 302.3.4(a). See also para. 302.3.4(b) and

Table 302.3.4 for increased quality factors applicable in special cases. Specifications, except API, are ASTM.

Ej Appendix ASpec. No. Class (or Type) Description [Note (2)] Notes

Carbon Steel

API 5L . . . Seamless pipe 1.00 . . .Electric fusion welded pipe, 100% radiographed 1.00 . . .Electric resistance welded pipe 0.85 . . .Electric fusion welded pipe, double butt seam 0.95 . . .Continuous welded (furnace butt welded) pipe 0.60 . . .

A53 Type S Seamless pipe 1.00 . . .Type E Electric resistance welded pipe 0.85 . . .Type F Furnace butt welded pipe 0.60 . . .

A105 . . . Forgings 1.00 (9)A106 . . . Seamless pipe 1.00 . . .A134 . . . Electric fusion welded pipe, single butt, straight 0.80 . . .

or spiral (helical) seamA135 . . . Electric resistance welded pipe 0.85 . . .A139 . . . Electric fusion welded pipe, straight or spiral 0.80 . . .

(helical) seamA179 . . . Seamless tube 1.00 . . .A181 . . . Forgings 1.00 (9)

A333 . . . Seamless pipe 1.00 . . .Electric resistance welded pipe 0.85 . . .

A334 . . . Seamless tube 1.00 . . .A350 . . . Forgings 1.00 (9)A369 . . . Seamless pipe 1.00 . . .A381 . . . Electric fusion welded pipe, 100% radiographed 1.00 . . .

Electric fusion welded pipe, spot radiographed 0.90 (19)Electric fusion welded pipe, as manufactured 0.85 . . .

A524 . . . Seamless pipe 1.00 . . .A587 . . . Electric resistance welded pipe 0.85 . . .

A671 12, 22, 32, 42, 52 Electric fusion welded pipe, 100% radiographed 1.00 . . .13, 23, 33, 43, 53 Electric fusion welded pipe, double butt seam 0.85 . . .



Low and Intermediate Alloy Steel

A182 . . . Forgings 1.00 (9)

A333 . . . Seamless pipe 1.00 . . .Electric resistance welded pipe 0.85 (78)

A334 . . . Seamless tube 1.00 . . .A335 . . . Seamless pipe 1.00 . . .A350 . . . Forgings 1.00 . . .A369 . . . Seamless pipe 1.00 . . .

A671 12, 22, 32, 42, 52 Electric fusion welded pipe, 100% radiographed 1.00 . . .13, 23, 33, 43, 53 Electric fusion welded pipe, double butt seam 0.85 (78)



(16)

[email protected]

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LAMPIRAN E

ASTM A105

LAMPIRAN F

HANDBOOK OF

CORROSION ENGINEERING

833

Corrosion Inhibitors

10.1 Introduction 833

10.2 Classification of Inhibitors 834

10.2.1 Passivating (anodic) 836

10.2.2 Cathodic 837

10.2.3 Organic 837

10.2.4 Precipitation inhibitors 837

10.2.5 Volatile corrosion inhibitors 838

10.3 Corrosion Inhibition Mechanism 838

10.3.1 Inhibitors for acid solutions 839

10.3.2 Inhibitors in near-neutral solutions 845

10.3.3 Inhibitors for oil and gas systems 851

10.3.4 Atmospheric and gaseous corrosion 857

10.4 Selection of an Inhibitor System 860

References 861

10.1 Introduction

The use of chemical inhibitors to decrease the rate of corrosionprocesses is quite varied. In the oil extraction and processing indus-tries, inhibitors have always been considered to be the first line ofdefense against corrosion. A great number of scientific studies havebeen devoted to the subject of corrosion inhibitors. However, most ofwhat is known has grown from trial and error experiments, both in thelaboratories and in the field. Rules, equations, and theories to guideinhibitor development or use are very limited.

By definition, a corrosion inhibitor is a chemical substance that, whenadded in small concentration to an environment, effectively decreasesthe corrosion rate. The efficiency of an inhibitor can be expressed by ameasure of this improvement:

Chapter

10

0765162_Ch10_Roberge 9/1/99 6:15 Page 833

Inhibitor efficiency (%) � 100 (10.1)

where CRuninhibited � corrosion rate of the uninhibited systemCRinhibited � corrosion rate of the inhibited system

In general, the efficiency of an inhibitor increases with an increasein inhibitor concentration (e.g., a typically good inhibitor would give95% inhibition at a concentration of 0.008% and 90% at a concentra-tion of 0.004%). A synergism, or cooperation, is often present betweendifferent inhibitors and the environment being controlled, and mix-tures are the usual choice in commercial formulations. The scientificand technical corrosion literature has descriptions and lists of numer-ous chemical compounds that exhibit inhibitive properties. Of these,only very few are actually used in practice. This is partly because thedesirable properties of an inhibitor usually extend beyond those sim-ply related to metal protection. Considerations of cost, toxicity, avail-ability, and environmental friendliness are of considerable importance.

Table 10.1 presents some inhibitors that have been used with suc-cess in typical corrosive environments to protect the metallic elementsof industrial systems. Commercial inhibitors are available under var-ious trade names and labels that usually provide little or no informa-tion about their chemical composition. It is sometimes very difficult todistinguish between products from different sources because they maycontain the same basic anticorrosion agent. Commercial formulationsgenerally consist of one or more inhibitor compounds with other addi-tives such as surfactants, film enhancers, de-emulsifiers, oxygen scav-engers, and so forth. The inhibitor solvent package used can be criticalin respect to the solubility/dispersibility characteristics and hence theapplication and performance of the products.

10.2 Classification of Inhibitors

Inhibitors are chemicals that react with a metallic surface, or the envi-ronment this surface is exposed to, giving the surface a certain level ofprotection. Inhibitors often work by adsorbing themselves on the metallicsurface, protecting the metallic surface by forming a film. Inhibitors arenormally distributed from a solution or dispersion. Some are included ina protective coating formulation. Inhibitors slow corrosion processes by

� Increasing the anodic or cathodic polarization behavior (Tafel slopes)� Reducing the movement or diffusion of ions to the metallic surface� Increasing the electrical resistance of the metallic surface

(CRuninhibited � CRinhibited) ��

CRuninhibited

834 Chapter Ten

0765162_Ch10_Roberge 9/1/99 6:15 Page 834

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Highlight

LAMPIRAN G

DATA IMMERSION TEST

LAMPIRAN H

MSDS NaNO2

p. 1p. 1

0033 11

He He aa lthlth

FireFire

R e R e a ca c t i v i t yt i v i t y

P e rP e rs s oo n an a llP r o t e P r o t e c t i oc t i o nn

33

00

00

CC

Material Safety Data SheetMaterial Safety Data SheetSodium nitrite MSDSSodium nitrite MSDS

Section 1: Chemical Product and Company IdentificationSection 1: Chemical Product and Company Identification

Product Name:Product Name: Sodium nitrite Sodium nitrite

Catalog Codes:Catalog Codes: SLS2356, SLS3778, SLS1558 SLS2356, SLS3778, SLS1558

CAS#:CAS#: 7632-00-0 7632-00-0

RTECS:RTECS: RA1225000 RA1225000

TSCA:TSCA: TSCA 8(b) inventory: Sodium nitrite TSCA 8(b) inventory: Sodium nitrite

CI#:CI#: Not available. Not available.

Synonym:Synonym:

Chemical Name:Chemical Name: Sodium Nitrite Sodium Nitrite

Chemical Formula:Chemical Formula: NaNO2 NaNO2

Contact Information:Contact Information:

Sciencelab.com, Inc.Sciencelab.com, Inc.14025 Smith Rd.14025 Smith Rd.Houston, Texas 77396Houston, Texas 77396

US Sales:US Sales: 1-800-901-72471-800-901-7247International Sales:International Sales: 1-281-441-44001-281-441-4400

Order Online:Order Online: ScienceLab.comScienceLab.com

CHEMTREC (24HR Emergency Telephone), call:CHEMTREC (24HR Emergency Telephone), call:1-800-424-93001-800-424-9300

International CHEMTREC, call:International CHEMTREC, call: 1-703-527-3887 1-703-527-3887

For non-emergency assistance, call:For non-emergency assistance, call: 1-281-441-4400 1-281-441-4400

Section 2: Composition and Information on IngredientsSection 2: Composition and Information on Ingredients

Composition:Composition:

NNaammee CCAAS S ## % % bby y WWeeiigghhtt

SSooddiiuum m nniittrriittee 77663322--0000--00 110000

Toxicological Data on Ingredients:Toxicological Data on Ingredients: Sodium nitrite: ORAL (LD50): Acute: Sodium nitrite: ORAL (LD50): Acute: 180 mg/kg [Rat]. 175 mg/kg [Mouse].180 mg/kg [Rat]. 175 mg/kg [Mouse].

Section 3: Hazards IdentificationSection 3: Hazards Identification

Potential Acute Health Effects:Potential Acute Health Effects:Very hazardous in case of Very hazardous in case of eye contact (irritant), of ingestion, of inhalation. Hazardous in eye contact (irritant), of ingestion, of inhalation. Hazardous in case of skin contact (irritant).case of skin contact (irritant).Slightly hazardous in case Slightly hazardous in case of skin contact (permeator). Prolonged exposure may result in skin of skin contact (permeator). Prolonged exposure may result in skin burns and ulcerations. Over-burns and ulcerations. Over-exposure by inhalation may cause exposure by inhalation may cause respiratory irritation. Severe over-exposure can result in death. Inflammation of the eye respiratory irritation. Severe over-exposure can result in death. Inflammation of the eye isischaracterized by redness, watering, and itching.characterized by redness, watering, and itching.

Potential Chronic Health Effects:Potential Chronic Health Effects:CARCINOGENIC EFFECTS: Not available. MUTAGENIC EFFECTS: Mutagenic for mammalian somatic cells. MutagenicCARCINOGENIC EFFECTS: Not available. MUTAGENIC EFFECTS: Mutagenic for mammalian somatic cells. Mutagenicfor bacteria and/or yeast. TERATOGENIC EFFECTS: Classified POSSIBLE for human. DEVELOPMENTAL TOXICITY:for bacteria and/or yeast. TERATOGENIC EFFECTS: Classified POSSIBLE for human. DEVELOPMENTAL TOXICITY:Classified Reproductive system/toxin/female, Reproductive system/toxin/male [POSSIBLE]. The substance may be toxic toClassified Reproductive system/toxin/female, Reproductive system/toxin/male [POSSIBLE]. The substance may be toxic toblood, cardiovascular system, Smooth Muscle. Repeated or prolonged exposure blood, cardiovascular system, Smooth Muscle. Repeated or prolonged exposure to the substance can produce target organsto the substance can produce target organsdamage. Repeated exposure to a highly toxic material may produce general deterioration of health by an accumulation in onedamage. Repeated exposure to a highly toxic material may produce general deterioration of health by an accumulation in oneor many human organs.or many human organs.

Section 4: First Aid MeasuresSection 4: First Aid Measures

p. 2

Eye Contact:Check for and remove any contact lenses. In case of contact, immediately flush eyes with plenty of water for at least 15minutes. Cold water may be used. Get medical attention immediately.

Skin Contact:In case of contact, immediately flush skin with plenty of water. Cover the irritated skin with an emollient. Remove contaminatedclothing and shoes. Cold water may be used.Wash clothing before reuse. Thoroughly clean shoes before reuse. Get medicalattention.

Serious Skin Contact:Wash with a disinfectant soap and cover the contaminated skin with an anti-bacterial cream. Seek immediate medicalattention.

Inhalation:If inhaled, remove to fresh air. If not breathing, give artificial respiration. If breathing is difficult, give oxygen. Get medicalattention immediately.

Serious Inhalation:Evacuate the victim to a safe area as soon as possible. Loosen tight clothing such as a collar, tie, belt or waistband. Ifbreathing is difficult, administer oxygen. If the victim is not breathing, perform mouth-to-mouth resuscitation. WARNING: It maybe hazardous to the person providing aid to give mouth-to-mouth resuscitation when the inhaled material is toxic, infectious orcorrosive. Seek immediate medical attention.

Ingestion:If swallowed, do not induce vomiting unless directed to do so by medical personnel. Never give anything by mouth to anunconscious person. Loosen tight clothing such as a collar, tie, belt or waistband. Get medical attention immediately.

Serious Ingestion: Not available.

Section 5: Fire and Explosion Data

Flammability of the Product: Non-flammable.

Auto-Ignition Temperature: Not applicable.

Flash Points: Not applicable.

Flammable Limits: Not applicable.

Products of Combustion: Not available.

Fire Hazards in Presence of Various Substances: Not applicable.

Explosion Hazards in Presence of Various Substances:Risks of explosion of the product in presence of static discharge: Not available. Slightly explosive in presence of shocks, ofheat.

Fire Fighting Media and Instructions: Not applicable.

Special Remarks on Fire Hazards:When in contact with organic matter, it will ignite by friction. May ignite combustibles.

Special Remarks on Explosion Hazards:Explodes when heated over 1000 F (538 C). Sodium Nitrite + thiocyanate explodes on heating. A mixture of sodium nitrite andvarious cyanides explodes on contact. Mixture of sodium nitrite and phthalic acid or anhydride explode violently on heating.Fusion of urea with sodium nitrite Interaction of nitrites when heated with metal amidosulfates (sulfamates) may becomeexplosively violent owing to liberation of nitrogen and steam mixed with ammonium sulfamate form. Violent explosion occursif an ammonium salt is is melted with nitrite salt. Shock may explode nitrites. must be carried out exactly as described to avoidirsk of explosion.

Section 6: Accidental Release Measures

p. 3

Small Spill: Use appropriate tools to put the spilled solid in a convenient waste disposal container.

Large Spill:Oxidizing material. Poisonous solid. Stop leak if without risk. Do not get water inside container. Avoid contact with acombustible material (wood, paper, oil, clothing...). Keep substance damp using water spray. Do not touch spi lled material.Use water spray to reduce vapors. Prevent entry into sewers, basements or confined areas; dike if needed. Call for assistanceon disposal.

Section 7: Handling and Storage

Precautions:Keep locked up.. Keep away from heat. Keep away from sources of ignition. Keep away from combustible material.. Do notingest. Do not breathe dust. In case of insufficient ventilation, wear suitable respiratory equipment. If ingested, seek medicaladvice immediately and show the container or the label. Avoid contact with skin and eyes. Keep away from incompatibles suchas reducing agents, combustible materials, organic materials, metals, acids.

Storage:Oxidizer. Hygroscopic. Air sensitive. Keep container tightly closed. Keep container in a cool, well-ventilated area. Separatefrom acids, alkalies, reducing agents and combustibles. See NFPA 43A, Code for the Storage of Liquid and Solid Oxidizers.Do not store above 23°C (73.4°F).

Section 8: Exposure Controls/Personal Protection

Engineering Controls:Use process enclosures, local exhaust ventilation, or other engineering controls to keep airborne levels below recommendedexposure limits. If user operations generate dust, fume or mist, use ventilation to keep exposure to airborne contaminantsbelow the exposure limit.

Personal Protection: Safety glasses. Synthetic apron. Gloves (impervious).

Personal Protection in Case of a Large Spill:Splash goggles. Full suit. Boots. Gloves. Suggested protective clothing might not be sufficient; consult a specialist BEFOREhandling this product.

Exposure Limits: Not available.

Section 9: Physical and Chemical Properties

Physical state and appearance: Solid. (Powdered solid.)

Odor: Odorless.

Taste: Saline. (Slight.)

Molecular Weight: 69 g/mole

Color: White to slightly yellowish.

pH (1% soln/water): 9 [Basic.]

Boiling Point: 320°C (608°F)

Melting Point: 271°C (519.8°F)

Critical Temperature: Not available.

Specific Gravity: 2.2 (Water = 1)

Vapor Pressure: Not applicable.

Vapor Density: Not available.

p. 4

Volatility: Not available.

Odor Threshold: Not available.

Water/Oil Dist. Coeff.: Not available.

Ionicity (in Water): Not available.

Dispersion Properties: See solubility in water, methanol.

Solubility:Easily soluble in hot water. Soluble in cold water. Partially soluble in methanol. Very slightly soluble in diethyl ether.

Section 10: Stability and Reactivity Data

Stability: The product is stable.

Instability Temperature: Not available.

Conditions of Instability:Excess heat, dust generation, ignition sources, exposure to air, combustible materials, incompatible materials, exposure tomoist air or water.

Incompatibility with various substances:Highly reactive with combustible materials, organic materials. Reactive with reducing agents, metals, acids. Slightly reactive toreactive with moisture.

Corrosivity: Non-corrosive in presence of glass.

Special Remarks on Reactivity:Hygroscopic. Strong oxidizer. Slowly oxidizes to nitrate in air. Reacts vigorously with reducing materials. Sodium nitrite isa strong oxidizer and is incompatible with the following: acetanilide, metals as powders, ammonium salts, aminoguanidinesalts, anitpyrine, Butadiene, chlorates, hypophosphites, activated carbon, iodides, mercury salts, permanganate, phthalic acid,phthalic anydride, sodium amide, sodium disulphi te, cyanides (e.g. potassium cyanide, sodium cyanide), sodium thiocyanate,lithium, sulfites, tannic acid, urea, wood, vegetable astringent decoctions, infusions, or tinctures.

Special Remarks on Corrosivity: Not available.

Polymerization: Will not occur.

Section 11: Toxicological Information

Routes of Entry: Absorbed through skin. Inhalation. Ingestion.

Toxicity to Animals:WARNING: THE LC50 VALUES HEREUNDER ARE ESTIMATED ON THE BASIS OF A 4-HOUR EXPOSURE. Acute oraltoxicity (LD50): 175 mg/kg [Mouse]. Acute toxicity of the dust (LC50): 5.5 4 hours [Rat].

Chronic Effects on Humans:MUTAGENIC EFFECTS: Mutagenic for mammalian somatic cells. Mutagenic for bacteria and/or yeast. TERATOGENICEFFECTS: Classified POSSIBLE for human. DEVELOPMENTAL TOXICITY: Classified Reproductive system/toxin/female,Reproductive system/toxin/male [POSSIBLE]. May cause damage to the following organs: blood, cardiovascular system,Smooth Muscle.

Other Toxic Effects on Humans:Very hazardous in case of ingestion, of inhalation. Hazardous in case of skin contact (irritant). Slightly hazardous in case ofskin contact (permeator).

Special Remarks on Toxicity to Animals: Not available.

Special Remarks on Chronic Effects on Humans:May cause cancer (tumorigen), affect gentic material (mutagen), cause adverse reproductive effects (fertility, fetotoxicity) andbirth defects based on animal data. Passes through the placental barrier in animal.

p. 5

Special Remarks on other Toxic Effects on Humans:Acute Potential Health Effects: Skin: Causes skin irritation. May be absorbed through skin. Eyes: Causes eye irritation. Maycause conjunctivitis. May cause permanent corneal opacification. Ingestion: Harmful if swallowed. Causes gastrointestinaltract irritation with nausea. May affect behavior, brain, nervous system (change in motor activity, muscular incoordination,loss of reflexes, convulsions, coma), blood (methemoglobinemia), liver, metabolism, cardiovasular system (decrease inblood pressure, rapid pulse) and urinary system. May also cause weakness. Inhalation: May be fatal if inhaled. May causerespiratory tract irritation, cyanosis, dyspena, pulmonary edema, asphyxia, chemical pneumonitis, upper airway obstructioncaused by edema and possible death. May cause biochemical changes. May affect the blood (methemoglobinemia), and thecardiovascular system (tachycardia).

Section 12: Ecological Information

Ecotoxicity: Not available.

BOD5 and COD: Not available.

Products of Biodegradation:Possibly hazardous short term degradation products are not l ikely. However, long term degradation products may arise.

Toxicity of the Products of Biodegradation: The products of degradation are less toxic than the product itself.

Special Remarks on the Products of Biodegradation: Not available.

Section 13: Disposal Considerations

Waste Disposal:Waste must be disposed of in accordance with federal, state and local environmental control regulations.

Section 14: Transport Information

DOT Classification:CLASS 5.1: Oxidizing material. CLASS 6.1: Poisonous material.

Identification: : Sodium nitrite UNNA: 1500 PG: III

Special Provisions for Transport: Marine Pollutant

Section 15: Other Regulatory Information

Federal and State Regulations:New York release reporting list: Sodium nitrite Pennsylvania RTK: Sodium nitrite Massachusetts RTK: Sodium nitrite NewJersey: Sodium nitrite California Director's List of Hazardous Substances: Sodium nitrite TSCA 8(b) inventory: Sodiumnitrite TSCA 12(b) one time export: Sodium nitrite SARA 313 toxic chemical notification and release reporting: Sodium nitriteCERCLA: Hazardous substances.: Sodium nitrite: 100 lbs. (45.36 kg)

Other Regulations:OSHA: Hazardous by definition of Hazard Communication Standard (29 CFR 1910.1200). EINECS: This product is on theEuropean Inventory of Existing Commercial Chemical Substances.

Other Classifications:

WHMIS (Canada):CLASS C: Oxidizing material. CLASS D-1A: Material causing immediate and serious toxic effects (VERY TOXIC). CLASSD-2A: Material causing other toxic effects (VERY TOXIC).

DSCL (EEC):

HMIS (U.S.A.):

p. 6

Health Hazard: 3

Fire Hazard: 0

Reactivity: 0

Personal Protection: C

National Fire Protection Association (U.S.A.):

Health: 3

Flammability: 0

Reactivity: 1

Specific hazard:

Protective Equipment:Gloves (impervious). Synthetic apron. Wear appropriate respirator when ventilation is inadequate. Safety glasses.

Section 16: Other Information

References: Not available.

Other Special Considerations: Not available.

Created: 10/10/2005 08:27 PM

Last Updated: 05/21/2013 12:00 PM

The information above is believed to be accurate and represents the best information currently available to us. However, we make no warranty of merchantability or any other warranty, express or implied, with respect to such information, and we assume no liability resulting from its use. Users should make their own investigations to determine the suitability of the information for their particular purposes. In no event shall ScienceLab.com be liable for any claims, losses, or damages of any third party or for lost profits or any special, indirect, incidental, consequential or exemplary damages, howsoever arising, even if ScienceLab.com has been advised of the possibility of such damages.

LAMPIRAN I

MSDS Na2CrO4

p. 1p. 1

0033 00

He He aa lthlth

FireFire

R e R e a ca c t i v i t yt i v i t y

P e rP e rs s oo n an a llP r o t e P r o t e c t i oc t i o nn

33

00

00

EE

Material Safety Data SheetMaterial Safety Data SheetSodium chromate anhydrous MSDSSodium chromate anhydrous MSDS


Product Name:Product Name: Sodium chromate anhydrous Sodium chromate anhydrous

Catalog Codes:Catalog Codes: SLS3043 SLS3043

CAS#:CAS#: 7775-11-3 7775-11-3

RTECS:RTECS: GB2955000 GB2955000

TSCA:TSCA: TSCA 8(b) inventory: Sodium chromate anhydrous TSCA 8(b) inventory: Sodium chromate anhydrous

CI#:CI#: Not available. Not available.

Synonym:Synonym: Disodium Disodium ChromateChromate

Chemical Name:Chemical Name: Chromic Acid, disodium salt Chromic Acid, disodium salt

Chemical Formula:Chemical Formula: Na2CrO4 Na2CrO4











SSooddiiuum m cchhrroommaatte e tteettrraahhyyddrraattee 1100003344--8822--99 110000

Toxicological Data on Ingredients:Toxicological Data on Ingredients: Sodium chromate tetrahydrate: DERMAL (LD50): Acute: 101 mg/kg [Rabbit]. Sodium chromate tetrahydrate: DERMAL (LD50): Acute: 101 mg/kg [Rabbit].


Potential Acute Health Effects:Potential Acute Health Effects:Very hazardous in case of Very hazardous in case of skin contact (irritant, permeator), of eye contact (irritant), of ingestion, . Hazardous in case skin contact (irritant, permeator), of eye contact (irritant), of ingestion, . Hazardous in case of skinof skincontact (corrosive, sensitizer), of eye contact (corrosive), of inhalation (lung irritant). Severe over-exposure can contact (corrosive, sensitizer), of eye contact (corrosive), of inhalation (lung irritant). Severe over-exposure can result in death.result in death.Inflammation of the eye is characterized by redness, wInflammation of the eye is characterized by redness, watering, and itching. Skin inflammation is atering, and itching. Skin inflammation is characterized by itching,characterized by itching,scaling, reddening, or, occasionally, blistering.scaling, reddening, or, occasionally, blistering.

Potential Chronic Health Effects:Potential Chronic Health Effects:CARCINOGENIC EFFECTS: Classified A1 (Confirmed for human.) by ACGIH, 1 (Proven for human.) by IARC. MUTAGENICCARCINOGENIC EFFECTS: Classified A1 (Confirmed for human.) by ACGIH, 1 (Proven for human.) by IARC. MUTAGENICEFFECTS: Mutagenic for mammalian somatic cells. Mutagenic for EFFECTS: Mutagenic for mammalian somatic cells. Mutagenic for bacteria and/or yeast. TERATOGENIC EFFECTS: Notbacteria and/or yeast. TERATOGENIC EFFECTS: Notavailable. DEVELOPMENTAL TOXICITY: Not available. The substance may be toxic to blood, kidneys, liver, upper respiratoryavailable. DEVELOPMENTAL TOXICITY: Not available. The substance may be toxic to blood, kidneys, liver, upper respiratorytract. Repeated or prolonged exposure to the substance can tract. Repeated or prolonged exposure to the substance can produce target organs damage. Repeated exposure to a hiproduce target organs damage. Repeated exposure to a highlyghlytoxic material may produce general deterioration of healtoxic material may produce general deterioration of health by an accumulation in th by an accumulation in one or many human organs.one or many human organs.


p. 2

Eye Contact:Check for and remove any contact lenses. In case of contact, immediately flush eyes with plenty of water for at least 15minutes. Cold water may be used. Get medical attention immediately.

Skin Contact:In case of contact, immediately flush skin with plenty of water for at least 15 minutes while removing contaminated clothingand shoes. Cover the irritated skin with an emollient. Cold water may be used.Wash clothing before reuse. Thoroughly cleanshoes before reuse. Get medical attention immediately.

Serious Skin Contact:Wash with a disinfectant soap and cover the contaminated skin with an anti-bacterial cream. Seek immediate medicalattention.

Inhalation:If inhaled, remove to fresh air. If not breathing, give artificial respiration. If breathing is difficult, give oxygen. Get medicalattention immediately.

Serious Inhalation:Evacuate the victim to a safe area as soon as possible. Loosen tight clothing such as a collar, tie, belt or waistband. Ifbreathing is difficult, administer oxygen. If the victim is not breathing, perform mouth-to-mouth resuscitation. WARNING: It maybe hazardous to the person providing aid to give mouth-to-mouth resuscitation when the inhaled material is toxic, infectious orcorrosive. Seek immediate medical attention.

Ingestion:If swallowed, do not induce vomiting unless directed to do so by medical personnel. Never give anything by mouth to anunconscious person. Loosen tight clothing such as a collar, tie, belt or waistband. Get medical attention immediately.








Fire Hazards in Presence of Various Substances: combustible materials, organic materia

Explosion Hazards in Presence of Various Substances:Risks of explosion of the product in presence of mechanical impact: Not available. Risks of explosion of the product inpresence of static discharge: Not available.


Special Remarks on Fire Hazards:Toxic chromium oxide fumes may form in fire. May increase intensity of fire when in contact with combustible material. Contactwith combustible or organic materials may cause fire. When heated to decomposition it emits toxic fumes of sodium oxide

Special Remarks on Explosion Hazards: Hydrazine is decomposed explosively by chromates


Small Spill: Use appropriate tools to put the spilled solid in a convenient waste disposal container.

Large Spill:Poisonous solid. Stop leak if without risk. Do not get water inside container. Do not touch spilled material. Use water spray toreduce vapors. Prevent entry into sewers, basements or confined areas; dike if needed. Call for assistance on disposal. Becareful that the product is not present at a concentration level above TLV. Check TLV on the MSDS and with local authorities.

p. 3


Precautions:Keep container dry. Do not ingest. Do not breathe dust. Never add water to this product. In case of insufficient ventilation,wear suitable respiratory equipment. If ingested, seek medical advice immediately and show the container or the label. Avoidcontact with skin and eyes. Keep away from incompatibles such as combustible materials, organic materials.

Storage: Keep container tightly closed. Keep container in a cool, well-ventilated area.



Personal Protection:Splash goggles. Lab coat. Dust respirator. Be sure to use an approved/certified respirator or equivalent. Gloves.

Personal Protection in Case of a Large Spill:Splash goggles. Full suit. Dust respirator. Boots. Gloves. A self contained breathing apparatus should be used to avoidinhalation of the product. Suggested protective clothing might not be sufficient; consult a specialist BEFORE handling thisproduct.

Exposure Limits:TWA: 0.05 (mg (Cr)/m) from ACGIH (TLV) [United States] Consult local authorities for acceptable exposure limits.


Physical state and appearance:Solid. (Crystals solid. Somewhat deliquescent crystals solid.)

Odor: Odorless.

Taste: Not available.

Molecular Weight: 161.97 g/mole

Color: Yellow.

pH (1% soln/water): Not available.

Boiling Point: Not available.



Specific Gravity: Density: 2.723 (Water = 1)







Dispersion Properties: See solubility in water.

Solubility:

p. 4

Easily soluble in hot water. Soluble in cold water. Slightly soluble in ethyl alcohol, methyl alcohol. Solubility in water: 873 g/lwater @ 30 deg. C




Conditions of Instability: Store away from combustibles; avoid high temperatures; keep well closed.

Incompatibility with various substances: Reactive with combustible materials, organic materials.

Corrosivity: Non-corrosive in presence of glass.

Special Remarks on Reactivity: Any combustible, organic, or readily oxidizable material (paper, wood, sulfur, aluminum,plastics)




Routes of Entry: Absorbed through skin. Dermal contact. Eye contact. Inhalation. Ingestion.

Toxicity to Animals: Acute oral toxicity (LD50): 136 mg/kg [Rat].

Chronic Effects on Humans:CARCINOGENIC EFFECTS: Classified A1 (Confirmed for human.) by ACGIH, 1 (Proven for human.) by IARC. MUTAGENICEFFECTS: Mutagenic for mammalian somatic cells. Mutagenic for bacteria and/or yeast. May cause damage to the followingorgans: blood, kidneys, liver, upper respiratory tract.

Other Toxic Effects on Humans:Very hazardous in case of skin contact (irritant, permeator), of ingestion, . Hazardous in case of skin contact (corrosive,sensitizer), of eye contact (corrosive), of inhalation (lung i rritant).

Special Remarks on Toxicity to Animals: Not available.

Special Remarks on Chronic Effects on Humans:May affect genetic material (mutagenic). May cause adverse reproductive effects based on animal test data

Special Remarks on other Toxic Effects on Humans:Acute Potential Health Effects: Skin: Corrosive. It causes severe skin irritation with reddness and pain, and may causeburns. Contact with broken skin may cause ulcers (chromic sores) and absorption which may cause systemic poisoning. Itmay be fatal if absorbed through skin. May affect behavior/central nervous system/nervous system (somnolence, muscleweakness, flaccid paraylsis withough anesthesia), function) if absorbed through skin. May cause skin sensitization ordermatitis. Eyes: Corrosive. Contact can cause blurred vision, rednes, pain, severe irritation, conjunctivitis, and cornealtissue burns. It may cause corneal injury or blindness. Inhalation: Causes respiratory tract irritation. It is destructive to thetissues of the mucous membranes and upper respiratory tract. It may cause ulceration and perforation of the nasal septum.Symptoms may include sore throat, coughing, shortness of breath, and labored breathing. It may product pulmonary edema,sensitization or allergic asthma. Higher exposures may cause pulmonary edema. Ingestion: Corrosive. Harmful if swallowed.Ingestion can cause severe burns of the mough, throat, and stomach, leading to death. It can cause sore throat, intense thirst,muscle cramps, vomiting, nausea, diarrhea, violent gastroenteritis, violent epigastric pain, peripheral vascular collapse, liverdamage (elevated liver enzymes, acute hepatic failure), acute renal failure, renal tubular necrosis, mydriasis, and may affectbehavior (somnolence, dizziness, coma), respiration (respiratory distress syndrome), cardiovascular system (hypotension orhypertension, dysrythmia, circulatory collapse, shock), and blood. Chronic Potential Health Effects: Repeated or prolongedexposure can cause ulceration and perforation of the nasal septum, respiratory tract irritation, bronchitis, plumonary fibrosis,emphysema, asthma, liver and kidney damage, and ulceration of the skin. Ulcerations at first may be painless, but maypenetrate to the bone producing "chromic holes." respiration, liver function, urinary system (kidney

p. 5





Toxicity of the Products of Biodegradation: The products of degradation are less toxic than the product itself.





DOT Classification: CLASS 6.1: Poisonous material.

Identification: : Toxic solid, inorganic, n.o.s (sodium chromate) UNNA: 3288 PG: I

Special Provisions for Transport: Not available.


Federal and State Regulations:California prop. 65: This product contains the following ingredients for which the State of California has found to cause cancer,birth defects or other reproductive harm, which would require a warning under the statute: Sodium chromate anhydrousCalifornia prop. 65: This product contains the following ingredients for which the State of California has found to cause cancerwhich would require a warning under the statute: Sodium chromate anhydrous Connecticut hazardous material survey.:Sodium chromate anhydrous Illinois chemical safety act: Sodium chromate anhydrous New York release reporting l ist: Sodiumchromate anhydrous Pennsylvania RTK: Sodium chromate anhydrous Massachusetts RTK: Sodium chromate anhydrousMassachusetts spill list: Sodium chromate anhydrous New Jersey: Sodium chromate anhydrous New Jersey spill list: Sodiumchromate anhydrous Louisiana spill reporting: Sodium chromate anhydrous TSCA 8(b) inventory: Sodium chromate anhydrousTSCA 6 final risk management: Sodium chromate anhydrous TSCA 8(a) IUR: Sodium chromate anhydrous TSCA 12(b)annual export notification: Sodium chromate anhydrous SARA 313 toxic chemical notification and release reporting: Sodiumchromate anhydrous CERCLA: Hazardous substances.: Sodium chromate anhydrous: 10 lbs. (4.536 kg)

Other Regulations:


WHMIS (Canada):CLASS C: Oxidizing material. CLASS D-2A: Material causing other toxic effects (VERY TOXIC).

DSCL (EEC):R21- Harmful in contact with skin. R25- Toxic if swallowed. R26- Very toxic by inhalation. R37/38- Irritating to respiratorysystem and skin. R41- Risk of serious damage to eyes. R43- May cause sensitization by skin contact. R46- May causeheritable genetic damage. R49- May cause cancer by inhalation. R50/53- Very toxic to aquatic organisms, may causelong-term adverse effects in the aquatic environment. S45- In case of accident or if you feel unwell, seek medical adviceimmediately (show the label where possible). S53- Avoid exposure - obtain special instructions before use. S60- Thismaterial and its container must be disposed of as hazardous waste. S61- Avoid release to the environment. Refer to specialinstructions/Safety data sheets.

HMIS (U.S.A.):

p. 6

Health Hazard: 3

Fire Hazard: 0

Reactivity: 0

Personal Protection: E


Health: 3

Flammability: 0

Reactivity: 0

Specific hazard:

Protective Equipment:Gloves. Lab coat. Dust respirator. Be sure to use an approved/certified respirator or equivalent. Wear appropriate respiratorwhen ventilation is inadequate. Splash goggles.


References: Not available.


Created: 10/09/2005 06:31 PM

Last Updated: 05/21/2013 12:00 PM


LAMPIRAN J

MSDS NaCl

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Material Safety Data SheetMaterial Safety Data SheetSodium chloride MSDSSodium chloride MSDS


Product Name:Product Name: Sodium chloride Sodium chloride

Catalog Codes:Catalog Codes: SLS3262, SLS1045, SLS3889, SLS1669, SLS3262, SLS1045, SLS3889, SLS1669,SLS3091SLS3091

CAS#:CAS#: 7647-14-5 7647-14-5

RTECS:RTECS: VZ4725000 VZ4725000

TSCA:TSCA: TSCA 8(b) inventory: Sodium chloride TSCA 8(b) inventory: Sodium chloride

CI#:CI#: Not applicable. Not applicable.

Synonym:Synonym: Salt; Salt; Sea Sea SaltSalt

Chemical Name:Chemical Name: Sodium chloride Sodium chloride

Chemical Formula:Chemical Formula: NaCl NaCl











SSooddiiuum m cchhlloorriiddee 77664477--1144--55 110000

Toxicological Data on Ingredients:Toxicological Data on Ingredients: Sodium chloride: ORAL Sodium chloride: ORAL (LD50): Acute: 3000 mg/kg [Rat.]. 4000 mg/kg [Mouse].(LD50): Acute: 3000 mg/kg [Rat.]. 4000 mg/kg [Mouse].DERMAL (LD50): Acute: >10000 mg/kg [Rabbit]. DUST (LC50): Acute: &DERMAL (LD50): Acute: >10000 mg/kg [Rabbit]. DUST (LC50): Acute: >42000 mg/m 1 hours [Rat].gt;42000 mg/m 1 hours [Rat].


Potential Acute Health Effects:Potential Acute Health Effects: Slightly hazardous in Slightly hazardous in case of skin contact (irritant), of eye contact (irritant), of ingestion, ofcase of skin contact (irritant), of eye contact (irritant), of ingestion, ofinhalation.inhalation.

Potential Chronic Health Effects:Potential Chronic Health Effects:CARCINOGENIC EFFECTS: Not available. MUTAGENIC EFFECTS: Mutagenic for mammalian somatic cells. Mutagenic forCARCINOGENIC EFFECTS: Not available. MUTAGENIC EFFECTS: Mutagenic for mammalian somatic cells. Mutagenic forbacteria and/or yeast. TERATOGENIC EFFECTS: Not available. DEVELOPMENTAL TOXICITY: Not available. Repeated orbacteria and/or yeast. TERATOGENIC EFFECTS: Not available. DEVELOPMENTAL TOXICITY: Not available. Repeated orprolonged exposure is not known to aggravate medical condition.prolonged exposure is not known to aggravate medical condition.


Eye Contact:Eye Contact:

p. 2

Check for and remove any contact lenses. In case of contact, immediately flush eyes with plenty of water for at least 15minutes. Cold water may be used. Get medical attention.

Skin Contact:Wash with soap and water. Cover the irritated skin with an emollient. Get medical attention if irritation develops. Cold watermay be used.

Serious Skin Contact: Not available.

Inhalation:If inhaled, remove to fresh air. If not breathing, give artificial respiration. If breathing is difficult, give oxygen. Get medicalattention if symptoms appear.

Serious Inhalation: Not available.

Ingestion:Do NOT induce vomiting unless directed to do so by medical personnel. Never give anything by mouth to an unconsciousperson. Loosen tight clothing such as a collar, tie, belt or waistband. Get medical attention if symptoms appear.








Fire Hazards in Presence of Various Substances: Not applicable.

Explosion Hazards in Presence of Various Substances:Risks of explosion of the product in presence of mechanical impact: Not available. Risks of explosion of the product inpresence of static discharge: Not available.


Special Remarks on Fire Hazards: When heated to decomposition it emits toxic fumes.

Special Remarks on Explosion Hazards:Electrolysis of sodium chloride in presence of nitrogenous compounds to produce chlorine may lead to formation of explosivenitrogen trichloride. Potentially explosive reaction with dichloromaleic anhydride + urea.


Small Spill:Use appropriate tools to put the spilled solid in a convenient waste disposal container. Finish cleaning by spreading water onthe contaminated surface and dispose of according to local and regional authority requirements.

Large Spill:Use a shovel to put the material into a convenient waste disposal container. Finish cleaning by spreading water on thecontaminated surface and allow to evacuate through the sanitary system.


Precautions:Keep locked up.. Do not ingest. Do not breathe dust. Avoid contact with eyes. Wear suitable protective clothing. If ingested,seek medical advice immediately and show the container or the label. Keep away from incompatibles such as oxidizingagents, acids.

p. 3

Storage: Keep container tightly closed. Keep container in a cool, well-ventilated area. Hygroscopic



Personal Protection:Splash goggles. Lab coat. Dust respirator. Be sure to use an approved/certified respirator or equivalent. Gloves.

Personal Protection in Case of a Large Spill:Splash goggles. Full suit. Dust respirator. Boots. Gloves. A self contained breathing apparatus should be used to avoidinhalation of the product. Suggested protective clothing might not be sufficient; consult a specialist BEFORE handling thisproduct.

Exposure Limits: Not available.


Physical state and appearance: Solid. (Solid crystalline powder.)

Odor: Slight.

Taste: Saline.

Molecular Weight: 58.44 g/mole

Color: White.

pH (1% soln/water): 7 [Neutral.]

Boiling Point: 1413°C (2575.4°F)



Specific Gravity: 2.165 (Water = 1)







Dispersion Properties: See solubility in water.

Solubility:Easily soluble in cold water, hot water. Soluble in glycerol, and ammonia. Very slightly soluble in alcohol. Insoluble inHydrochloric Acid.



p. 4


Conditions of Instability: Incompatible materials, high temperatures.

Incompatibility with various substances: Reactive with oxidizing agents, metals, acids.

Corrosivity: Not considered to be corrosive for metals and glass.

Special Remarks on Reactivity:Hygroscopic. Reacts with most nonnoble metals such as iron or steel, building materials (such as cement) Sodium chloride israpidly attacked by bromine trifluoride. Violent reaction with lithium.




Routes of Entry: Inhalation. Ingestion.

Toxicity to Animals:WARNING: THE LC50 VALUES HEREUNDER ARE ESTIMATED ON THE BASIS OF A 4-HOUR EXPOSURE. Acute oraltoxicity (LD50): 3000 mg/kg [Rat.]. Acute dermal toxicity (LD50): >10000 mg/kg [Rabbit]. Acute toxicity of the dust (LC50):>42000 mg/m3 1 hours [Rat].

Chronic Effects on Humans: MUTAGENIC EFFECTS: Mutagenic for mammalian somatic cells. Mutagenic for bacteria and/ or yeast.

Other Toxic Effects on Humans: Slightly hazardous in case of skin contact (irritant), of ingestion, of inhalation.

Special Remarks on Toxicity to Animals: Lowest Published Lethal Dose (LDL) [Man] - Route: Oral; Dose: 1000 mg/kg

Special Remarks on Chronic Effects on Humans:Causes adverse reproductive effects in humans (fetotoxicity, abortion, ) by intraplacental route. High intake of sodium chloride,whether from occupational exposure or in the diet, may increase risk of TOXEMIA OF PREGNANCY in susceptible women(Bishop, 1978). Hypertonic sodium chloride solutions have been used to induce abortion in late pregnancy by direct infusioninto the uterus (Brown et al, 1972), but this route of administration is not relevant to occupational exposures. May causeadverse reproductive effects and birth defects in animals, particularly rats and mice (fetotoxicity, abortion, musculoskeletalabnormalities, and maternal effects (effects on ovaries, fallopian tubes) by oral, intraperitoneal, intraplacental, intrauterine,parenteral, and subcutaneous routes. While sodium chloride has been used as a negative control n some reproductivestudies, it has also been used as an example that almost any chemical can cause birth defects in experimental animalsif studied under the right conditions (Nishimura & Miyamoto, 1969). In experimental animals, sodium chloride has causeddelayed effects on newborns, has been fetotoxic, and has caused birth defects and abortions in rats and mice (RTECS, 1997).May affect genetic material (mutagenic)

Special Remarks on other Toxic Effects on Humans:Acute Potential Health Effects: Skin: May cause skin irritation. Eyes: Causes eye irritation. Ingestion: Ingestion of largequantities can irritate the stomach (as in overuse of salt tablets) with nausea and vomiting. May affect behavior (musclespasicity/contraction, somnolence), sense organs, metabolism, and cardiovascular system. Continued exposure mayproduce dehydration, internal organ congestion, and coma. Inhalation: Material is irritating to mucous membranes and upperrespiratory tract.





Toxicity of the Products of Biodegradation: The product itself and its products of degradation are not toxic.

p. 5





DOT Classification: Not a DOT controlled material (United States).

Identification: Not applicable.

Special Provisions for Transport: Not applicable.


Federal and State Regulations: TSCA 8(b) inventory: Sodium chloride

Other Regulations: EINECS: This product is on the European Inventory of Existing Commercial Chemical Substances.


WHMIS (Canada): Not controlled under WHMIS (Canada).

DSCL (EEC):R40- Possible risks of irreversible effects. S24/25- Avoid contact with skin and eyes.

HMIS (U.S.A.):

Health Hazard: 1

Fire Hazard: 0

Reactivity: 0

Personal Protection: E


Health: 1

Flammability: 0

Reactivity: 0

Specific hazard:

Protective Equipment:Gloves. Lab coat. Dust respirator. Be sure to use an approved/certified respirator or equivalent. Splash goggles.


References:-Hawley, G.G.. The Condensed Chemical Dictionary, 11e ed., New York N.Y., Van Nostrand Reinold, 1987. -SAX, N.I.Dangerous Properties of Indutrial Materials. Toronto, Van Nostrand Reinold, 6e ed. 1984. -The Sigma-Aldrich Library ofChemical Safety Data, Edition II.


Created: 10/11/2005 12:33 PM

p. 6

Last Updated: 11/06/2008 12:00 PM


LAMPIRAN K

DATA PERUSAHAAN

LAMPIRAN L

REKOMENDASI SIDANG

LAMPIRAN M

DAFTAR KEMAJUAN

TUGAS AKHIR

LAMPIRAN N

FOTO PENGUJIAN

LAMPIRAN O

BIODATA DIRI

BIODATA PENULIS

1. Judul Tugas Akhir : Analisis Laju Korosi dan Lifetime Pipa ASTM

A105 dengan Perbandingan Inhibitor NaNO2 dan Na2CrO4

2. Nama Lengkap : Titries Adistantria Mariami

3. NRP : 0815040061

4. Program Studi : D4 Teknik Perpipaan

5. Jurusan : Teknik Permesinan Kapal

6. Tempat/Tanggal Lahir : Surabaya/ 04 Januari 1997

7. Alamat Asli : Griyo Mapan Sentosa CB-23 RT01/RW07, Kel.

Tambah Sawah, Kec. Waru, Sidoarjo

8. E-mail : [email protected]

RIWAYAT PENDIDIKAN :

Sekolah dasar : SD Hang Tuah 10 Juanda / 2009

Sekolah Menengah Pertama : SMP Negeri 12 Surabaya / 2012

Sekolah Menengah Atas : SMA Dharma Wanita Surabaya / 2015

Perguruan Tinggi : Politeknik Perkapalan Negeri Surabaya / 2019

mailto:[email protected]