INDUSTRIAL TRAINING REPORTAT

ESSAR STEEL INDIA LTD, HAZIRA-SURAT.

PRESENTED BY

Raj Sudani

Faculty Of Technology & Engineering (KALABHAVAN).

The Maharaja Sayajirao University Of Baroda,

Vadodara, Gujarat.

ACKNOWLEDGEMENT

It is always a pleasure to remind the fine people in the Engineering Workshops for their sincere guidance we received to uphold our practical as well as theoretical skills in engineering.

Firstly, we would like to thank Mr. Gopalji Sinha (Head-ELC) and Mr. Nirali Purohit and Ms. Shweta Yemdey and Mr. Nilesh Hirpara(Manager-EOL) for providing us with the golden opportunity for training at CRM(Cold Rolling Mill) in ESSAR STEEL INDIA LTD -Hazira.

We express our deepest gratitude to Mr. Nitin Kulkarni(Head-CRM), Mr.Sushil Jamkhedkar, Mr. Anil Godhishala, Mr. Indraneel Sinha, Mr. Aditya Chaturvedi for their help and guidance and for giving prompt replies for our uncertainties regarding the plant.

Finally we express our sincere regards to all other unnamed who helped us in various ways to have an interesting and fruitful training.

CONTENTSI. Essar Profile

II. Introduction to Essar Steel

III. Process Flow Chart at Essar Steel Hazira.

IV. Process Flow Chart at Cold Rolling Mill

V. Cold Rolling Mill(CRM):

1. Pickling Process

2. Acid Regeneration Plant (ARP)

3. Roll shop

4. Continuous tandem cold mill (CTCM)

5. Six high reversible mill (CRM-1)

6. Electrolytic clean line (ECL)

7. Batch annealed furnace (BAF)

8. Cold skin pass mill (CSPM)

9. Continuous galvanizing line (CGL)

10.Cold Rolled Closed Annealed(CRCA)

Essar Profile

History

The Ruia family has been in business and in trading since the 1800s, when the family first moved to Mumbai from Rajasthan in western India. In 1956, Nand Kishore Ruia, the group founder, moved south to Chennai to begin independent business activities. In 1969 following the untimely demise of Nand Kishore Ruia, his sons Shashi and Ravi Ruia took over the group.

The name of company of "ESSAR" is getting from the first letter of two brothers "Shashi" and "Ravi" S as ESS and R as AR.

Overview

Essar is a multinational corporation with investments in Steel, Energy, Infrastructure and Services. With operations in more than 29 countries, it employs over 60,000 people.

- STEEL 

Essar has a significant global presence in steel and an international portfolio of iron ore and coal mines.

Essar Steel is a fully integrated flat carbon steel manufacturer – from iron ore to ready-to-market products – with a current capacity of 14 million tonnes per annum (MTPA) and a footprint in India, Canada, USA, the Middle East and Asia.

- ENERGY

Essar Energy is a world-class, low-cost, integrated energy company focused on India and positioned to capitalize on India's rapidly growing energy demand. The combined assets of Essar Power and Essar Oil constitute Essar Energy.

Essar Oil is a fully integrated oil and gas company of international scale with a strong presence across the hydrocarbon value chain – from exploration and production to oil retail.

Currently, Essar Oil India has over 700,000 barrels per stream day (bpsd) of global crude refining capacity at Vadinar, Gujarat, India and Stanlow, UK.

Essar Power is among India's top private sector power producers with a current generation capacity of 6700MW spread across eight power plants in India and Canada. 

- INFRASTRUCTURE 

Essar Ports is one of India’s largest owners and operators of ports in India and provides port & terminal services for liquid, dry bulk, break bulk and general cargo.

Essar Projects is a class-leading Engineering, Procurement and Construction (EPC) contractor offering innovative execution and delivery solutions.

Introduction to Essar Steel

Essar Steel is a global integrated steel producer with an annual capacity of 14 million tonnes with a strong presence in intensive steel consuming markets of Asia and North America. It has operations in four countries

A 10 MTPA integrated facilities in India.

A 4 MTPA steel plant in Canada.

A 7 MTPA Taconite plant under execution in USA.

A 0.4 MTPA downstream complex in Indonesia.

Essar Steel India is an integrated steel producer with an annual production capacity of 10 million tonnes. Essar Steel’s manufacturing facility comprises ore beneficiation, pellet making, iron making, steel making, and downstream facilities including cold rolling mill, galvanising, pre-coated facility, steel processing facility, extra wide plate mill and a pipe mill.

Essar Steel has set up a 1.5 MTPA plate mill and a 0.6 MTPA pipe mill at Hazira to add further value to its product portfolio. With one of India’s largest steel processing and distribution network with a capacity of 4 MTPA located at several industrial hubs.

DETAILS OF VARIOUS ESSAR STEEL PLANTS IN INDIAVizag 8.0 MMTPA beneficiation plant at Kirandul

267 km slurry pipeline Port based 8.0 MMTPA pellet plant

Paradip 12.0 MMTPA beneficiation plant at Dabuna 253 km slurry pipeline Port based 12.0 MMTPA pellet plant

Hazira 10 MMTPA steelmaking capacity; 3 distinct iron making units (DRI, BF & Corex)

Port based plant Steel Making Technologies:- 4.6 MMTPA Electric Arc Furnaces (4 units)- 5.0 MMTPA CONARC Furnaces (2 units) Product capacities- 7.1 MMTPA of Hot Rolled- 1.4 MMTPA of Cold Rolled- 0.5 MMTPA of Galvanized- 1.5 MMTPA Plate Mill- 0.6 MMTPA Pipe Mill

Pune 0.6 MMTPA Cold Rolling, 0.5 MMTPA Galvanizing & 0.4 MMTPA Color Coating facility

Process Flow Chart at Essar Steel Hazira

vvvcHBI + DRI

From MIDREX Process

H.M From COREX & BF

Steel Scrap

CONARC EAF

LF

CSP

PIPE MILL

HSMPLATE MILLPL

CONCAST

CRM

VD/VCD/RH Degasser

LF

INI caste

Process Flow Chart at Cold Rolling Mill Complex(CRM)

Hot rolled coil from HSM (Hot strip mill)

Pickling line - 1 Pickling line -2

HRPO

CTCM (Tandem mill)Six high cold rolling mills(CRM-1)

Cold rolled full hard (CRFH)

Continuous galvanizing line-2Continuous galvanizing line-1

Electrolytic Cleaning Line (ECL)

Batch Annealed Furnace (BAF)

Cold Skin Pass mill (CSPM)

CRCA product

GAL product

Roll Forming line-1 Roll Forming line-2 Auto CTL

GAL Finishing Line

Packing

Corrugation Line

LIR DMS ICTL FIMI

Pickling Process

Pickling is the chemical removal of oxide layer (scale) from metal by immersion in acid solution The hot rolled strip or sheet has surface oxidation or iron oxide which is very brittle, hard and has coefficient of friction. The surface of the strip is objectionable when they are to be further process.

Pickling is performed to remove hot rolled mill scales before any Cold rolling, Galvanizing or Painting operation.

In Pickling process HCL, H2SO4,and HNO3 used as pickling solution

Advantage of Hcl over H2so4:1. Considerably produce a uniform surface characteristics.2. Pickling rate is faster.3. It is cleaner to use and because if can be used at lower temperature due to

less fumes are evolved.4. Cost of heating bath is less because of lower operating temperature.5. Easily to handle as it available in 36% concentration.6. Rinsing is very easy because of high solubility of chlorides

Factor affecting rate of Pickling;

1. Acid bath concentration 2. Temp. of the acid bath3. Time in acid bath (line speed)4. Iron concentration in bath5. Agitation in bath 6. Presence of inhibitor7. Chemical composition of steel

Scale formation in hot rolling;In the hot rolling of carbon steel a layer of oxides forms on the surface of hot strip when the product leaves the mill typically at high temperature between 550.C and 900.C that forces oxidation and is coiled.

Steel coiled at a high temperature has thicker scale is layer (750.C=12 microns whereas 570.c = 6 microns) and composition of scale is largely influenced by cooling rate after cooling the faster cooling the higher proportion of wustite The scale on steel comprises three oxide of iron that differ proportion of oxygen.

Oxide layer of metal surface:Fe2o3Fe3o4

feo Base metal

Oxide layer Percentage of iron Percentage of oxygenFe2o3(hematite) 69.9 38.1Fe3o4(magnetite) 72.4 27.6

Feo(wustite) 77.7 22.3

Reaction occurrence in pickling:The purpose of pickling is remove scale from the metal surface The strip of plain carbon steel passed from the hydrochloric acid and then rinse with hot water.

After rinsing dryer is carried out. In this process reaction carried out which describe below:

Fe2o3 + 2HCl = Fecl2 + H2O

Fe3o4 + 8HCl = 2Fecl3 + Fecl2 +4H2O

Fe2O3 + 6HCl = 2Fecl3 + 3H2O

In most of cases Fecl3 is reduced by metallic Fe and hydrogen to Fecl2

Fecl3 + H = Fecl2 + HCL

Fecl3 + Fe = 3Fecl2

Pickling line specifications:Properties Line-1 Line-2

Capacity type 0.60 MTPA 0.80 MTPAType Pull and semi

continuousContinuous shallow type

Width 850-1025 (mm) 850-1550(mm)Thickness 1.60-6.00(mm) 1.60-5.00(mm)

Coil inner diameter 610mm 610mmCoil outer diameter 1000mm Max. 2020mm

Line speed 170mpm 150mpmPickling agent HCL HCL

Coil width 28 ton. Max. 28 ton. Max.

Defects after pickling;Defects Corrective action

Over pickling Decrease bat concentration, reduce line speed, reduce bath temp.

Under pickling Decease line speed, increase acid bath concentration

Yellow patches Check rinse spray action, check pH value of the water

Roll marks Check i/p quality, tensioned roll Scratches Check roll rotating, check scratches

input headTelescopicity Check EPC, check dust on EPC tube

Handling Damage Check strapping coil, proper storage of coils

Acid Regeneration plant(ARP)In acid regeneration plant mainly regeneration of hydrochloric acid from liquid product of pickling process. Liquid of pickling process mainly comprises Fecl3, Fecl2 and H2O. After process Fe particle and HCL are obtained Fe particle send for charging in blast furnace in iron making process and HCL send for pickling process. Chemical Reaction is carried as described below:

2Fecl2 + 2H2O + 1/2O2 = Fe2O3 + 4Hcl

In this plant heating done by combustion engine. Storage tank material is FRP(fiber resistance plastic)

Roll shopIn roll shop various type of process is take place such as grinding, overhauling, texturing, chocking-dechocking, lekage testing sand etc.

Roll material is forge steel which harden done by induction hardening so, outer layer of roll material is martensite which is very hard and inner layer of roll material is pearlite which is soft Roll mainly used for rolling operation

Roll grinder;ESSAR steel in CRM department mainly four grinder machine available which details as bellow;

Specification of roll Grinder-1:

Make - Herkules Franz Thomo

Max. roll diameter ]= - 640mm

Minimum roll diameter - 300mm

Roll speed - 120RPM

Grinding wheel speed - 1300RPM

Grinding wheel size - 750mm

Specification of roll grinder-2:

Make – Herkules Franz Thoma

Maximum roll diameter – 640mm

Minimum roll diameter – 380mm

Roll speed – 120rpm

Grinding wheel speed – 1300rpm

Grinding wheel size – 750mm

Specification of roll grinder – 3:

Make – Arrel Guist

Maximum roll diameter – 1500mm

Minimum roll diameter – 480mm

Roll speed – 26rpm

Grinding wheel speed – 1300rpm

Grinding wheel size - 915mm

Specification of roll grinder – 4:

Make – Waldrich Siegen

Maximum roll diameter – 1600mm

Minimum roll diameter – 380mm

Roll speed – 100rpm

Grinding wheel speed – 1600rpm

Grinding wheel size - 915mm

Specification of EDT Machine:

Make – Waldrich Siegen

Maximum roll diameter – 5500mm

Minimum roll diameter – 380mm

Roll speed – 35rpm

Overhauling:

Taper roller bearing – for CRM-1, CTCM & CSPM (work roll/IMR)

Cylindrical roller bearing – CRM-1, & CSPM (backup roll)

Margolis bearing – CTCM (Backup roll)

Ball bearing – CSPM Thrust Bearing

Leveler Table for bearing inspection

Large over hauling stand

Plunger leakage testing stand

Puller and tackles for different bearing

Chocking and Dechocking:

CTCM - Work roll

CRM-1 – Work roll

CRM-1 – intermediate roll

CSPM – Work roll

Six High Rolling Mill(CRM-1)

Mill specifications as given bellow:

1.Pay of Reel:

Material – Hot rolled and pickled low carbon steel

Thickness – 1.20mm to 4.50mm

Width – 700mm to 1270mm

Coil inner diameter – 508mm & 610mm

Coil outer diameter – 850mm & 2000mm

Unwinding speed – maximum 450 m/min.

Coil maximum weight – maximum 25T

Back tension – 500-5000kg

2. Three roll feeder:

Top Roll – 280mm*1400mm driven by A.C. motor

Bottom Roll – 280mm*1420mm fixed free roll

Bending Roll – 160mm*1420mm up down by hydraulic force

3. Mill Stand:

Finishing product thickness – 0.15mm to 1.60mm

Width – 700mm to 1270mm

Rolling speed – 1200mpm Max. at 400diameter work roll

Spindle Torque – 6046knm

4. Roll dimension:

Work roll – 400mm

Intermediate roll – 490mm

Backup roll – 1170mm

Purpose of 6 high rolling mill is reduction of thickness, finshing, and shape correction etc. During process for coolant oil and water mix use It is cold working process so, due to strain hardening steel become harden. Reason for strain hardening is interstitial atom, lower temperature etc. In this mill one stand for passing stand so, many time passing of sheet for rolling due to frequently passing of mill production of mill is very low as compare to tandem mill But advantage of this mill is that no require any lopper system, welding system etc. and require low working space.

In this mill width of sheet is not increase due to tension force which is given by DTR(delivery tension reel) and ETR(Entry tension reel) although width is increase in micron size but length of sheet is increase much more time as compare to original length. It is based on the plain stress and strain condition force applied on the roll it is done by hydraulic mechanism. Roll gap between two roll is depend on thickness sheet mainly 15% of thickness of sheet.

Continues Tandem Cold Mill(CTCM)

In CTCM(continues tandem cold mill) five stand and four high mill is available main advantage of tandem mill is high production as compare to six high reversible mill

Special future of tandem mill as given bellow:

1. Flush butt welder2. 90 degree turning point3. 6 stands 600 mts. Lopper4. L-2 automation5. Mill cleaning system6. Automatic flatness control7. Automatic thickness control8. DSR(Dynamic Shape Roll) in stand-5 better shape control9. Flying shear to cut sheet at 200mpm

Specification of tandem mill as given bellow:

1. Production capacity – 1.2MTPA2. Mill speed maximum – 1000max.3. Entry thickness of sheet – 1.55mm to 5mm4. Exit thickness of sheet – 0.2mm to 3mm5. Coil maximum weight – 28MT6. Coil width - 650mm (min.)&1625mm (max.)

In tandem mill starting portion is flash butt welder which is used for joining of tail of one coil and head of another coil. After welding head and tail of coil fill material

to each other after welding lopper portion is start. In lopper sheet turn at 90 degree. It is done by two roll which put at 45 degree mainly lopper fill 90% material at the end of coil

In lopper portion also put the bridle roll and steering unit work of bridle roll is creating tension in the sheet while steering unit control sheet at center line

After lopping mill portion is start. Initial thickness of sheet measured by x-ray gauge 1 and then one stand pass sheet and reduced thickness of sheet. In this mill only one time pass of mill. And then once again measure thickness of sheet. In this mill force is given to roll by using of hydraulic mechanism. The diameter of backup roll is 1350mm to 1500mm and work roll is 480mm to 560mm. Working temperature of this mill is around 50degree Celsius so, strain hardening phenomena occur and material become hard and dislocation produce. So, increase force of roll at further process. For cooling oil and water use.

In stand 5 roll put bright and matt surface that depend on further process. Final measurement of thickness also put x-ray gauge after completing cold rolling.

End of mill two tension reel which recoil of sheet. Mill cleaning done by hydraulic pump. After cleaning of surface strip measure the Ra value. It should be within 0.6 to 1.8 micron. If the Ra value below 0.6 than increase unit roll force for last stand while Ra value below the 1.8 reduced unit force for last stand

Thickness(mm) Rolling Mode Unit roll force0.3-0.5 Sheet thin 650+/-500.5-0.8 Sheet 650+/-500.8-1.0 Sheet 700+/-501.0-1.2 Sheet 700+/-501.2-1.5 Sheet 700+/-501.5-2.0 Sheet 750+/-252.0-2.5 Sheet 800+/-25

For work roll diameter variation with crown as given bellow:

Stand Max. dia.(mm) Min. dia.(mm) crown Roughness(Ra)

1 530 480 140+/-10 0.9+/-0.12 540 490 110+/-10 0.9+/-0.1

3 550 510 80+/-5 0.6+/-0.1

4 560 520 80+/-5 0.6+/-0.1

5 560 520 80+/-5 0.6+/-0.1for GAL & 3+/-0.2

for CRCA

For back up roll diameter variation with crown as given bellow:

Stand Diameter(mm) Cycle over tonnage

Crown Roughness(Ra)

1 1350-1500 75000T 160+/-180 1+/-0.22 1350-1500 75000T 160+/-180 1+/-0.23 1350-1500 75000T 140+/-160 1+/-0.24 1350-1500 75000T 140+/-160 1+/-0.25 1450-1500 75000T 140+/-160 1+/-0.2

Cycle over Tenure for work roll:

Stand-1 Stand-2 Stand-3 Stand-4 Stand-590KMS 300KMS 350KMS 450KMS 200KMS

(plain roll)0.6-0.7 Ra on strip surface for matte roll or 200KMS ever earlier

Electrolytic Cleaning Line(ECL)

The purpose of this line is to remove the residual oil and iron fines present of cold rolled strip This required to avoid carbon shoots and hydrogen shoots on the strip after annealing It requirement for auto and white good product

Specification of this line as given below:

Thickness – 0.25 to 3 mm

Width – 600 to 1625mm

Line speed – 270mpm

Strip tension - 12N/nm2

Oil & dirt (input) – 300mg/m2/face

Iron fines – 70mg/m2/face

Residual oil on strip:

Input – 250mg/m2/side

Output – 50mg/m2/side

Residual iron fines on strip:

Input – 50mg/m2/side

Output – 25mg/m2/side

To avoid the formation of insoluble cracking product during the annealing process The cold roll strip has following process will not be disturbed

This soiling can be rolling oils, rolling emulsions (natural synthesis, corrosion, additives etc.)

Sometimes also called tramp oils (hydraulic oil other oil during cold rolling process ) can be found

Furthermore iron fines and chemical reaction product as iron scale remove

This line based on the three law saponification, emulsification, deflocculating.

In saponification more particle concern fatty matters such as fatty acid exist on the strip. soda or potash saponifies the ester to form soaps that will be soluble in alkaline solution.

An emulsion is a mixture of two or more liquids that are normally immiscible (unmixable or unblendable). Emulsions are part of a more general class of two-phase systems of matter called colloids. Although the terms colloid and emulsion are sometimes used interchangeably,emulsion should be used when both phases, dispersed and continuous, are liquids. In an emulsion, one liquid (the dispersed phase) is dispersed in the other (the continuous phase). Examples of emulsions include vinaigrettes, milk, mayonnaise, and some cutting fluids for metal working.

Flocculation, in the field of chemistry, is a process wherein colloids come out of suspension in the form of flake; either spontaneously or due to the addition of a clarifying agent. The action differs from precipitation in that, prior to flocculation, colloids are merely suspended in a liquid and not actually dissolved in a solution. In the flocculated system, there is no formation of a cake, since all the flocs are in the suspension.

In this line alkali tank available which remove the iron fines and oil gets lessened at 85 degree Celsius and then brush scrubber remove the iron fines and then pass through ECL tank. In this tank strip become anode and cathode remove oil and then flow of water spray remove the solution of iron fine as well as oil and then passed for drying (hot air).

Batch annealed furnace(BAF)

It receive coil from the electrolytic cleaning line which material is very hard due to cold working process.

Purpose of this line is to relive internal stress produce during cold working process and the material is subjected to only recrystalise annealing temperature

In general material heated up to predetermined temp. it is known as recrystalisation temperature. And finally cool down slowly and we achieved desire property. The various property of treatment are to:

1. Relive internal stress 2. Improve restore ductility and toughness3. Enhance machinability4. Refine grain size and orientation5. Reduce gas content in steel6. Improve formability related property

Start process with charging in charging of coil put in the form of stack and final shape of stack of coil is kept cone, cylinder type. When different diameter of coil is available that time higher cross section are must kept at lower portion and lower cross section area of coil must kept at upper portion. This plate separated by diffuser plate for better convection process. This coil loaded on annealing bases after charge coil placed shell which is made by stainless steel. This shape is cylinder type it also called inner cover.

After clamping the inner cover ready for leak test. In this test find out leakage in the bases inner cover purge out of inert gas i.e. N2 gas which drive the O2

The base ensure free of any leakage and then ready for heating sequence. In heating sequence heating bell is enter on the inner cover furnace inert atmosphere should be H2 it reduce oxidation of the steel after heating complete for cooling another bell is entered. Which is called cooling bell in this bell hot air is removed and cold air enter

Heating of coil done by natural gas and air mixture. This mixture ready for combustion in 2 step high velocity burner here heating bell heat the inner cover by using of burner

During process recovery, recrystalisation, grain growth is occur after annealing grain become big grain so mechanical properties are recovered.

Process sequence in batch annealed furnace:

Heating cold roll strip recrystallisation temp. in inert atmosphere

soaking at this temp. for sufficient homogenization and necessary changes

Cooling at predetermine zone

Here pure H2 is used because

1. Very high conductivity2. Low viscosity3. High reducing potential4. Smaller molecular size5. High decarburizing power

Conduction, convection and radiation occur in furnace for heat transfer

Grain before annealing:

Cold Skin Passing Mill(CSPM)

Purpose of cold skin passing mill is

1. To suppress the yield point phenomena, 2. To increase roughness of the material, 3. Shape correction of sheet4. Cleaning of sheet

In cold skin pass mill thickness reduction of sheet occur in micron range which is negligible. Yield stress represent that deformation of material is gone elastic to plastic The reason of suppress the yield point is that coil will go for deep

drawing process in automobile industries that time deep drawing not occur and wrinkle produce. Also elongation of sheet is increase.

Roughness of sheet is also improve due roughness of roll is high. Here matt surface roll is used. So impression of roll put on the sheet. It is carried out because this coil will go for automobile industry which doing paint on the sheet. If roughness is low than sheet can not be old down the paint so, roughness impart is necessary.

Cleaning of sheet is done because rust resistance is increase.

Shape correction also take place on this mill. Shape defect produce during backward process of coil such as waviness, center braking, quarter etc.

Raw material of this process is low carbon steel which emerge in batch annealing furnace. In this type mill comprises mainly 4- roll for process such as two backup roll and two work roll, anti crimping roll, wet temper unit, pay of reel, tension reel, various type of gauge.

First of coil is entered in mandrel of pay of reel. Then bridle work for increase in tension then gauge measure the dimensions of sheet. Then wet temper nozzle start to flow of cooling media(oil and water). Then sheet pass from the roll air wiper flow of air to remove cooling media and then tension reel uncoil the sheet.

Benefits of Wet temper unit:

1. Prevention of iron fines on work roll2. Good corrosion preventing properties3. Lubricant properties4. Good staining preventing properties

Rust preventive unit:

Type of oiler – Electrostatic high tension

No. of coil reservoir – 3

Oil used – FUCHS 4107-S

Temperature reservoir – 65-75degree Celsius

Temperature spray bar – 70-80degree Celsius

Benefits of electrostatic unit:

1. Uniform coating2. Significant oil saving

3. Coating weight flexibility4. No mechanical contact5. Coating material transfer efficient

Here mainly low carbon material is used for this mill so in microstructure in ferrite and pearlite is available. Grain size of material is high after passing material in mill grain size become elongated in elliptical shape.

Continuous Galvanizing Line(CGL)

After rolling under cold roll mill then coil will go for coating in galvanizing plant. Here zinc coating take place on the coil. For galvanizing two line is available. GAL-1 and GAL-2

Specification of Gal-1 line:

1. Input material – cold rolled/hot rolled low carbon including structural steel2. Strip thickness – 0.30mm to 3.25mm3. Strip width – 800mm to 1370mm4. Coil inner diameter – 508/610mm5. Coil outer diameter – 1800mm6. Line speed – 180mpm

Specification of Gal-2 line:

1. Input material – cold rolled/hot rolled low carbon including structural steel2. Strip thickness – 0.12mm to 0.60mm3. Strip width – 700mm to 1250mm4. Coil inner diameter – 508/610mm5. Coil outer diameter – 1800mm6. Line speed – 150mpm7. Coil weight – 22T(max.)

Here two uncoiler for process after uncoil the coil is gone for welding. GAL line type of welding is seam welding which is high frequency resistance and it is operated by electric current. And then coil pass through bridle which create tension in the sheet. Here lopper also available in GAL-1 lopper is horizontal while in GAL-2 lopper is vertical. After lopping coil go for process section.

In process section first coil heated in the furnace. Five zone in furnce is available just like

1. Preheating zone2. Direct fired furnace3. Radiantive furnace4. Soaking zone5. Jet cooling furnce

In preheating zone mainly coil heated up to 400 to 500 degree Celsius. for combustion natural gas and air is mixed. In direct fired furnce have also sub zone in zone 1, 2, 3 eight burner is available and in zone 4 64 burner is available for heating. In radiative furnace strip heated by radiation of heat. In this zone tube for heating is available which is made up of copper. In soaking zone 48 burner is available. In last zone five blower for GAL-1 and 3 GAL-2.

Heated strip pass in zinc bath. Chemistry of zinc bath is

Al – 0.143 to 0.030%

Pb – 0.05 to 0.15%

Zn – balanced zinc

Working of al is control the reaction of the Zn and steel strip because this reaction between Zn and steel is high diffusion occur. Charging of bath is Zn ingot. High grade zinc, prime western zinc and al alloy. In bath three roll also available such as sink roll, seal roll and stabilizer roll. Sink roll give tension to strip for going in upward direction. Seal roll seal the zinc coating. And stabilizer

roll maintain excess zinc coating. Mainly two type dross is obtained 1. Bottom dross and 2. First dross

After coating strip go for pot cooling. In cooling done by water quench. And then coated zinc strip pass through chromic acid at high temperature. Chromic acid increase life of zinc coated strip.

And then coil is again recoiled. And go for finishing line.

microstructure of Zn coated material:

In GAL finishing line two lines available:

1. Corrugation2. Cut to length

In corrugation line roll forming line which produce corrugated shape in strip.

In figure one is represent the trapezoidal shape while in figure two is sinusoidal

CRCA Finishing LineThe CRCA finishing Line is last unit of CRM plant where various type coil finished such as HRPO, CRFH, GAL, CRCA. After passing this line coil pack and go to costumer.

CRCA finishing line is four which describe as bellow:

1. DMS(Dujardin Montbard Somenor) line2. LIR line3. .FIMI line4. ICTL(inspection cum trimming line) line

Various Processes are take place:

1. Shearing2. Trimming3. Parting4. Slitting5. Inspection

Specification of DMS line:

1. Make – D.M.S. France2. Capacity – 69900MT/Annum3. Strip Thickness – 0.3 to 3 mm4. Strip width - 500 to 1300mm

5. Slit Width – 250mm min. 5 pieces max.6. Yield Strength – 42kg/mm2 max. up to 3 mm

Specification of FIMI line:

1. Make – FIMI Italy2. Capacity – 140000 MT/Annum3. Strip Thickness – 0.3 to 3 mm4. Strip Width – 400 to 1600mm5. Shear Length – 1000mm to 3500mm6. Yield Strength – 42N/sq.mm

Specification of LIR line

1. Make – D.M.S. France2. Capacity – 180000MT/Annum3. Strip Thickness – 180000 MT/Annum4. Strip Width - 0.4 to 2.5 mm5. Slit Width – 300mm min. – 3pieces max.6. Yield Strength – 45kg/mm2 max. up to 3mm thick

Specification of ICTL line:

1. Make – Dong Bang Korea2. Capacity – 300000MT/ANNUM3. Strip Width – 600 to 1650 mm4. Strip Thickness – 0.3 to 3mm5. Trim Width – 1000mm min. – 1 pieces6. Yield Strength – 45kg/mm2 max. up to 3mm thick