1

Introduction

Durgapur steel plant is the third integrated Steel plant of the Steel Authority of India Limited to come up under public sector in India. The plant was set up with an initial capacity of 1 million tones per annum of crude steel by a group of British companies in the late 50s. It was later expanded to 1.6 MTPA in late sixties. Later on SAIL decided to modernize DSP with government approval in 1989 and the present capacity is 2 MTPA of hot metal.

Durgapur was selected as location of an industrial steel plant, because of its

proximity of coal fields, the Grand Trunk Road, Calcutta- Delhi main railway track, Calcutta port, power from Damodar Valley Corporation and water from Durgapur Barrage on river Damodar.

The plant started iron production on 26th Dec, 1959. The Plant produces Wheels & Axles mainly for Indian Railways. The other products are Light & Medium Sections, Merchant Products, Skelps, Blooms and Billets. All the production departments of the plant are covered by ISO 14001:2004 EMS and OHSAS 18001 certification.

Historical Background

It is said that Durgapur is the child of independence. An outcome of a strong desire to become self sufficient in steel and strengthen the core sector of Indian economy. Even in late 50s, the crude steel output in our country was as low as 1 million ton per annum.

In early 50s, India went for rapid industrialization under our visionary Prime

Minister Pandit Jawharlal Nehru. It was realized that steel was one of the most important ingredients for rapid industrialization of India and a number of Steel Plants came into being in the country. Dr. Bidhan Chandra Roy, the first Chief Minister and the architect of modern Bengal dreamt of setting up an integrated steel plant at Durgapur. The idea was subsequently firmed up as a follow up recommendations of Colombo Plan Mission. The contract to construct a steel plant in Durgapur was awarded to a consortium of thirteen British Companies Indian Steel Works Construction Company Limited (ISCON) in October 1956. Sir Cyril E Jones was the Chairman of ISCON and Mr. D J Bell was the Resident Director at site. Mr. K K Sen was the first General Manager of Durgapur Steel Project.

A total of 6,568 hectares of land was acquired and the construction begun at the

site in January 1957. Durgapur Steel was braught under Hidustan Steel Limited on April 1, 1957. The first Blast Furnace, Kasturba, was dedicated to the nation by Dr. Rajendra Prasad, the first President of India on Dec. 29th, 1959. The Plant cast its Steel Ingot on April 24, 1960. In 1965-66 the plant recorded its first Net Profit of Rs.29 Lakhs. Later on capacity expansion of DSP to 1.6 million tonne per annum was

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completed in the year 1968-69. Further modernization of DSP was taken up with production capacity of 2.088 MT of hot metal, 1.802 MT of crude steel and 1.586 MT of saleable steel. This process of Modernization of major units was commissioned by April 1996.

General Overview of DSP

Durgapur Steel Plant (DSP) is a unit of the PSU steel major Steel Authority of India Limited - Indias largest steel producer. SAIL operates and owns five integrated steel plants at Bhilai, Durgapur, Bokaro, Rourkela and Burnpur and three specialty steel plants at Salem, Durgapur and Bhdravati. DSP is an integrated steel plant having major units like Raw material Handling Plant, Coke Ovens. Sinter Plant, Blast Furnace, Steel Melting Shop, Continuous Casting Plant, Rolling Mills and Wheel and Axle Plant. The iron ore are received, stacked and reclaimed at Raw Material Handling Plant. A part of iron ore (especially iron ore fines) are sent to Sinter Plant for agglomeration, while the lump ore is sent to Blast Furnace. Another important raw material is coal, which is converted into coke at Coke Ovens. Sinter, coke and lump ore along with flux material are charged into Blast Furnaces for making hot metal. Hot metal is converted into steel by blowing Oxygen at Steel Melting Shop. Liquid steel produced at SMS are primarily cast into blooms and billets at Continuous Casting Plant. The blooms and billets are further processed /rolled at different mills for producing different finished products. Some part of the blooms and billets are also as semis in the market. A part of liquid steel is also cast as bigger size ingots, which are further processed/rolled as finished products. Hence DSPs products can broadly be categorized in two groups- finished and semis. DSP has an important contribution towards SAILs overall product basket.

Durgapur Steel Plant situated at distance of 158 km from Calcutta, the geographical location is 23 27 north and 88 29 east. It is situated on the banks of the river - Damodar. The plant, spread over an area of 6.5 sq km, employs a workforce of about 15,200 people.

Major Product Profile The main products of Durgapur Steel Plant are as follows:

Products Application Finished products TMT Bars & Rods Construction & Fabrication Medium Structural (Angle, Channels and Joists)

Construction & Fabrication

Wheel & Axles Railways Skelp Tube Manufacturing Semis : Blooms, Billets & Slabs Re-rolling & Forging

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Major Highlights:

1.95

2.06

2.19

1.8

1.85

1.9

1.95

2

2.05

2.1

2.15

2.2

2005-06 2006-07 2007-08

Blast FurnaceHot Metal (MT)

105% of rated capacity utilisation

1.67

1.7

1.72

1.64

1.65

1.66

1.67

1.68

1.69

1.7

1.71

1.72

2005-06 2006-07 2007-08

Saleable Steel (MT)

108% of rated capacity utilisation

1.8

1.87

1.91

1.741.761.78

1.81.82

1.841.861.88

1.91.92

2005-06 2006-07 2007-08

Steel Melting ShopCrude Steel (MT)

106% of rated capacity utilisation

65838

66532

68800

6400064500650006550066000665006700067500680006850069000

2005-06 2006-07 2007-08

Wheel & Axle(Nos)

68,800 wheels supplied to Indian Railways

296.4

295

302.3

290

292

294

296

298

300

302

304

2005-06 2006-07 2007-08

Coke Ovens(Pushing per day)

302.3 pushing per day

142.6

195.4 208

0

50

100

150

200

250

2005-06 2006-07 2007-08

Labour Productivity(t/man/year)

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Process Flow Diagram

Lime Stone, Dolomite, Iron Ore, Ferro Mn, Ferro Si, Silico Mn

Raw Material Handling Plant

Lime Stone

NLCP Iron Ore Lump

Sinter Mix

Sinter Plant

Sinter

Coal

Coal Handling Plant

Coke Oven

CO Gas

Coal Chemicals

Blast Furnace Coke

Slag SGP

Clean Gas

Benzene, Toluene, Light Solvent Napta, Napthalene, Creosote Oil, Crude Tar, Ammonium Sulphate, Light Oil

Pig Iron PCM Scrap Scrap

Yard

Return &

Process Scrap

O2, Ar, N2 O2 & N2 for Sale

Oxygen Plant

Hot Metal Lime FeSi FeMn Dolo I/Ore Lump

Steel Melting Shop (BOF)

Liquid Steel

CCP Bloom Caster

Blooms for Sale

Teeming Stage Wheel Ingots Spl Casting Bay

Stripped Wheel Ingots

W & A Plant

Wheel & Axle for Railway Carriage

8 T Ingots

Striper Bay

Stripped Ingots Blooming

Mill Blooms

Billet Mill

Billet & Slabs for Sale

Section Mill Skelp Mill Merchant Mill

Rolled Billets

Rolled Slabs

Plain Rounds & Ribbed Rounds

(TMT Bars)

Steel Strip / Skelp Angles, Channel, Joist

Granulated Slag

CC Billet for Sale

Billet Caster

Continuous Casting

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Major Production Departments Raw Material Handling Plant

Raw Material Handling Plant is the starting point of steel making process. The objective of RMHP is to receive, load, unload and places all the raw materials required for steel making i.e. Iron ore, Limestone, and Dolomite. Apart from this, RMHP also deals with Sinter mix preparation using state of the art automation system.

Iron ore, coal and limestone are the three basic raw materials for the steel industry. Durgapur Steel Plant draws its coal from the adjacent Jharia-Ranigunj coal belt. A good amount of prime coking coal, having fairly low ash content, is also imported. Bulk of iron ore lumps and fines come from the mines at Bolani in Orissa. Lime stone comes from a variety of sources: Birmitrapur (Orissa), Jaisalmer (Rajasthan).

Major functions of RMHP: 1. Tippling of wagons. 2. Stacking and reclaiming of raw materials. 3. Crushing of flux and coke. 4. Sinter mix preparation. 5. Blend mix supply to sinter plant. 6. Iron ore lump screening. 7. Screened iron ore supply to blast furnace. 8. Limestone, dolomite & iron ore lump supply to BOF.

Material Flow Diagram:

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Major Equipments used:

Equipments Nos Functions Wagon tipplers 3 To unload the raw materials brought in rails of wagons

from various mines Wing Tipplers 3 To stack material on the beds Old Reclaimers 4 This Plough and Harrow type reclaimers are used for

reclaiming the materials Stacker cum Reclaimer

4 For stacking on beds as well as reclaiming from beds (Two beds for Iron ore and three beds for flux)

Slew able Stacker

1 For sinter-mix preparation (i.e.) stacking for blend mix.

Blender Reclaimer

1 To reclaim the blend mix

Sources of raw materials:

Raw material Size (in mm) Main source Iron ore fines 0-10 Bolani Ion ore lump 10-50 Bolani BF/SP gr. L.S 5-50 Birimitrapur BF/SP gr. dolo 5-50 Birimitrapur BOF gr. L.S 25-55 Jaisalmer Coke breeze 0-20 Internal

Coke Oven & Coal Chemicals

The coke ovens and coal chemicals zone is divided into four basic sections namely Coal Handling Plant, Battery, Coke Handling Plant and Coal Chemicals. Presently, DSP is operating only 3 full batteries out of total 5 full and one batteries where each full battery consists of 78 ovens.

The Blast Furnace grade coke produced in Coke Ovens is directly used in Blast Furnaces while the undersized coke is used for sinter making.

The volatile matters, which emanate during the process of coke making subsequently produce a variety of by-products like naphthalene oil, heavy creosote oil, light oil, crude tar partially distilled tar, Ammonium Sulphate fertilizer in brand name Raja, nitration grade benzene, nitration grade toluene, industrial grade toluene, light solvent naphtha etc.

The coke oven gas is generally used in combination with the Blast Furnace gas and BOF gas as fuel and is carried through pipelines to the different areas of the plant. The adjoining Alloy Steels Plant under SAIL is also supplied with this fuel gas from DSP.

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Material Flow Diagram:

Coal Handling:

Aim of this unit is to supply coal of required quality and quantity to service bunkers for BF coke making. Here washed coal and imported coal received in wagons are unloaded by means of 3 nos. of Box Tipplers. The tippled coal is then stacked in 14 nos. of silos as per quality and grade. Coal of different quantity is drawn from Blending silos and selectively crushed and blended in selective crushing unit. Thus blended quality coal is sent to service bunkers at battery top for BF coke making.

Coal Handling Plants has three major sections. These are : 1. Tippling Sections Major Equipments Box Tipplers - 3 nos Wing Trippers - 6 nos (4 old + 2 new) Stacking Beds - 12 nos Conveyors - 10 kms long approx. 2. Reclaiming Sections Major Equipments Old Reclaimers - 4 nos New Reclaimers - 3 nos Blending Silos - 14 nos Conveyors - 12 kms long approx. 3. Selective Crushing Unit Major Equipments Primary Crusher - 4 nos Secondary Crusher - 2 nos Pneumatic Classifiers - 4 nos Conveyors - 12 kms long approx.

Coal Handling Plant

Batteries Coal Chemicals

Coke Handling Plant

B.F.Coke (+20 80 mm)

Nut Coke (+10 20 mm) Coke Breeze (0 10 mm)

Benzene Toluene Light Solvent Naptha Light Oil Napthalene flake Creosote Oil Crude Tar Ammonium Sulphate CO gas

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Coal Handling sections also attached with Coal Washery where raw coal is washed to reduced its ash content before using it blend preparation. The main units of Coal Washery are Heavy Media Bath, BATAC jig, Spiral Washer, Thickener and Filter. Presently Coal Washery is not working.

Coke Oven Battery:

There were 3 batteries of 78 ovens each and a half battery of 39 ovens. Capacity of each oven is 20 tonnes approx. on dry basis. The standard coking time is 18 to 20 hours. The flue temperature is 1230 C. Resulting Coke of size 20 to 80 mm sent to BF and undersize coke is sent to RMHP.

There are 4 special cars in this section: (a) Charging car: Takes coal from service bunkers to individual ovens (b) Ram car: Pushes the coke out of individual ovens (c) Guide car: Guides the coke during pushing operation (d) Quenching car: Receives the hot coke for quenching

Coke Handling Plant: At Coke Handling Plant the coke is screened for BF Coke, i.e. +20mm 80 mm and sent to Blast Furnace. Coal Chemical Plant:

This is a byproduct plant which recovers the chemicals from the gas and allows clean gas to be used in coke ovens and other plant as fuel. There are 4 gas streams with capacity of 3300 cubic meter/Hr each.

Coal Chemical Plant has four major sections:

(a) Benzol Plant produces Benzene, Toluene, Heavy and Light solvent Naptha. (b) Tar distillation Plant produces Light Oil, Napthalene Oil, Heavy Creosote

Oil, Crude Tar Partially Distilled (CTPD). (c) Mechanised Napthalene Crystallisation Plant (MNCP) produces Napthalene

flakes. (d) Biochemical Oxygen Demand Plant (BOD) Liquor and waste water of the

plant is treated here with bacteria to destroy different poisons before it is allowed to pass to the outfall.

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Sources of different types of Coal:

SINTER PLANT

Raw Sinter is a hard porous lump produced by controlled heating of a mixure of Iron ore fines, lime stone fines, dolomite fines, coke fines and other waste materials. Usage of sinter in Blast Furnace offers many advantages, like, utilization of Iron ore fines (which otherwise cannot be used directly in Blast Furnace as it will choke the furnace due to its fineness), reduction in coke rate etc.

The process of sintering started in 1910 and flourished in different countries where

there was coke shortage. Advantages of using sinter are:

(a) To utilize all waste of fines nature like Mill scale, Ferro Scrap, LD slag etc. (b) To reduction in coke rate in Blast Furnace (c) To increase productivity of blast furnace (d) To provide smooth Gas Dynamics inside BF stack. (e) To utilize Iron Ore fines and Coke breeze. (f) Better Operation of Blast Furnaces as Sinter is engineered product. Plant capacity: 3.009MT/annum Machine capacity: Sinter Plant 1 - 2500 T/day (for each old m/c) X 2 nos Sinter Plant 2 - 5184T/day (for new machine) X 1 no

Coal

Indigeneous Imported

PCC MCC PCC (Hard) MCC (Soft)

Patherdih

Sudamdih

Bhojudih

Jamodoba

Munidih

Dugdha

Kathara

Kedia

Swang

Rajarappa

Australia

China

USA

NZ

Austrtalia

Indonasia

PCC Prime Coking Coal, MCC Medium Coking Coal

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Material Flow Diagram: Major equipments:

Equipments Purpose Nodulizing Drum Moist charge is rolled to nodulise the fines and decrease the

size range of particles and consequently improve the permeability of sinter bed.

Sintermix Hopper To store the nodules before feeding to sintering machine. Sintering machine Sinter mix is spread over hearth layer, which is a layer of

previously sintered material. Material is heated under a set of burners and suction is applied from bottom. The heat travels down the bed and by the time the material reaches the discharge end, the whole mass is sintered.

Sinter Breaker Sinter is crushed here. Sinter Cooler Sinter is cooled here from 800 900 C to less than 100 C. Sinter Screen Through screening, sinter is separated out depending on size.

Sinter plant is a Heavy Power consuming plant and it consumes about 1/4th of the

total power. There are four electrostatic precipitators in Sinter Plant 2 and two electrostatic

precipitators in Sinter Plant 1 to control both fugitive and stack emission. Now target Sinter in Blast Furnace burden is 70 - 75%.

Various fractions of sinter are used as follows: +25mm and +6 to -16mm Blast furnace +16 to -25mm Hearth layer

-6mm Return fines re-circulated in sinter plant

Bunkers

Nodulizing Drum

Sintermix Hopper Drum Feeder

Screen Sinter Cooler

Sinter Breaker

Sinter Machine

Return Fines -6 mm

+6 to -16 mm for

Blast Furnace

+25 mm to Blast Furnace

+16 to -25 mm for Hearth layer

Blend Mix, Dolomite Fines, Lime Fines, Coke Fines,

Return Fines

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Blast Furnace

Blast furnace is the most important part of an Integrated Steel Plant. The objective of Blast Furnace is to take the raw material from RMHP, coke and sinter plant and convert it into pig iron or Hot Metal. Coke serves as the heat source and reducing agent while Limestone and Dolomite are used as flux, which combines with gangue to produce slag. A Blast Furnace is so called because it uses Air Blast as oxygen source for the process.

There are four Blast Furnaces in DSP, named Kasturba, Kamala, Sarada, Durga out of which three are running except Kasturba. Material Flow Diagram: Process:

Raw materials like Iron ore, sinter, coke are charged into the furnace from top in

required proportions called burden. Air enriched with oxygen is preheated in stoves. Preheated air is blown through Tuyeres in the bosh region. These are symmetrically located openings. The raw material descending through various temperature zones are heated up and get smelted. The reducing gases rise up through burden and go out through ascension pipes. The hot metal and slag obtained by smelting of raw materials trickles down and accumulate in the hearth which is the bottom most part of the furnace. The slag being lighter than hot metal floats on it.

The hot metal and slag are tapped through tap holes drilled using drilling machines and separated using skimmer plate in the trough. The hot metal thus obtained is sent to SMS to make steel or to PCM to make pigs. The slag is either dumped in the slag yard or granulated in slag granulation plant (SGP).

Blast Furnace Hot Blast

Sinter Iron Ore

Lump Coke

Gas Cleaning Plant

Slag

SMS PCM

Primary Dust Catcher

Secondary Dust Catcher

Washer

Electrostatic Precipitator

Clean gas with dust

10mg/NM3

BF Gas with dust 25 27 gm/NM3

Pig Iron

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BFs 3 and 4 have SGPs and hence the slag coming out of these BFs is granulated.

The gas ascending through the descending column is called BF gas and has high calorific value of 850 Kcal/Nm3. It is used as fuel at many departments in the plant. This gas has to be cleaned before being used as fuel. For this purpose, a gas cleaning plant is located in the Blast Furnace area.

Gas Cleaning Plant:

The gas coming out of Blast Furnace has a calorific value of about 850 KCal/NM3 and contains about 25-27 gm/NM3 of dust. Unless it is cleaned, it can not be used as fuel. The cleaning process is done in four stages. In the first stage, the gas is subjected to a sudden expansion in primary dust catcher. Then, it is given a cyclonic motion in a secondary dust catcher. The gas coming out at this stage has about 5-7 gm/NM3 dust. In the third stage, the gas is counter currently washed with water in gas washers. The gas coming out is then sent into a set of electrostatic precipitators, where it is cleaned to the maximum extent. The gas leaving ESPs has a dust content of 9-11 mg/NM3. The dust laden water coming out of the gas washer and Electrostatic precipitator is taken to Dor Clarifier, cooled and recirculated. The slurry is taken to Slag bank.

Furnace Details #1 #2 #3 #4 Capacity (TPD) 1820 1820 2340 Useful volume (m3) 1400 1400 1800 No. of stoves 3 3 3 Productivity

Presently not

working 1.3 1.3 1.3

Design parameters:

Parameters BF #2 & 3 BF # 4 Blast Temperature 1100 c 1150 c High top pressure 0.7kg/cm2 0.7kg/cm2 Sinter charge 75% 75% Furnace Productivity 1.3 1.3 No. of cast/day 9-10 9-10 No. of tuyers 18 20 No. of tap holes 2 2 Blast period 60 minutes 60 minutes

The slag contains CaO which is used for Cement manufacturing. This slag is sold outside. Granulated slag fetches better price. There are two Slag Granulation Plant (SGP) for BF #3 and BF #4.

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SMS Complex

SMS or Steel Melting Shop is the section where hot metal from blast furnace is converted into steel.. This type of Basic Oxygen Furnace was first used successfully in the places called Linz and Donawitz in Austria. The shop was added during modernization of DSP and has a capacity of 1.876 million tones per annum. SMS can be divided into 3 sections:

(a) Basic oxygen Furnace (b) Continuous Casting Plant (c) New Lime Calcination Plant

Basic Oxygen Furnace (BOF):

Hot Metal coming out of the Blast Furnaces is collected in ladles which are

transported through rail and is poured into mixers. There are two nos. of mixers which serve the purpose of storing as well as homogenization of temperature and composition of hot metal. Coke oven gas is used here to maintain the temperature at around 1260 C.

The shop has three converters each having a capacity of 110-130T. The average life

of a converter is around 1800 heats. Oxygen is blown at high pressure into the converter through a lance for steel making. The oxygen blowing rate through the lance is 415 Nm3/min. and the blowing pressure is 14.2 to 14.3 bar. The tap-to-tap time of BOF is approximately 57 minutes out of which oxygen blowing time is approximately 18 min. The gas obtained from BOF converter has a calorific value of 2100 Kcal/Nm3 and is used as fuel. The tapping temperature at Converter for CCP is 1700 C and top pouring temperature is 1640 1650 C. BOF has an online process automation system. The system uses VAX/VMS system which works on the principle of virtual memory. The whole data acquisition system contains various levels where the higher level caters to the need of quick retrieval of data about operation parameters and other activities.

Continuous Casting Plant (CCP): DSP has two billet casting machines & one bloom casting machine. In Continuous Casting Process, ladle containing liquid steel is kept on an arm of a moving turret. The liquid steel is allowed to fall on tundish, which acts as a distributor of liquid steel into 6/4 moulds in billet/bloom casting machine. The moulds are made of Copper and is cooled by demineralised water. It is a primary cooling wherein liquid steel does not come in direct contact with water. The initial formation of billet is made inside the mould itself. Once the newly formed Billet/Bloom leaves the mould it is subjected to secondary cooling or direct cooling in next stages. The Billets/Bloom are drawn out with the help of Withdrawl unit. The Billets/Blooms are cut into required sizes with the

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help of mechanical shear/gas cutting torch. The Billets/Blooms are subsequently evacuated and cooled in air and stacked for dispatch. The Continuous Casting Process is an energy efficient process with better yields. It converts liquid steel into billets/blooms directly and thereby saves substantial energy and process time. It also leads to better quality. There are two billet casters each with six strands capable of producing billets of sizes varying from 80mm2 to 150mm2. Presently only 100 mm2 and 125mm2 billets are produced with the length of 9 meters. The average casting time is 85 mins. There is one Bloom Caster with 4 strands capable of producing blooms of size 160 mm x 210 mm, 160 mm x 230 mm, 200 mm x 200 mm, 150 mm x 300 mm, 150 mm x 350 mm with a cutting length of 3.4 to 10 mtrs. New Lime Calcination Plant (NLCP):

This plant came up to cater to the need of BOF. The main function of this plant is to produce lime from naturally available limestone. Lime is mainly required for slag formation during the steel making process. Presently, Limestone from Jaisalmer is used as input material for the plant.

There are three kilns (annular shaft type), each having a capacity 300T/day. The kilns are vertical cylindrical structure. Limestone, which is charged from the top, descends through the kiln, where it is subjected to controlled heating by two firing zones. Coke Oven gas at 5500mm water pressure is used as fuel for heating. Thus it operates in the temperature range of 1200-1250 C.

The calcination process is almost over as the charge reaches the bottom portion of lower combustion zone and the calcined lime is discharged into a silo by lime discharging device. NLCP has got bunkers and conveyors for storage, handling and supply of fluxes to the converter shop.

BLOOMING & BILLET MILL

Main objective of this mill is to produce square and rectangular section called blooms. The 8T ingots produced at the SMS, are first sent to the stripper bay. The stripped ingots are reheated for hot rolling process to give them different sizes. Sections above 125x125, are called blooms while sections below 125x125mm are called billets. Some blooms go to section mills and rests go to billets mill. From Billet Mill slabs go to Skelp Mill.

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Material Flow Diagram:

Process:

Soaking pit furnaces are used for reheating the ingots at 1280C. There are 20 soaking pit furnaces with capacity 110T. Fuel used is CO gas + B.F gas in the ratio of 1:4. The reheating time is usually 1.5 times the track time. After soaking the ingots are lifted by means of vertical ingot charger cranes for soaking. It is a two high reversible type mill driven by two nos 3000 HP DC motor at the mills speed of 0/40/60 rpm. Here 1200T shear is used to cut fish tail, and then the blooms are put in the bloom transfer bank.

There is a two high reversible mill driven by 4500HP DC motor. The rolls are

counter weight balanced and driven with a speed of 0/80/120 rpm.

Pit Time:

This is the amount of time the ingots have to be placed in the soaking pits. This is equal to 1.5 times the track time, which is around 3 to 4.5 hrs for hot ingots and around 12 hrs for cold ingots .

No. of passes in 42 mill:

13 , in case of normal steel and 19 , in case of special steel.

Stripped Ingots from

Stripper Bay

Soaking Pits

Reheated Ingots 2 X 42 High Reversing Mill

1200T Shear

2 X 32 High Reversing Mill

700 T Shear

Cropped Ends to SMS

Blooms for Section Mill, Axle plant & Outside sale

Bloom Stock Bay

Up & Down Cut Shear

Mill Train Stands

Flying Shear

Cooling Bed

Billet Mill Despatch Billets for

Skelp Mill & Outside Sale

Reheating Furnace

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Major Equipments: v Soaking Pits: 20 in numbers and of 3 types v 42 Blooming Mill - 2 high reversing type with twin motor drive. v Primary Hot Bloom Shearing. v 32 Intermediate Mill - 2 high reversing mill driven by 4500 HP DC motor. v 700 T Shear

Billet Mill

Blooms produced in Blooming Mill are further rolled into slabs and billets of various sizes. The capacity of Billet Mill is 0.957 tonne per annum. The products of this mill are 50 mm square to 125mm square Billets and 140 to 240mm x 75/80 mm skelp slabs. Major Equipments: v Mill Train - Continuous morgan design with 8 strands v Up and Down Cut Shear: - For emergency purpose v Flying Shear - Shear a max. cross section of 130 square inch.

Reheating Furnace

Under the modernization scheme, the Blooming Mill including socking pits are supposed to be phased out. At present a new reheating furnace had been installed and running. Feed materials for reheating furnace are the blooms for Bloom Caster. Then Blooms are heated up in the furnace and directly fed to the Billet Mills.

SECTION MILL

Blooms from blooming mill are taken and rolled in section mill to produce light and medium structural like joists, channels and Angles. The capacity of Section Mill is 0.212 million tone per annum. Material Flow Diagram:

Bloom Stock Bay Furnace 1 or 2 Pusher &

Roller Table

26 2 High Roughing Mill

2 X 24 3 High Intermediate

Mill

24 2 High Finishing Mill Hot Saws

Straightening Machine

Hot Banks

Hot Bed

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Process: Blooms coming from Bloom Stock Bay are first reheated in Reheating Furnace

upto a temperature of 1250 C. Then it goes to 26 2 High Roughing Mill strands through the roller table. After initial reduction in roughing mill the stocks are rolled in 24 3 High Intermediate Mill stands. Finally, bars leaving the intermediate mill, enters into the 24 2 High Finishing Mills stands by traveling along the roller tables. After this finishing work the bars are cut by hot saws and cooled on one of the three transfer banks. Finally the bars are stacked in the staking area prior to straightening. Before dispatch, the bars are inspected, tested for chemical analysis and straightened by the straightening machines. Products: Joists 200 x 100mm, 175 x 85mm, 150 x 75mm, 116 x 100mm Channels 200 x 75mm, 175 x 75mm, 150 x 75mm, 125 x 65mm Angles 150 x 150mm, 130 x 130mm, 110 x 110mm, 100 x 100mm Major Equipments: v Reheating Furnace - 2 continuous end charge end discharge type. v Roughing Mill stands - Rolls of 26 diameter two-high reversing, closed top type. v Intermediate Mill Stands - 2 stands of 24 diameter three-high non reversing

open top housing type. v Finishing Mill Stands - 24 diameter two-high non-reversing, open top housing

type. v Finishing End - 2 hot saws. v Straightening Machine - 3 cold straightening machines.

SKELP MILL

Skelp Mill was not there at the initial phase of Durgapur Steel Plant. It came up during the expansion of plant to 1.6MTPA in late 60s. Skelp is a narrow section mostly used for the pipes and tubes manufacturing. The annual capacity of this mill is 0.25 million tone per annum. Material Flow Diagram: Process:

Looping Through

Rolled Slabs from Billet Mill Furnace Feed by Ram Charger

Pendulum Shear

Roughing Mill

6 x 2 High 16 E1-H1-H2-H3-E2-

H4-H5-E3-H6

Cobble Shear

Finishing Mill

5 x 2 High 13 H7-H8-H9-H10-H11

Apron Conveyor

Vertical Coiler

Coil Conveyor

Strapping Machine

Finished Products H - Horizontal strands, E - Vertical edge

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Skelp mill receives slabs from billet mill by rail transfer bogies. The slabs are taken on to charging table from the bogie. The slabs are fed to a reheating furnace by a Ram charger. The furnace is of side charge and side discharging type. The furnace is fired by a mixture of coke oven and Blast Furnace gas in a ratio of 1:1.

The furnace has a heating capacity of 60T/Hr. The slabs are sent to the mill

section, which consists of 11 horizontal strands and 3 vertical strands. These are arranged as shown below:

E1-H1-H2-H3-H4-H5-E3-H6-COBBLE SHEAR-LOOPING TROUGH-H7-H8-H9-H10-H11.

Where H refers to horizontal strands and E refers to vertical edge. The roughing mill constitutes strands from H1 to H6 while H7 to H 11 constitute the finishing mill. After rolling, the Skelp or strip is coiled and the coil is dispatched to customers. Products: Steel Strip and Skelp from 147 to 252 mm in width and 2.5 to 4.5 mm thick.

MERCHANT MILL

Merchant Mill takes billets of size 100 mm x 100 mm from CCP and produces plain round bars and ribbed TMT bars of various diameters. The capacity of Merchant Mill is 0.28 million tone per annum of plain round and thermo mechanically treated (TMT) ribbed bars of dia. 12, 14, 16, 18, 20, 22, 24 and 28 mm.

Material Flow Diagram: Process:

Billets from CCP are fed to the side charging & discharging type reheating furnace through furnace bed and ram charger. After reheating of it is delivered to the pinch roll and then to Roughing, Intermediate and Finishing mills stands

Reheating Furnace Billets

Thru Ram Charger

Up Down Cut Pendulam Shear

Intermediate Mill

Roughing Mill

FinishingMill

Thermax Process

Automatic Bundling / Binding Machine

Despatch Area

Cooling Bed

Rotary Shear

Rotary Shear

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consecutively. Roughing mill consists of 7 stands, Intermediate consists of four and the Finishing mill consists of 2 stands. In between 7th & 8th stand a crop cum cobble shear is placed, which is used for cutting the front end of each bar. After this the finished products are passed thru three Thermax carriages where TMT bars produced. tempered by intense cooling. Finally rotary shear cuts the rods into required length to accommodate them at cooling bed. After cooling the bars are cut by the Bar Shear and sent to automatic bundling / binding machine, where bars are packed and bound into neat bundles and sent to the dispatch bay. Major Equipments: v Charging Bed v Reheating furnaces - Two zone type arranged for charging and discharging v Pendulum shear - To cut the front end of billets v Mills - Continuous morgan design with 4 repeaters consists of 13 horizontal

stands (Roughing stands 1-7, Intermediate stands 8-11, Finishing stands 12-13)

v Snap Shear two nos. v Crop cum cobble shear - used for cutting the rolled stock in case cobble is formed. v Thermax carriage - 3 in numbers, Spray water at high pressure on the rolled bars. v Rotary shear & Bar Shear - To cut rods into predetermined lengths. v Automatic Binding / Bundling Machines - packs and binds the bars into neat

bundles. v Cooling Bed.

WHEEL & AXLE PLANT

Wheel and Axle plant is a pride unit of Durgapur Steel Plant. The main customer of wheel sets is Indian Railways. This was commissioned in 1962 with a capacity to produce 45000 wheels per year and subsequently raised to 80000 wheels per year. Wheels are produced by pressing and rolling while axles are produced by forging. Subsequently both are heat treated and machined. For the ease of production, wheel manufacturing section and axle manufacturing sections are located into two different bays. Set wheels and axles are finally meet in assembly section.

The present capacity is as follows:

Wheels: 40000 tonnes / annum Axles: 16000 tonnes / annum

Input: 12 sided Fluted Ingot of diameter 16 & 14 for wheels and Sqare blooms from Blooming Mill for axles.

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Material Flow Diagram:

Process:

Wheel making:

The 12 sided fluted ingots are inspected and cut into numbers of blocks. After physical inspection, blocks are heated in rotary hearth furnace for 6-8 hours to a temperature of 1300 C. The heated cheeses are descaled and fed to 63/12 MN Press for forging & punching. After this, wheel blanks are heated in batch type reheating furnace to 1150 C. The wheel is then rolled in a computerized wheel mill, where wheels achieve profile & dimension.

After rolling, the wheels are fed to a 20MN Dishing press, where the web profile is achieved. The wheel is then feed to a marking press of 3MN where sl. No., year and cast no. are stamped on the back rim. The wheel is then subjected to heat treatment which includes quenching and tempering to give hard rim and tough core. This prevents high internal stress during cooling and prevents warping of wheels. Next

Band Saw Block Heating Furnace 63/12MN

Press / Punch Reheating Furnace

Wheel Mill 20MN Dish Press Stamping

Press

Heat Treatment

Testing of Black Wheels

CNC Machining

Cold Stamping

Ultrasonic & OtherTesting

Dimensional Inspection

Axle Machining

Assembly

Forging Hammer

Heat Treatment Furnace

Heating Furnace

Inspection W&A Despatch

Wheel Ingot

Square Blooms

Ultrasonic & OtherTesting

Inspection Loose Axle

Loose Wheel

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comes the machining part, where rim face, boss face, rim blending, condemning glove, chucking glove are machined by means of CNC machines. Finally, the wheels are subjected to various tests such as Ultrasonic Test, Magnetic particle Test and BHN which are RITES certified. Axle making:

Square bloom made of killed steel is the raw material for axle. These blooms are heated for 6-8 hours in continuous pusher type furnaces after inspection. Blooms are forged in a 7 tonnes hand operated axle forging hammer. The process takes around 9-10 minutes and the finishing temperature is 850 C. The axles are then subjected to heat treatment. After heat treatment, axle is straightened in 150 ton horizontal straightening press. Then the axles are allowed to cool down in normal conditions.

Axle ends are sawed and are rough turned, then finish turned. Ultrasonic test is performed for checking physical soundness of every axle. The axles are inspected for dimensional accuracy at every stage of the process and for surface & diameter defects after completion.

Finally set wheels and axles go to assembly section. After assembly the set is checked for track gauge and after inspection it is despatched .

MAJOR SERVICES DEPARTMENTS Central Engineering Maintenance

The main function of this department is to manufacturing & reclamation of mechanical spares as per need of the plant. There are six sections in CEM:

1. Planning and Progress 2. Structural shop 3. Forging shop 4. Machine shop 5. Fitting shop 6. Tool room

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The main equipments in CEM are:

v Horizontal Boring machine v Vertical Boring machine v Gear Hobbing machine v Plano-Milling machine v Surface Grinding machine v CNC Profile cutting machine v Plate Bending machine v Shearing machine v M I G Welding v Submerged Arc Welding v Forging Hammer v Heat Treatment Furnace v Horizontal press etc.

Foundry

DSP is having its own foundry, referred as captive foundry. The main products are:

v Ingot mould (8.5T) v Bottom Plate (3T) v False Plate

Casting of different small structures is also done here to cater the needs of different shops. Important equipments are:

1. Pneumatic Rammer 2. K.S. Drag barrels 3. Stripping plates 4. Mix-Mullers 5. Jolting machine 6. Stoves 7. Guide Pit 8. Cupola Furnace

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Electrical Repair Shop

In this department electrical motor, generator & electromagnet from different department are repaired. The main jobs in ERS are winding, overhauling, repair and testing of Electrical machines. Major Equipments are: v LT Motor testing facility v DC Motor testing facility v 3.3KV Motor tester v Heat Chamber v Stripping machine v Coil making machine v EOT Crane etc.

Energy Management Department

The major functions of Energy Management Department are v Gas distribution and control v Maintenance of gas pipelines & gas holder v Gas safety monitoring v Conservation of energy consumption

EMD supplies BF gas, CO gas and BOF gas to different consumers through pipeline network (16.5 km long approx.).

The CO gas network process is normally maintained around 350 MMWC and for BF gas it is 380 MMWC. These gas holder are connected with network to maintain network gas pressure. The BOF gas, generated intermittently is first stored in a gas holder and then pumped into BF gas network. These gases are used in different shops either separately or mixed in different proportion before boosting up the gas pressure through the booster fan.

So far as conservation of energy is concern, monitoring of combustion control of

different furnaces, boilers, soaking pit etc. are done by EMD on a regular basis.

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Environment Control Department

The ECD was constituted to meet the legal requirements, social demands and commitments made in the memorandum of settlements with National Joint Committee on Safety with respect to Environment.

Main functions:

v Compliance with provisions of various environmental legislations /

regulations which involves statutory monitoring of air, water & noise pollution in different areas of plant and township.

v Investigative monitoring of air, water & noise pollution from different sources in the plant.

v To advise for further need in improvement of pollution control systems in different departments.

v Study of different kinds of solid wates generated from plant, and their recycling, selling and dumping status

Traffic

Transportation of materials is an important activity in an integrated steel plant. The Traffic organization plays a vital role in smooth running of the different production units, which leads to profitability of the plant by optimizing the cost of transportation.

The Traffic Organization consists of following departments:

1. Traffic Operation 2. Permanent Way Engineering (PWE) 3. TXR/Rerailment 4. Loco Repair Shop (LRS)

Traffic Operations:

It is taking over of all incoming wagons with raw materials and handling over of empty & loaded wagons to Railway at Durgapur Steel exchange yard. It is also controlling movements of different materials within different section in production units. Commercial section looks after the commercial aspects with Railway like freight, indenting, allotment of rakes, weightment and shortage, claim of rebates etc.

PWE Department:

It takes up repair, maintenance & renewal of 230 km network of Railway track for smooth movement of locos & rolling stocks.

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TXR/Rerailment Department:

The TXR/Rerailment department carries out inspection of DSPs rolling stocks for their fitness to run, take up minor repair work in different sick lines, take up all rerailment activity of all derailed rolling stocks inside work premises.

It also does the brake-releasing activity of all incoming loads prior to the Tippling

at RMHP and Coal Tipplers.

Loco Repair Shop:

Loco Repair Shop maintain 39 nos of locomotives and 2 nos of 50T rail crane, 1 rail crane and 1 magnet crane.

Power Plant Main Objectives are: To provide COLD AIR BLAST to blast furnace. To provide HP/LP process steam to BF, COCC, SMS, Oxygen & Sinter Plant. Power generation to provide energy power requirement. HP steam at 32 Kg/cm2

LP steam at 12.5 Kg/cm2 The capacity of this plant (4X5W=20MW). It is also called as blower plant as its main aim is to generate steam. There are seven boilers each having capacity 60 TPH. Steam is generated at high pressure. Boiler No. 1, 2, 5, and 6 uses coal and (BF+CO) gas as fuel. Boiler no. 3, 4 and 7 are gas fired using (BF+CO) gas.

Power Management Department

Function : v To receive & distribute Power as per requirement of different units of the DSP,

ASP & Township. v To maintain all equipment related to Distribution Network. v To maintain the Cost of Power within Budget. v To Monitor Consumption of Power of different units. v To maintain illumination of road and areas inside the plant.

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Power Requirement :

Requirement of DSP & ASP is met by Power we purchase from DVC (Grid source) & NSPCL (Captive Unit). Power demand of DSP & ASP is as following.

DSP Average : 95 MW. Peak : 125 MVA. ASP Average : 30 MW. Peak : 65 MVA.

Source of Power : Grid :- DVC Contract Demand : 85 MVA. Captive :- 1. NSPCL - 2 x 60 MW (Thermal).

2. OPP - 4 x 5 MW (Thermal).

There is a SCADA system installed in MRS. It stand for supervisory control and data acquisition system. It act as an inter face between main receiving station and other distribution centers. In case of any power failure, it ensure that power supply in critical zones remain uninterrupted. There is Computerised Islanding scheme with load shedding package for isolation of NSPCL units from grid in case of any grid disturbance.

Plant Civil Engineering

The main functions of PCE is to repair and maintenance of plant roads, buildings, sheds, underground swerage system and overall upkeepment of the plant, department and maintenance of lawn & gardens by the side of the main road of Plant.Beside this paintings, repairs of plant structures are also done by this department.

Oxygen Plant

The main objectives of this department are: v To supply generate oxygen at 99.5% purity and 16 kg/cm2 pressure. It has

nine gaseous O2 storage vessels and two liquid oxygen storage tanks. The capacity of this plant is (2X350=700TPD).

v To supply N2 at a pressure of 8 kg/cm2 / 16 kg/cm2 at a purity of 200 PPM.

Products of this plant are: 1. Oxygen gas for BOF, CCP, BF, Rolling mills. 2. Liquid oxygen for oxygen cylinder refilling 3. N2 for BOF, CCP, BF, EMD. 4. Argon for BOF,CCP, VAD The distribution network is spread over 18 Km in the plant.

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Computer Managed Maintenance System

The function of this department is to achieve systematic approach to maintenance using CMMS package as a tool for reliable and effective maintenance information system. The objectives are: v To understand the maintenance practice of the plant v To develop computerized maintenance system. v Generation of reliable data bank

The maintenance system in DSP had a conventional practices by all the departments i.e. log book/ledger/cards etc. In order to come out of this syndrome a systematic approach towards maintenance supported by a reliable and effective system was established. With the introduction of CMMS the maintenance practices are getting more and more standardized.

Research & Control Laboratory

This department is responsible for maintaining the quality of product and develops new products to cater to the needs of customers with the ever changing demand. For this purpose periodic monitoring and controlling of the quality of input raw material, process and final products is required. Major activities of this department are:

1. Process control 2. Inspection 3. Analysis and testing 4. Research and development

To achieve these it has a main laboratory outside the plant and the other

laboratories are inside the plant. The laboratories inside the plant are at RMHP, BF, BOF, Coke Oven, Rolling mill, Wheel & Axle plant etc. The main lab is well equipped with chemical, metallurgical and other facilities.

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Computer & Information Technology Department

C&IT Department is the centre nodal agency for IT activity of DSP. The main feature of C&IT department is as follows:

v Production, Planning & control. v Process Control, v Finance & Accounting System v Maintenance Management v Salary & Payment System v Maintenance of Network v Database Administration

Most of the production process & services are connected in the network and data

can be available on-line for better monitoring of the above activities. Presently ERP is also under stage of implementation for the following modules: v Finance & Accounting v Sales & Distribution v Quality v Maintenance v Material v Production & Planning

The go-line is fixed as 31-03-2009.

Human Resource Department

Centre for Human Resource Development is the nodal agency for facilitating competency assessment and training need identification of employees. Various kinds of training programmes are conducted throughout the year. The main areas of training are:

1. New Entrants Training e.g. MT(T), SOT, JOT and TA. 2. Competence Enhancement

a. Managements & Supervisory Development programmes b. Electrical, Electronics and PLC Training c. Hydraulics and Pneumatics Training d. Computer Training e. Basic Engineering Skill at Workshop f. Unit Training at Shop Floor etc.

3. Specific Areas : Safety, Health and Environment Training. 4. External Training : At suppliers Workshop in India / abroad. 5. Others : Workshops, RajBhasha etc.

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Town Administration & Services

Durgapur Steel Plant has a modern township spread over in 40 sq-km area. It has 3 zones namely A, B and C with 24141 houses of DSP and around 4900 houses of ASP. DSP Township has following main features: v Stadium 2 nos (DSP -1, ASP 1) v Community Centres 6 nos v Schools / Colleges 6 High Schools, 2 Primary schools and a large number of

Private schools / colleges v Sector Markets 7 nos v Club 5 nos v Parks 3 nos v Guest Houses 3 nos v Swimming Pool 3 nos v Petrol Pump 3 nos v Road Networks 81 km main road and 230 km street roads v Hospitals 1 Main Hospital and 5 Health Centres

Medical & Health Services

DSP has modern 640-bed General Hospital with 5 Health Centre and 1 Occupational Health Service Unit. The Bed Occupancy rate of this hospital is 70%. New facilities in DSP Main Hospital: v New ward block housing 4 sets of Dialysis units. v New centralized dental clinic v New eye bank v New state-of-the-art Burn Care Unit v 9 bedside cardiac monitors with central monitor,

Difibrillator and ventilator in ICU v Revamped OPD v Binocular microscope, Coagulometer, Tissue Processor, Terbidometer, Flame

Photometer in Pathology Department v Phaco emulsification unit in the Eye Department v DCR with help of nasal endoscope in ENT, a first in SAIL Hospitals v New Audiology room and new instruments Micro Debridor and Sinus shavar,

Fees set etc in ENT

Our DSP Main Hospital also contains one Neo_natal Care Unit and CT Scan to take care employees of the plant and their family members.

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Corporate Social Responsibilities

Durgapur Steel Plant has taken CSR as a its focused area to create a meaningful difference in the life of the people residing in and around DSP township. The main areas of activities are:

1. Developing villages 2. Educating masses 3. Securing Healthcare 4. Aiding Physically Challenged 5. Generating Employment 6. Promoting Sports 7. Galvanizing Social Change

Sample Questions: 1. Following is not a product of DSP

A. TMT Bar, B. Skelp, C. Wheel, D. Rail

2. No. of Blast Furnaces in DSP A. 1, B. 6, C. 4, D. 9 3. The size of BF Grade Coke is A. 25mm 50mm, B. 15mm 60mm, C. 20mm 40mm, D. 20mm 80mm 4. DSP has the following nos of coke oven battery presently working A. 3 and , B. 5 and , C. 4 and ,, 4. 6 and and . 5. Presently percentage of Sinter in Blast Furnace charge is around A. 70 75%, B. 80 90%, C. 60 70%, D. 90 - 100%. 6. DSP Township has following number of Health Centres A. 4, B. 5, C. 2, D. 10. 7. First Ingot was cast at DSP on dated A. 24-04-1960, B. 24-05-1959, C. 24-05-1961, D. 24-05-1958. 8. The present Hot Metal capacity of DSP is approximately A. 1.5 MT, B. 2 MT, C. 2.5 MT, D. 3 MT

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32

DURGAPUR STEEL PLANT (Plant Specific Overview)

Contents

Page 1. Introduction 1 2. Historical background 1 3. General Overview of DSP 2

A. Major Product Profile 2 B. Major Highlights 3 C. Process Flow diagram 4

4. Major Production Departments A. Raw Material Handling Plant 5 B. Coke Oven & Coal Chemicals 6 C. Sinter Plant 9 D. Blast Furnace Complex 11 E. SMS Complex 13

i. Basic Oxygen Furnace 13 ii. Continuous Casting 13

iii. New Lime Calcination Plant 14 F. Blooming & Billet Mill 14 G. Section Mill 16 H. Skelp Mill 17 I. Merchant Mill 18 J. Wheel & Axle Plant 19

5. Major Services Departments A. Central Engineering Maintenance 21 B. Foundry 22 C. Electrical Repair Shop 23 D. Energy Management Department 23 E. Environment Control Department 24 F. Traffic 24 G. Power Plant 25 H. Power Management Department 25 I. Plant Civil Engineering 26 J. Oxygen Plant 26 K. Computer Managed Maintenance System 27 L. Research & Control Laboratory 27 M. Computer & Information Technology Department 28 N. Human Resource Department 28 O. Town Administration & Services 29 P. Medical & Health Services 29 Q. Corporate Social Responsibilities 30

6. Sample Questions 30

33

A Manual On

For

Junior Officer Scheme