plan induction report

8/22/2019 Plan Induction Report

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ABOUT SAIL

Steel Authority of India Limited (SAIL) is the leading steel-making company in India. It is a fully

integrated iron and steel maker, producing both basic and special steels for domestic construction,

engineering, power, railway, automotive and defence industries and for sale in export markets.

SAIL manufactures and sells a broad range of steel products, including hot and cold rolled sheets

and coils, galvanized sheets, electrical sheets, structural, railway products, plates, bars and rods,

stainless steel and other alloy steels. SAIL produces iron and steel at five integrated plants and

three special steel plants, located principally in the eastern and central regions of India and situated

close to domestic sources of raw materials, including the Company's iron ore, limestone and

dolomite mines.SAIL's wide range of long and flat steel products is much in demand in the

domestic as well as the international market. This vital responsibility is carried out by SAIL's own

Central Marketing Organization (CMO) and the International Trade Division. CMO encompasses a

wide network of 38 branch offices and 47 stockyards located in major cities and towns throughout

India.

With technical and managerial expertise and know-how in steel making gained over four decades,

SAIL's Consultancy Division (SAILCON) at New Delhi offers services and consultancy to clients

world-wide.

SAIL has a well-equipped Research and Development Centre for Iron and Steel (RDCIS) at Ranchi

which helps to produce quality steel and develop new technologies for the steel industry. Besides,

SAIL has its own in-house Centre for Engineering and Technology (CET), Management Training

Institute (MTI) and Safety Organisation at Ranchi. Our captive mines are under the control of the

Raw Materials Division in Calcutta. The Environment Management Division and Growth Division

of SAIL operate from their headquarters in Calcutta. Almost all our plants and major units are ISO

Certified.

Integrated Steel Plants

Bhilai Steel Plant (BSP) in Chhattisgarh

Durgapur Steel Plant (DSP) in West Bengal

Rourkela Steel Plant (RSP) in Orissa

Bokaro Steel Plant (BSL) in Jharkhand

IISCO Steel Plant (ISP) in West Bengal

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LAYOUT OF BOKARO STEEL PLANT

The location of the steel plant at Bokaro was envisaged as a coal based plant with other raw

materials being far away. The captive Iron Ore Mines of Bokaro are located at Kiriburu which is

near to Rourkela Steel Plant. It was Planned that Rail Wagons taking coal to Rourkela will be used

after unloading, to reload with iron ore meant for Bokaro .This saves a lot of Idle capacity of

railway wagons and economically benefiting S.E. Railway as a close circuit movement of coal.

This plant even at conception stage was planned to be a big plant. Therefore, layout plan has space

free for such an additional capacity even beyond 4 Mt per annum, say 5 or 5.5 Mt per annum. It

was taken up for execution in two stages 1.7 Mt/year in 1 st stage and 4 Mt/year in 2nd stage.

Bokaro Steel Plant is located in south Bihar along the Ranchi Dhanbad Highway. It is on the

confluence of river Damodar and River Ganga. These two rivers form the boundaries in North and

East with western Boundary being S.E. Railway track of Muri-Chandrapura and Ranchi- Dhanbad

highway being boundary in the south. Ranchi, Bokaro Jamshedpur forms the three points of a

triangle each about 145 Km. equidistant from each other. Dhanbad is a Rail Junction point about 50

Km away, which is a Delhi-Calcutta chord line of Eastern Railways. This is the only steel Plant

which is on the Branchline of railway and not on the main line.

Bokaro has a good raw material base. Since it is coal based all sources of coal washeries are within

35 to 40 km from the plant. Iron Ore is from Kiriburu which is about 385 km away in south;

Limestone and Dolomite from Bhawanathpur about 415 km in west and SMS Grade Stone from

kuteshwar near Kathi about 600 Km west. The average travel distance of Raw Material for 1.7Mt

stage is about 250 Km and for 4Mt stage 305 Km. Average Tone Km of Ingot Steel is about1600Km for 1st stage and 1234 Km for 2nd stage. As stated earlier layout of Bokaro falls in category

Oblique Sequential and has single rail track entry and exit to 2 exchange yards of S.E. Railway

near Tupkadi Rail station. Their is a built in provision for expansion of individual units in their

existing series without interfering with other units.

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In Bokaro steel plant 48% of the internal traffic is by rail and Railways constructed a large

marshalling yard with complete marshalling facilities on modern lines on a stretch of 8Km long.

The amount of inter shop transportation by mechanical transport facilities of belt and chain types

will be 31.6MT for the 4 MT stage (18MT for the 1.7MT stage.).The total length of the belt

conveyor alone is 18Km in 1st

stage and 32Km in 2nd

stage. More than 300 equipments are used for

internal transportation and unloading. This plant has an additional advantage with extensive repair

and workshop facilities for repair, maintenance and manufacture of spare parts with a huge

structural shop and m/c cum maintenance shop, large Iron Steel and Non-Ferrous foundries

attached forge shop and wood working and building maintenance shop. Equally big is the Electrical

and Instrumentation repair shop.

Since the design itself provided by the plant is of 4MT capacity as provision of technologically

pipelines, cables, rail tracks and road has to be maid in the initial 1.7Mt stage itself. Thoughconstruction cost at the 1st stage is high, it has definite advantage for 4MT expansion. Only the

construction jobs of new units were carried out without interfering the first stage plant that was

working at the time of expansion.

Steel production technology

Molten

steel

Ingot

casting

Continuous

casting

Ingots

Primary

rolling

Billets

Blooms

Slabs

Bars, rods, rounds

Rails, structurals

HR coils

& strips

Plates

Pipes

CR sheets

& strips

Coated

sheets

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The plant area is 1028 hectares (16876.83 acres) with two huge water reservoir at the East and

West side of the plant. The water source of the plant is from a dam across the Damodar River at

Tenughat about 45 KM away towards West. The drinking water for the township during the initial

stage is supplied by an earthen dam across the river Ganga that is augmented with additional water

from Damodar from the plant reservoir. The electric power for Bokaro plant has come from

Chandrapura Thermal Power Station of the DVC grid. The power plant is on the other side of the

river Damodar and for the 1st stage 140MW of power and 359 MW taken from 2nd stage from this

grid. The residential township is located on the eastern side of the plant area and occupies

10,000acres with 40,000permanent houses, 1100 semi permanent houses and over 500 hutments.

The wind direction for the last 50years was considered at the design stage itself and township was

built at the eastern side of the plant right at the Sangam of the two rivers Ganga and Damodar:so

the dust and the air pollution of the plant does not go to the township. In spite of this it is veryunfortunate that the smoke emitted from the Chandrapura Thermal Power Plant of the DVC emits

copious dust towards the township area thereby nullifying the designers concept of pollution free

township.

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RAW MATERIAL HANDLING PLANT (RMHP)

Introduction:

Raw material handling plant is one of the most important units of integrated steel plant like BSL.

The progress of an industry is not indicated merely by how much it produces, but how efficiently it

produces. Productivity is an indication of efficiency with which resources are converted into goods

or services while output is production. Major input for steel plant comes from mines to RMHP. So

for efficient production it is necessary to establish this plant at proper site in an integrated steel

plant, so that all plants can easily get raw materials from this plant.

Basic Functions:

Release of different raw material wagons from different mines by wagon tippler.

General Overview of Iron Ore Flow

IRON

ORE

Drilling & Blasting

Truck despatch Crushing Screening

-10mm 10mm to 50mmFines Lump

Rail

Despatch

Blast

Furnace

OB

Coal Flux

Hot Metal

Steel

Melting

Shop

Rolling

Mills

STEEL PLANT

MINES

Flux

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To do the blending by doing homogenous pile of raw material with the help of

stacker and reclaimer.

Supply of raw materials to different customer departments as per their

requirement.

Keep a buffer stock of raw materials in order to take care of irregularities of

supply.

100%screening of high grade limestone and dolomite for RMHP.

100%screening of iron ore lump for BF

Customer Departments:

Refractory material Plant

Sinter plant

Blast Furnace

Sections:

The department is divided into two sections:

RMS-1

RMS-2

Sources of raw material:

Name of Raw material Souces

Iron Ore Lump Kiriburu,Meghatuburu

Iron ore fines Kiriburu,Meghatuburu

Limestone for Sinter Plant Bhawnathpur,kuteshwar

Dolomite for sinter Plant Bhawnathpur,Birmitrapur,Sonakhan,

Rajganjpur

Limestone for RMHP Jaisalmer

Dolometric Limestone Nanwara

Main Equipments

Equipments Nos Make Capacity

Wagon Tippler 4 HEC 20 Wagon/HR

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Stackers 6 TRF 1200T/HR

1 WMI 1200T/HR

Reclaimers 5 ELECON 1000T/HR

Bucket wheel 1 MUKUND 500T/HR

Reclaimer IRON LTD.

Limestone Screening 1 HEC 500T/HR

Plant

Limestone ore 1 IC INDIA 500T/HR

Screening Plant LTD.

Important Equipments:

Stacker:

Function of a stacker:A stacker is used to stack the material on bed layer in a length of about 240

mts. The full pile of material forms, after about 250-350 layers of material, a homogeneous pile of

raw mterial to achieve blending.

Working Systems:

1. Traverse Drive system

2. Boom and Boom Conveyor System3. Boom Hoist and Lowering System

4. Receiving Chute and proper System

5. Operating and Electrical Switch Board Cabin

6. Various Interlocks and Emergency Switch

Barrel Type Reclaimer (Blender)

The purpose of the reclaimer is to reclaim from the fully built-up stockpile and discharge the

material on a reclaiming conveyor. Material can be reclaimed from one end of the pile, cross

section wise. This process achieves blending if the stockpile is built up layer wise during formation.

The machine ios centrally controlled by the operators cabin. During reclaiming operations, the

machine travels in the direction of the stockpile at a slow and constant speed. The harrow, which is

built in front of the machine, has a reciprocating movement which causes the material to stock

down the face of the stock pile where it is reclaimed in the barrel buckets arranged on the

circumference of the barrel. From here, the material is discharged out of the buckets on to a belt

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conveyor inside the barrel, which transfers it to the reclaiming conveyor running along the length of

the conveyor.

Bucket Wheel Reclaimer:

The reclaimer is the type of rotary wheel type, with a traveling gallery, a hinged boom mounted on

a rotating structure for slewing. An operators cabin is vertically suspended and is located at the

end of the boom. The boom is 32 mts long and can be lifted up and down to reclaim raw materials.

The machine travels along rails, which straddle the yard conveyor. The machine is capable of

reclaiming at the rate of 500 ton per hour. Slewing of the boom conveyor assists reclaiming

operations and permits the reclaiming of longitudinal piles on both the sides of the reclaimer track.During reclaiming operations, the rotating bucket wheel scoop up the raw materials and discharges

them to the yard conveyor via boom conveyor and central chute.

Wagon Tippler:

It consists of a rotor having three rotor ring. Each ring is made up of two rigidly coupled

symmetrical structure members. It works on tilting mechanism. It is used to empty the wagon full

of raw materials in to the hoppers below.

Iron Lump Ore Screen Plant:

Its function is to screen out 10 mm Size of iron lump ore and send to sinter plant and to screen out

+10 mm to -40 mm Size of iron ore lump And send to Blast Furnace. In this system, iron Ore Lump

is send to conveyors. This conveyor feeds material to the screen. After screening the 10 mm size

Iron Ore goes to the sintering plant bins through conveyors. Required Size of Lumps goes to the

Blast Furnace through conveyors.

Tram Car Pusher

It is an electrically operated pusher car. Its function is to haul the railway Wagons to the Wagon

Tippler. It works only on one track preceding the tippler. It has got three operating speeds of :

0.25 mts per second

0.5 mts per second and

1.0 mts per second.

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It has a capacity of pushing 28/56 wagons of 60 tones material on railway track on horizontal

strench and straight line.

Transfer Car Operation:

The stacker can be transferred from one KPC to another KPC and the reclaimers from one bed to

another with the help of this car. For transferring the reclaimer or stackers: transfer car is to be

placed in position in such a way that the rails of the stacker /reclaimer track are aligned with

corresponding rails of the transfer car with a tolerance of 1/16 inches. Necessary packing is to be

put below the transfer car rails and Wheels.

Conveyor AND their Control:

Rubber belt conveyor of different sizes is used in this plant are used for conveying material from

place to place. Total length of the conveyor is 42 kilometers. All the stacking and reclaiming

conveyors can be operated in three ways.

The names are:

1. Local + Individual

2. Local + Sequence and

3. Master Control Desk.

Bed Preparation Plan:

Name of Raw Materials No. of Beds Capacity

Iron Ore Lump 4 40000T per Bed

Iron ore fines 6 50000T per BedFlux LS:DL=45:55 4 30000T per Bed

LS SMS(JSM) 1 10000T per Bed

Dolomite-LS 3 10000T per Bed

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COKE OVEN AND BY-PRODUCT PLANT

Introduction:

Coke is the most important fuel used in metallurgical industry. Coal includes different classes of

fuel (solid) that occurs on the crust of earth. The entire resources of coal can be classified into two

groups:

Coking Coal

Non Coking coal

If the coal when heated in bright red in the absence if air softens swells and eventually

solidifies in to a more of less solid coke, it is classified as coking or caking coal. All coking coals

are caking in nature but all the caking coals are not may be coking. Coking coal on carbonization

gives metallurgical or blast furnace coke. Non coking coals fail to produce blast furnace coke on

carbonization. The moisture, ash , sulphur content in the coal play a vital role in deciding the

quality of coke that are produced in the coke oven area. They should be on lower side.

Sections: There are four sections in coke oven and By-Product plant

Coal handling plant

Coke Oven Batteries

Coke Sorting plant

By-Product plant

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Coal Handling Plant:

The coal handling plant receives coal from the following sources:

Primary coking coal( found in Jharia):Dugda, Moonidih

Medium Coking coal: Kargali , Kathara, Mahuda

Imported Coal:Imported coal from Australia and New Zealand Through Haldia,

Paradeep and Vizag Port.

The coking coal blend which is charged into coke oven batteries consist of 35% prime

coking coal,25% medium coking coal and 40% imported coaking coal. Due to the low ash content

of imported coking coal as high as 50% imported is being used now a days.

Coke Oven Battery:

The process of coke making consists of the destructive distillation of coke in the absence of air in

the coke oven batteries. Coke oven battery is called because coke making is our ultimate purpose

which is fulfilled by feeding coke into the ovens in a controlled manner and those ovens when

placed in a series form a battery e.m.f.

COAL HANDLING

PLANT

COKE OVEN BATTERIES

N G

BENZENE

N G

TOLUENE

XYLENE

H P

NAPH

THAL

ENE

SOFT

PITCH

HARD

PITCH

EXTA

HARDPITCH

P

C

M

CLEA

N C O

GAS

AMM

.

SULP.

CRUDE

BENZOL

CRUDE TAR

BY PRODUCT PLANT

BREEZE

COKE

(0-15)mm

PEARL

COKE

(15-

25)mm

B F

COKE

(25-

80)

mm

COKE SORTING

PLANT

FLOW DIAGRAM

BLAST

FURNACE

SINTER

PLANT

COAL

COKECOKE

OVEN

GAS

CONSUMERS

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In coke making, coal is heated in a closed in a closed chamber, thereby driving out

the volatile components present in coal and leaving behind a solid coherency mass called coke.

This phenomenon is called carbonization of coal .The carbonization of coal is carried out at

different temperature depending on the type of coke we need. At Bokaro carbonization temperature

usually kept above 900o

C i.e. high temperature carbonization is done.

Design Features of BSL Coke Ovens battery:

No. of Batteries=08

No. of ovens in each battery=05

Width of coking chamber(p/s)=.39m

(c/s)=.43m

Length of coking chamber=15.04m

Useful volume of chamber=27.3m3

Coke pushing furnace=9-2series

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A typical composition of coke from SAIL plant is:

Fixed carbon=77%

Ash content=22-24%

Volatile matters=


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Ammonia Recovery Plant:

Ammonia is present in the coke oven gas to the tune of 6-8gm/Nm3 and is recovered by treating

with dilute sulphuric acid employing saturation oil spray absorber-crystallizer process.

Crude Benzol Recovery plant:

Benzol in coke oven gas is recovered by adsorption or absorption or freezing (compression and

cooling) methods. This method of absorption with wash oil has predominant application in the

industry.

Two types of wash oil which are commonly used:

Solar Oil

Coal Tar wash oil

By products yields are:

Benzene

Toluene

Xylene

Naphtha

Major on going projects in BSL:

Augmentation of coal storage facility

35 additional silos

Extension of pre & post tippling lines to accommodate full rake

2 new wagon pushers capable of handling full rake

Enhancement of unloading track from 600 T / hr to 900 T / hr

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SINTER PLANT

Sinter:

Sinter is a process agglomeration of mineral fines formed after incipient fusion

Sintering:

Sintering thus a process of preparing sinter in which a high temperature is maintained such that the

material (mineral/ores fines) undergoes incipient fusion due to the burning of solid fuels present

within itself.

The incipient fusion imparts better porosity and thus good reactivity. Sintering plant as such is

required for two basic purposes:

Water management

Advantageous properties of sinter

Sintering as a process uses all the wastes generated in the mines site, handling and the mill zone. So

it is a good source of waste management. Apart from this sinter has lots of advantages than lumps

to use as a burden material in B.F. Nowadays 70% of the blast furnace burden is sinter.

Raw materials used for sintering:

Ore Fines

Flux(Limestone Dolomite)

Coke

Additives:

Flue dust(from blast furnace)

Mill scale(from slabbing mill and HSM)

LD slag from SMS

Calcined Dolo(from RMHP)

Lime dust(from RMHP)

Sinter return(own generation)

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Different sections of sinter plant:

Raw Material section

Proportioning section and stock bins

Machine Building

Raw Material Section:

It deals with raw materials coming from various sources and process it to the needs of sintering

plant. This section receives coke from coke oven and stores int its fuel storage yard. The coke

return from B.F is also kept here for use. This coke is then charged to four roll crushers which

discharges coke of -3mm size. Conveyor belt no PM-8(called RM-8 due to Russian alphabet)

carries in the proportioning section.

No. of coke crusher=8

Capacity=16T/Hr

Type=4 roll crusher

2 upper rolls for primary crushing=-6mm

2 lower rolls for secondary crushing=-3mm

Coke feed size=-12mm

The speed of lower rolls is slightly greater than the upper rolls to avoid choking or clogging. The

flux required for sintering comes from RMHP. It is crushed to hammer crushers to get 90%

undersize of -3mm.The oversize is again recycled.

No. of hammer crushers = 05

Stock Bins and proportioning section:

The function of the stock bin and proportioning section is to receive materials, prepare

the raw material and store it in the bins. There are 23 bins /machine. The capacity of the bins for

various raw materials is follows:

Iron ore fines=3600T

Limestone Fines=3000T

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Coke Breeze=1000T

Mill Scale and Flue dust=6000T

Hot and Cold sinter=1800T

Waste Bin section:

This section receives waste material from different departments like flue dust, from blast furnace,

mill scale from slabbing mill, limestone from refractory material plant. Then this is proportioning

and sent to the stock bins.

Machine Building section:

The m/c building section has three machines with sinter area of 252m 2 /m/c.6.2MT of sinter per

year is produced with a productivity of 1.2T/ m 2/hr.Ther are 180 pallets per machine. A bed of

25mm is made with bed material(sinter return),then first layer is of 300mm and top layer is of

300mm with a extra coke of 1% is made up to 150mm.

The ignition hood has a primary and secondary hearth In the primary hearth mixed gas

is burnt from slit burners creating a temperature of about 1200oC.In the 2nd hearth coke oven gas are

burnt creating a temperature of 900 oC. The pallets then move only 26 vacuum chambers. The burn

through point i.e. sintering should be achieved at 23 rd vacuum chamber. After the hot screening the

sinter pass through straight line cooler with 6 blowers blowing 6X22000m 3/hr of air to cool the

sinter from 300oC to below 1000 o C

Cold sinter return from machine building section is -8mm,8-12mm sinter is used as bed material

and +12mm sinter is used in B.F. The basicity of super fluxed sinter is 1.8 to 2.8.

Nearly 52KWH of power is consumed per tone of Gross section.

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BLAST FURNACE

Introduction:

Blast Furnace can be termed as the core metallurgical reactor for the production of

Hot Metal. It is a counter-current heat and mass exchanging reactor in which there is a continuous

transfer of mass(O2, C,H2 ) and thermal energy between descending burden materials and ascending

gases generated at the tuyer level.

Inputs:

Iron ore lump

Sinter

Metallurgical Coke(+25mm to -80mm)

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Limestone

Manganese/Quartize(Additives)

Nut Coke/Special Coke(in case of CDI)

Outputs:

Hot Metal

BF Gas(used as fuel)

Gangue Material in the form of slag.

Blast furnace is a counter-current heat exchanger and a chemical reactor in which Iron bearing

materials, coke and flux are charged from the top of the furnace and hot air blown through tuyeresat the bottom. Combustion of coke takes place in front of tuyeres generating heat and reducing gas.

C + O2= CO2

CO2 + C= 2CO

(Solution loss reaction)

Remaining unreduced iron oxide (FeO) reaches the lower part of the furnace (high temperature

zone) and is reduced by carbon of coke (Direct Reduction reaction) at ~12000oC.

2FeO + C= Fe + CO2 (Endothermic Reaction)

Metalloids reduction endothermic also takes place in this lower part of the Furnace.

SiO2 + 2C= Si + 2CO

MnO + C= MnO + CO

P2O5 + 5C = 2P + 5CO

Sections and Functions

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INNER STATE & AERODYNAMICS IN BLAST FURNACE

DEAD MAN

COKE

LUMPY ZONE

(STACK)

COHESIVE ZONE

(LOWER STACK

& BOSH)

ACTIVE COKEZONE

(BOSH+HEARTH)

MECHANICAL

SUPPORT TOBURDEN

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Ferrous Burden

Tuyere Gas

10000C

Isotherms

12000C

Isotherms

SLAG&COKE

METAL&COKE

COKE SLIT

RACEWAY-2000OC

FUSED SLAG

& Fe

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Raw material charging section:

Receives raw material from RMHP, Coke Ovens, Sinter Plant and then supplies to the furnace top

by means of Skip car.

Typical size ranges of raw materials for achieving better performance are:

Coke- 25-80mm (with +80mm


21/47

Stack

Throat

Refractory Lining:

Hearth : Micro-Pore carbon Blocks

Tap Hole : Mullite Blocks/Bricks

Tuyer and

Bosch Zone : Fire clay

Belly& Stack : High density hard burnt fire clay brick

Furnace Cooling:

Bottom Hearth : Air Cooled

Hearth, tuyer

Zone, Bosch&

Belly : Stave Plate Coolers

Stack : Peripheral Stave Tooth Coolers

Total No. of Stave Coolers : 512

No. of Rows : 12

Number of Stave Coolers/row : 40(minimum)Stave Coolers are double walled plate type coolers having arrangement for Water Circulation.

Stoves:

Hot air blast is supplied through stoves which are maintained at 1350o C with the help of

combustion of mixed gas. The stoves have refractory lining of chrome magnetite from inside and

fire clay outside.

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Auxiliaries:

Pig Casting Machine:

HOT BLAST STOVES :

Flue

Gas CHECKERCHAMBER

COMBUSTION

CHAMBER

Hot Blast

ValveHot Air

Gas & Air

Burner Valve

DOME Of No.stoves : 4 / furnaceFull height of stoves: 45,200mmExternal of the : 9000mmCylindrical part

Thickness of the wall: 605mmDome thickness : 686mmSurface of heating 30,300 M2No. of checker holes 4,400 - 4,720

The combustion chamber is of half circle, half

elliptical shape with working section of: 4.28 M2

SCHEMATIC DIAGRAM

COLD AIR FROM TBS

Cold Blast Valve

HOT BLAST STOVES:

Hot Blast Main

STOVE1

STOVE2

STOVE3

STOVE4 10-12 ata

Steam

Cold Air from TBS

Pr.2.5-2.6 Kg/CM2 , Temp. 150-

190

O

C

Snort valve

BUSTLE MAIN

FURNACE

TUYERES

SCHEMATIC DIAGRAM ----- SUPPLY OF HOT BLAST IN THE FURNACE

Hot Air 1000OC

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There are 4 pig casting machine of two stands each having a capacity of 1700T/day of pig iron

metal which is poured into moulds which are water cooled and continuously mould. The cold pigs

produced are supplied to cold peak yard.

Laddle Repair shop:

Laddles are required for hot tapping and are repaired in ladle repair shop for defects like refractory

lining lugs etc.

Slag Pot Repair Shop:

Slags pots are of capacity 13.5m3 are prepared and minor repair are done.

Clay Mass shop:Tar bounded anhydrous clay mass is produced in this shop to close the tap hole of the furnace after

tapping is done.

Technical Data:

No. of BF=5

Volume of each furnace=2000 m3

Working Volume=1756 m3

Capacity of Furnace=2640TPD/furnace

No. of stoves per furnace=30,300 m2

Blast temperature=1100o C

Max. Blast Pressure=3.2Kg/cm2

Charging Scheme=BLT

Hot Metal Specification:

C=4-4.5%

Si=0.6-1.2%

Mn=0.6-1.2%

P=0.25%

S=0.05%

Coke Rate:

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Coke rate is the amount of coke required per ton of hot metal .It was 360Kg/THM for

95-96 and presently it is around 560Kg/THM.

Future Plans in Blast Furnace:

Upgradation of blast furnace no.2 in 2007-08 and of other furnaces in phased manner to

achieve 6.5 million tons of hot metal production by 2011 2012 as per corporate plan.

Cast house sgp in 4-furnace.

Coal dust injection (cdi) in bf-2 & 3.

Hydraulic mudgun & drilling machine in all the furnace (in 2 furnaces at present).

Improved designed stoves.

STEEL MELTING SHOP 1

Introduction:

Steel making is a process of removal of impurities like carbon, silicon, Mn, sulphur and phosphorus

from the hot metal by oxidation and formation of basic slag. For this the hot metal of BF is taken to

LD converter after mixing in the mixture. Pure oxygen is blown through water cooled lance to

removeimpurities by oxidation and steel is made .Purity of oxygen is used about (99.5%).

There are two Steel Melting shops, SMS-1and SMS-2.Three types are produced from these shops:

Killed Steel

Semi-Killed steel

Reamed Steel

Raw Materials:

Apart from the hot metal from the Blast Furnace the different raw material required for the

production of steelier:-

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Limestone

Dolomite

Aluminum

Ferro Alloys

SMS-1:

At BSL SMS-1 has 5 no. of LD Converters each of 100/130T capacity .The capacity of these shop

is 2.5MT/year.For oxygen blowing there are 2 water cooled lance. The oxygen pressure is 15-

20kg/cm2 .

VARIOUS SECTIONS

Mixer:

The mixer is of 1300T capacity and temperature is about 1310+10o C, it is operated. The functions

are:

o It makes the hot metal from 5 BF homogenous.

o It maintains the temperature.

o It acts as a buffer stock.

Converters:

This converts hot metal into steel following an exothermic reaction.Line, scrap and hot metal are

charged in a definite sequence and then oxygen lancing is done. The lime and other additions are

done through a slide gate system. Lime is added as a flux to maintain the basicity of the bath.

Basicity is defined as the ratio of Cao and SiO 2 and it is kept between 3 to 3.5.

Pit side:

Steel is tapped from this side into the teeming ladles (140T) and transfer to teeming bay after de-

oxidation.

Teeming Bay:

Steel is poured from teeming ladle into moulds (placed in mould train) by operating slide gate and

sent to stripper yard.

Stripper yard:

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The ready ingot is stripped here from the mould and is sent to the slabbing mill, where as mould is

sent back to the mould cleaning yard, where it is cleaned by water spray and coated with tar or

graphite.

Waste heat boiler:

It cools the converter gas and generates steam which is cooled and collected in the boiler for further

use.

Technical Specifications:

Capacity of SMS-1=2.5MT/year

No. of Converter=5(100/130T each)

No. of lances/converter=2 each (280/320NM3

/min)O2

Mode of combustion=Free Combustion.

STEEL MELTING SHOP-2

Introduction:

SMS-2 differs from SMS-1 because of blowing process and converter gas system.The mode of

combustion in SMS-2 is suppressed combustion where atmospheric air is not allowed in hood area

and the combustion of converter gas is suppressed which is further used as a flue.

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Inputs:

Hot Metal from the blast furnace.

Outputs:

Semi-Skilled or killed steel to continuous casting m/c exclusively.

SECTIONS:Major sections of SMS-2 are outlined below:

Mixer: Same as that of SMS-1.

Two converters of suppressed combustion type are there.

Converter Details:

FluxLD Slag

Dolomite LimeJaisalmer Lime

Lime Stone

Oxygen (pr. 18kg;purity 99.5%)

Six hole water cooled lancewith Cu tip TAP HOLE

Charge:-

Hot metal (270T)+Scrap (25 to 30 T)%Si / (.60 to .65)


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Oxygen blowing :-

being done by six hole lance (copper tip) water cooled.

Pressure 18 Kg, Min and Purity 99.3% Min.

Mixer Metal :-

collected from mixer (2 nos. 2500T capacity)

%C = 4 to 4.5

Si = 0.55 to 0.65 (Aug 0.60)

S = 0.045 Max.

P = 0.15 Max

Total Blowing time :- 16 to 16.5 Min

Flux will be added within 8 to 10 of blow.

Sequence =1) 8T Lime initially2) 4T L. D. Slag

3) Rest 12T Lime

4) Lime Stone is to added as a coolant

(if required)

Tapping Temperature is to be aimed > 1680 to 1700C

Metallic Charge will depend on % Silicon content of hot metal.

Considering

0.60% Silicon Hot Metal 270T to 275T

& Scrap 25T to 30T

Refractory lining of the converter is having MCB i.e. Mag Carbon Bricks.

Tapping time 6 min is being maintained.

After that tap hole is being repaired / changed.

Pre/post slag arrester is being used to avoid the carry over slag.

Combined blowing facility is also having in converter through 12 nos. of elements at the

bottom of the converter.

There are three procedure:

1. Proc. 5 i.e. upto 14 Nitrogen then Argon till tapping finish.

2. Proc. 7 i.e. upto 9 Nitrogen then Argon till tapping finish.

3. Proc. 6 i.e. 100% Argon from blow start to tapping finish.

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Steel Refining Unit:

This unit homogenizes the temperature and chemical composition of liquid steel received from

different LD converters. De-sulphurisation of steel is done up to a sulphur level of 0.01%.Chemical

composition of steel is also done by adding pre-requisite quantity of Ferro-alloys. End point temp.

Control of liquid steel is done by heating/cooling the melt.

Continuous Caster:

It is the heart of SMS-2 and has the following main point.

Tundish:

Refractory lined buffer vessel designed to continuously feed liquid metal from ladle to CC mould at

regulated flow rate.Mould:

Solidification of liquid metal starts here. It is generally made by copper using primary cooling

mode. At the beginning of casting a dummy bar is inserted inside the mould to avoid free fall of

steel. Continuous lubrication between mould wall and steel is done by mould powder. It also acts

as a coolant.

Secondary Cooling Zone:

Partly solidified after leaving the mould enters its secondary cooling zone comprising arrays of

rollers and water spray-nozzles. Roller support and guide its downward movement of strand and

water spray cools the strand resulting its complete casting.

Straightening Rolls:

These are located at the end of st 2 where fully solidified strand is straightened by pairs of

internally water cooled rolls and made to move over horizontally placed roller tables. After the

strand has been straightened, it is cut to required length using acetylene torch cutting machine.

HIGHLIGHTS OF BSL CONCASTER

Mould-Straight with adjustable withdrawing cooling.

Dummy bar system-Top charging

Containment-Segmental design

Bending-Continuous with 8 mm curvature.

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Roller Type-Split design

Metallurgical Length-29.5m

Cooling-Air mix cooling

Automation-Mould level control, Turndish level control, secondary cooling, breakout

prediction, Computer aided quality assurance, Material tracing. etc.

Advantages of CCS:

Higher Yield

Lower energy consumption.

Lower operating casts

Elimination of primary mills.

CONTINUOUS CASTING SHOP

Introduction:

All the crude steel was processed through the conventional ingot route .But keeping in view the

benefits of continuous casting such as low investment/production cost, energy efficiency, better

quality and improved pollution control, Bokaro steel plant updated by replacing the ingot route by

installing continuous casting in SMS-II.

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Concast shop is provided with a SRU, caster, Turndish Preparation area, Slab area, Slab yard and

RERS (Replaceable equipment repair shop).

SRU

In SRU the steel is refined to make it suitable for casting of desired quality. First the steel is killed

by removing O2 to


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The shop houses two cranes of capacity 55/10t and one crane of capacity 16/5t.It has got

three sections i.e. roller repair, mould repair and alignment general repair section.

Features of CCM:

Type of Machine : Low head machine with straight mould and.

Segmented stranded guide.

Length of mould : 900mm

Number of strands : 2x2

Cooling bow radius : 8 meters.

Machine speed : 0.2M/min-1.9M/min.

Cooling : Air mist cooling.

Casting Size:

Thickness : 200mm, 225mm, 250mm

Width : 950-1850mm

Length : 9-10.5metres

Others

Metallurgical length : 29.7metres

Dummy Bar : Top charging

Cutting system : Torch cutting (acetylene)

Average heat size : 302T

Tundish capacity : 50T

SLABBING MILL

Introduction:

Slabbing Mill acts the primary means producing slabs of different specifications by rolling the steel

ingots from SMS-1 but with the advent of continuous casting roots, the slabbing mill has been

rendered useless.

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Inputs:

Ingots from stripper yard of SMS-1(Size: 17T, 20T, 25T, 28T)

Outputs:

Slab for internal customers i.e. HSM as well as external customers.

Functioning:

The main function of slabbing mill is heating, rolling and conditioning.

Sections:

There are four major sections.

Ingot Storage Yard:

It has a capacity to store70000T of Ingots and served with two 75/20T over head tong crases.

Soaking Pit:

With the help of soaker cranes (50/40T) ingots are charged into the soaking pits where they are

heated by mixed gas to a temperature of 1300o +20o C for about 3-4hrs for hot ingot and up to 10hrs

for cold ingots. Soaking pit is lined with refractory material.

Mill Proper:

After soaking is complete the ingots are taken out and placed on a roller table in a tilter. For the

above purpose ingot buggy and pusher car are used. The receiving temperature is about 1250o Cat

which slab is rolled. Actually mill proper has been divided into parts which are:

Post-1-Pushing the ingot from tilter to roller table.

Post 2- Hot working /Milling of ingots are done here. The mill is of universal type, since rolling of

ingots can be done from all sides. The mill produces slab of thickness 150-300mm and width 750-

1850mm and length up to 10300mm.The mills has two horizontal rolls of diameter1250mm and

two vertical rolls of diameter 1000mm.The power required for the horizontal rolls is 6.7MW and

vertical rolls is 1.85MW.Rollers are balanced hydraulically and thickness is controlled by moving

the gap between the rolls.

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Post 3- Hot/ Cold Scraffing of rolled slab is done here.The mill uses oxygen flame to melt 1mm

sheet of slab so as to remove surface defects Viz:-scabs, blisters, embedded scaleetc.scarfing

losses is about 2% of total ingot weight.

Post 4- With the help of shearing hydraulically the fish tail of slab is cut from front end and tail

end. Slab length is maintained at a desired length.

Post 5- Piling up of various slabs for sending to slab yard with the help of two pillars is done.

Slab Yard:

It receives and stock slabs which are further supplied to HSM. It is also required to theexternal customers. Whole slab yard area is divided in to Stacks and further piling is done in a

particular manner with 15-16slabs in a single pile.

HOT STRIP MILL

Introduction:

The plastic deformation of a metal above its recrystallisation temperature by squeezing it between a

pair of rolls is called hot rolling. The HSM at BSL is of continuous 2000mm mill. It is referred as

2000mm mill because the barrel length of the rolls used in this mill is 2000mm.

Inputs:

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Slabs from slabbing mill and CCD.

Output:

Slabs with dimensions:-

Thickness 170 to 230mm

Width 950 to 1650mm

Maximum weight 28 tonn

Length 7700 to 10500mm

Coils with dimensions:

Strip thickness 1.9 to 12mm

Strip width 950 to 1650mm

Maximum weight 27tonn

Coil inside diameter- 850mm

Coil outer diameter 2300mm

Sections:

There are 11 posts and their function is outlined below:

Post 1: Control movement of slab transfer car, kick of end roller table no.10,11,12,13.

Post 2: Regulate the movement of pushers and the roller table in front of the number 1 & 2.

Post - 3: Pusher of furnace 3 and roller table in front of furnace 3.

Post 4: Discharging of slabs from furnace 3 and roller table in front of furnace 3.

Post 5: Hot charging of slabs from slabbing mill and receiving bick balk slab/dummy bars.

Post - 6: Direct feeding of hot slab from post no. 5.

Post 7: Discharging of slabs from furnace 1&2.

Post 8: Consist of roughing group, guides, VSB and de-scalars.

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Post 9: Consists of finishing tables (strands), AC & coopers.

Post 10: Consists of flying shear.

Post 11: Consists of coilers, ROT & conveyors operation is controlled.

Main Units:

Reheating Furnace:

Its principle function is to heat the cold or hot slabs to the rolling temperature of

1250oC.It has three main sections:

Slab Charging System

Furnace Proper

Slab discharging system

Evaporation Cooling System:

Its purpose is to Cool the Skid pipes using de- aerated and dematerialized water at its

boiling point at 7-8kg/cm2 pressure. Each furnace has 3 4 skid pipes.

Roughing Group:

The roughing group train consists of vertical scale breaker, 2 high roughing stands and

four high universal roughing stands followed by finishing stand.

Finishing Stand:It consist of flying shear, finishing scale breaker and seven four (4- high) finishing

stand. It is followed by run out table.

Coilers:

Mill is provided with four coilers out of which two are continuously used where as third

is called hot spare coiler,coilers are designed for coiling of 12mm thick strip.

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HOT ROLLED COIL FINISHINGIntroduction:

Though HRCF is situated at a distance from HSM mill still it is considered as part of HSM.In hot

rolled coil finishing the coils are rolled in the 2000mm wide strip mill and are further subjected to

shearing and slitting process to obtain slit and sheet coils of desired and pre determined sizes as

per customer needs.

Sections:

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Major sections of HRCF are

Coil Yard

Shearing and Slitting lines -1&2

Off gauge shearing lines

Additional coil yard

Shipping area

HSM

HRCF

COIL YARD ADDITIONAL COIL

YARD

CRM DESPATCH

SHEARINGLINE- 1

SHEARINGLINE-2

HR PLATE HR SHEET

HR PLATE / SHEET

YARD

DESPATCH

SHEARING

LINE

HR coil

SHIPPING

FLOW DIAGRAM OF HRCF MATERIAL

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UNIT NAME PRODUCTS CAPACITY

Sheet shearing line 3.10X1850mm sheet 645000T/tear

Unit no. 1 2.5m-12mm length

Sheet shearing Line 2 1.5-4X1850mm sheet 475000T/Year

1.5-6m length

Coil slitting Line 1.5-8X1350mm,150mm 400000T/year

Min width slit coils

Coil Yard:

It is meant for storing the coils. It is connected to HSM by conveyor. Coil yard is housed in LM bay

and is having storage of 1200sq.mm with 8-13 days of storing capacity. It is serviced by 6 EOT

cranes of 50/10T capacity fitted with lifting tongs.

The internal customers of HRCF are cold Rolling mill. Coil is stacked in coil yard in such a manner

that best utilization of space is achieved according to size of material. Proper inventory and record

should be kept for smooth perfect operation of coil yard.

Shearing and Slitting line:

This line is situated in KL bay of HRCF .All the finishing lines have their feeding point situated in

coil yard and outlet in finishing shipping area. Shearing line no. 1 is primarily used for shearing

thick gauge material and line no. 2for thin gauge material. All the strips above 5 mm in thickness

are shearing in line no. 1and below 5mm thickness are sheared in line no. 2 i.e. plates in line no.1 &

for sheet in line no. 2.

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COLD ROLLING MILL

Introduction:

Cold rolling mill is defined as a compressive deformation process in which there is either a

continuous or stepwise deformation with more than one rolls. Hot rolled steel is generally cold

rolled at ambient temperature to produce material of following characteristics:-

Thinner gauge material

Material with improved strength

Bright smooth and dense surface finish

Inputs:

Coils from HSM through HRCF

Products:

Sheet Gauges

Sheet gauges

Sail Auto

SAILCOR

Galvanized Sheet

Tin Mill

Black Plates(TMBP)

SECTIONS:

Major sections of CRM complex along with their functions are:-

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Pickling Lines:

The strip of coil coming from HSM has a layer of scale(mixture of different iron oxides) with a

thickness of 5-20.The strip is de-scaled with a combination of mechanical and chemical

dissolution in pickling line. Removal of scale is performed by chemically treating the surface of hot

rolled strip with acid. In BSL there are two continuous pickling line consisting of un-coilers,

welding m/c, loopers, acid tanks and coiler.PL-1 is H2SO4 line where as PL-2 is HCL line.

\

Tandem Mill:

HR COIL130000

PL-I45000

PL-I61000

TM-I63000

TM-II42000

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In Tandem mill pickled strip is fed between every hard rolls in a continuous fashion where the strip

is engaged in several roll stands simultaneously enabling high tension force is applied.The roll

arrangement is 4-high with five strands. Application of coolant water with mineral oil emulsion is

provided continuously during cold rolling thus reduces the friction and heat generation at the roll

bite. There are two tandem mills i.e. Tandem Mill -1 and Tandem Mill-2 with Tandem Mill-2 being

automated.

TM-I

63000

ANN-III

15000

ANN-II

30000

ANN-I

30000

SPM-I

45000

SPM-II

25000

SSL-I

8000

SSL-II

5000

SSL-III

3000

CR SHEET CR COIL

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Annealing Zone:

During cold rolling the material is work hardened which causes loss in ductility and build up of

internal stresses. Annealing of cold rolled strip is carried out in order to eliminate internal stresses

and to restore the lost ductility and grain structure. Annealing involve heat treating the strip to a

temperature of 600-650o C. In BSL annealing area is divided into three sections.,AN-1,AN-2,AN-

3.The total CRM complex is divided in to following three zones:-

Zone 1:

It comprises of PL-1 &2, TM-1&2

Zone 2:

It comprises of:-

Hood Annealing 1 & 2(EF Bay)

2000mm 4 High single stand non-reversing skin pass mill.

1420mm,4 High stand non reversing SPM-2

TM-II

42000

ECL

9000

CAL

9000

HDGL

18000

DCR15000

TMBP

4000

GP/GC

GC

SHEE

T

GP

SHEE

T

FULL

HARD

GP

COIL

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Sheet shearing lines no.1,2,3,4&5

Slitting line no. 1&2

Zone 3: It comprises of:-

Hood Annealing 3

Electrolytic cleaning

Continuous annealing line(CAL)

Double Coil Reduction mill(DCR)

Shipping Bay

Hot dip galvanizing line(HDGL)

HDGL shipping bay

HDGC: This consist of the following sections:-

Hot dip galvanizing line

Continuous coil corrugation line

Galvanized sheet shearing line

Auxiliaries: This comprise of:-

Anti corrosive shop

Metal tone shop

Area repair shop

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ROLL GRINDING AND BEARING SHOP

Main Function:

To ensure time by supply of ground/turned/short blasted and assembled rolls to

slabbing mill, Hot strip Mill and Cold Rolling Mill.

To provide supply and maintain the rolls of various mills to grind them as per

the required norm,finish and rough to achieve max. life rolls.

To assemble, disassemble, inspect maintain various types of chokes, roll neck

bearing including the antifriction bearing.

To reclaim rolls by roll welding in order to achieve max. roll economy.

Grinding of shear blades of HRCF, CRM and add jobs.

Set up & facility:

There are four settings in RGBS

1) RGBS (HSM) This caters to the needs of slabbing mill and HSM.

2) RGBS (CRM) This shop serves to Tandem Mill, skin Pass mill-1, Pickling line

rolls associated with tandem Mill-1 and shearing Line.

3) RGBS (CRM-2) serves to Tandem mill 2, SPM 2, HDLG and Pickling line

2.

4) Planning and Maintain system It deals with planning and maintenance.

Equipments:

Roll grinding m/c:

It is used for grind of used rolls from various mills and to impart required surface finish &

crown on them after each campaign. We have total no. of 10 grinding m/c , Russia & Japan

make.

Roll turning Lathe:

It is used for turning of slabbing mill rolls of HSM, where turning finish is sufficient.

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Roll Welding m/c:

Horizontal and vertical rolls of slabbing mill, vertical stand rolls and edges rolls of strips mill

are reclaimed by this m/c.

Work roll assembly/disassembly m/c:

It is used for taking out chocks with bearing from used olls return from mill & subsequent

assembly on ground rolls.

Back up roll assembly/disassembly m/c:

Washing m/c:

Roll assembly are washed with spray of hot water to remove the accumulation of screw down

grease, mill scale etc.Shot Blasting m/c:

It is used to give rough surface finish to increase bite & avoid sticking during annealing and

also to enable roll product to retain subsequent painting.

Polishing m/c:

Sleeve journals of oil film bearing are polished on this m/c to a very high degree of finish using

extra fine mery paper. This improves working life of bearing.

Chock tilter:

It is used for tilting of back up roll chocks during assembly /disassembly of oil filled bearing at

various angles to facilitate the assembly/removal of various parts.

Tanks:

It is used for washing/cleaning/lubricating process.

Low freq. induction hardening m/c:

It is used for hardening of rolls from 400 to 700 dia. & 50,000 mm in length.

Vertical annealing furnace:

Used rolls with residual stress are annealed in the furnace in order to give the roll to adequate

condition for re-hardening treatment, preventing cracks in rapid heat up, conditioning the

structure suitable for re-hardening.

Tempering furnace:

It used for stabilization process after re-hardening operations.

Ultrasonic flow detector:

It is used to detect & determine location of internal defects on barrel & neck of rolls.

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plan induction report

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