Vocational Training in Steel Authority of India Limited (SAIL)-Bokaro Steel Plant

1Vocational Training Report
VOCATIONAL TRAINING REPORT
Industrial training at:-
Steel Authority of India Limited (SAIL),
Bokaro Steel Plant,
Bokaro steel city, Jharkhand
Submitted in partial fulfillment of the requirements of the degree of
B.TECH
MECHANICAL ENGINEERING
By
SUMIT KUMAR
3RD
Year (5th
semester)
Institute of Engineering & Management, Kolkata
Dated :- 24th
Dec, 2016

CERTIFICATE
This is to certify that SUMIT KUMAR, from Institute Of Engineering &
Management, Kolkata has undergone training in “Steel Authority of India
Limited (SAIL), Bokaro Steel Plant, Bokaro, Jharkhand” for a period of 28 days
from 28th
Nov 2016 to 24th
Dec 2016, under my guidance.
His performance was satisfactory so as to fulfill all the requirements for
successful completion of the training.
Date: - __________________ _____________________
(Signature)

ACKNOWLEDGEMENT
I would like to express my sincere gratefulness and profound gratitude to Steel
Authority of India Limited for providing an opportunity to undergo
Vocational training of 1 month in “Bokaro Steel Plant, Bokaro Steel City,
Jharkhand”
I bear immense pleasure in expressing my gratitude and thanks to all the
Employees of respective shops for their honest teaching, practical
demonstration, guidance and suggestion in respective shops.
Furthermore, I would like to acknowledge with much appreciation the crucial
role of the staffs, who gave us the permission to use all required equipment and
the necessary materials during our training period.
This training wasn't possible if HOD of mechanical department MR. Tapobrata
Bhattacharya of IEM, KOLKATA wouldn't have allowed us in the first place, so
thanks to him as well.

CONTENTS
1. Introduction
2. PROCESS FLOW OF STEEL PRODUCTION
3. Shop description
3.1 Raw Material Handling Plant (RMHP)
3.2 Coke-Oven & By Product Plant (CO & BPP)
3.3 Sinter Plant (SP)
3.4 Blast Furnace (BF)
3.5 Steel Melting Shop (SMS) & Continuous Casting Shop (CCS)
3.6 Slabbing Mill (SM)
3.7 Hot Strip Mill (HSM)
3.8 Hot Rolled Coil Finishing (HRCF)
3.9 Cold Rolling Mill (CRM)
4. Products and Market of Bokaro Steel Plant
5. Conclusion
6. References

1. INTRODUCTION
Steel Authority of India Limited is India’s largest steel producing company and ranks 18th in the World.
It was founded in 19th January 1954 with headquarter at New Delhi. It was incorporated to central public
sector on 24 January 1973. With an annual turnover of Rs. 49350 crore, the company is among the seven
Maharatnas of the country’s Central Public Sector Enterprises.
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. It has been possible through 5 integrated plants and 3 special steel plants which employs
over a lakh of employees and produces 13.5 million metric ton of steel annually. Along with this there are
various subsidiary and joint venture plant set up with SAIL.
SAIL has its own Research and Development Centre at Ranchi to examine and improve the quality of steel
production and update the technologies to be in par with rest of the world. Besides, SAIL has its own in-
house Centre for Engineering and Technology (CET), Management Training Institute (MTI) and Safety
Organization at Ranchi. For promoting and selling various long and flat products produced in domestic
market and abroad, SAIL has its own Central Marketing Organization with branches spread all across the
India and world. SAIL's International Trade Division ( ITD), in New Delhi- an ISO 9001:2000 accredited
unit of CMO, undertakes exports of Mild Steel products and Pig Iron from SAIL’s five integrated steel
plants.
Sail Integrated Plants:
1. Raurkela Steel Plant
2. Bhilai Steel Plant
3. Durgapur Steel Plant
4. Bokaro Steel Plant
5. IISCO Steel Plant
Special Steel Plant
1. Alloy Special Steel Plant, Durgapur, West Bengal
2. Salem Steel Plant, Tamil Nadu
3. Visvesvaraya Iron and Steel Plant, Karnataka
Subsidiary
 Maharashtra Electrosmelt Limited (MEL) in Maharashtra

Joint Venture
 NTPC SAIL Power Company Pvt. Ltd (NSPCL)
A 50:50 joint venture between Steel Authority of India Ltd. (SAIL) and National Thermal Power
Corporation Ltd. (NTPC Ltd.); manages the captive power plants at Rourkela, Durgapur and Bhilai with a
combined capacity of 314 megawatts (MW). It has installed additional capacity by implementation of 500
MW (2 x 250 MW Units) power plant at Bhilai. The commercial generation of 1st Unit has commenced in
April’2009 and 2nd Unit is likely to start commercial generation by July 2009.
 Bokaro Power Supply Company Pvt. Limited (BPSCL)
This 50:50 joint venture between SAIL and the Damodar Valley Corporation formed in January 2002 is
managing the 302-MW power generating station and 660 tons per hour steam generation facilities at
Bokaro Steel Plant. BPSCL has proposed to expand its capacity by installing 2x250 MW coal based
thermal unit at Bokaro. In addition, construction activities are underway for installation of 9th Boiler
(300T/Hr) & 36 MW Back Pressure Turbo Generator (BPTG) project at Bokaro.
List of Sail Customers
Industry Type of steel used
Railways Wheels, axils, rails, plates, sheets
Shipbuilding and Engineering sector Heavy plates, sheets
Construction works, Bridges TMT bars, rods, structural steel
Packaging and Automotive Steel plates
Consumer durables Ultra-thin cold rolled sheets
Air conditioning ducts, roofing, paneling Galvanized steel
Motors, Generators, electrical applications Electrical steel
Transportation of oil, gas, water Steel pipes
Industrial and Consumer use Stainless steel
Defense
Special grade steels (Armour grade steel, warship
grade steel, bullet proof steel and many other defence
grade steel)
Special Product :- Rocket Launcher, Agni Missile, INS Vikrant, Arjun Main Battle Tank,
Armoured Vehicles

Major Units of SAIL
Steel Plant Location Major Products
1. Bhilai Steel Plant Bhilai, (Chhattisgarh)
Plates, Rods, Rail Tracks,
Structurals,TMT, Merchants
2. Durgapur Steel Plant Durgapur, (WB)
Structurals, Wheels & Axles,
Skelp
3. Rourkela Steel Plant
Rourkela,(Orrissa) Plates, Coils, Pipes, GP/GC,
Silicon Steel
4. Bokaro Steel Plant Bokaro, (Jharkhand)
Plates, Coils, Sheets, GP/GC,
TMBP
5.
Indian Iron & Steel
Company Limited (IISCO)
Burnpur, (WB) Structurals, Rails, Bars, Rods
Special Steel Plant Location Major Products
5. Alloy Steel Plant (ASP) Durgapur, (WB) Alloy and special steel
6. Salem Steel Plant (SSP) Salem, (Tamilnadu) Carbon and Stainless steel
7.
Visvesvaraya Iron &
Steel Plant (VISP)
Bhadravati,(Karnatak) Alloy and special steel. Pig iron
Subsidiaries Location Major Products
8.
Maharastia Electrosmelt
Limited (MEL)
Chandrapur
(Maharastra)
Ferro-alloys
Some major products of SAIL are being marketed under the following brand names: SAIL
Boiler, SAIL TMT, SAIL NOX, SAIL Marine, SAIL TOR, SAIL Superform, Sail Tin,
SAIL Press, SAIL Jyoti, SAILMA, SAILCOR and Salem Stainless.
These products are proving beneficial to an array of applications in diverse fields

Bokaro Steel Plant
Bokaro Steel Plant is the fourth integrated steel plant of SAIL. Established in the year 1964 with Soviet
collaboration, it is the first Swadeshi Steel Plant of India with maximum indigenous components and
equipment. It was lately merged with SAIL first as a subsidiary and then as a unit under Public Sector Iron
& Steel Companies (Restructuring & Miscellaneous Provisions) Act 1978.
Its 1st blast furnace was started in 2nd October 1972 and on 26th February 1978 it completed the 1st phase
of 1.7 MT of ingot steel production. Presently it has five blast furnaces and a total capacity to produce 4.5
MT of liquid steel. With the continuous up gradation in technology incorporated, it is expected to cross
10MT target by 2016. The first shop of Bokaro Steel plant got the ISO 9001 certificate in 1994 and its
SAIL JYOTI products enjoy a loyal market.
Major Landmarks in the history of Bokaro Steel Plant
Years & Month Landmarks
1966, Jan Construction work started
1972, Sept First Coke Oven Battery and Sinter Band commissioned
1972, Oct First Blast Furnace commissioned
1973, Dec Steel Melting Shop - 1 started production
1974, Dec Trial rolling of slabs in Slabbing Mill
1975, Dec Hot Strip Mill commissioned
1976, Jan Hot Rolled Coil Finishing commissioned
1977, June Cold Rolling Mill Complex - 1 commissioned
1983, June Steel Melting Shop - 2 started production
1991, Sept Cold Rolling Mill Complex - 2 commissioned
1997, Sept Continuous Casting Shop started production

Bokaro Steel Plant is designed to produce a wide range of flat products:
 Hot rolled coils
 Hot rolled plates
 Hot rolled sheets
 Cold rolled coils(CRO)
 Cold rolled sheets
 Tin mill black plates (tmbp)
 Galvanised plain and corrugated (gp/gc) sheets
 Oxygen Gas Produced in Oxygen Plant.
 Hydrogen Gas
The new features added in modernization of SMS-II include two twin-strand slab casters along with a Steel
Refining Unit. The Steel Refining Unit was inaugurated on 19th September, 1997 and the Continuous
Casting Machine on 25th April, 1998. The modernization of the Hot Strip Mill saw addition of new
features like high pressure de-scalars, work roll bending, hydraulic automatic gauge control, quick work
roll change, laminar cooling etc. New walking beam reheating furnaces are replacing the less efficient
pusher type furnace.
A new hydraulic coiler has been added and two of the existing ones revamped. With the completion of Hot
Strip Mill modernization, Bokaro is producing top quality hot rolled products that are well accepted in the
global market.
Bokaro is designed to produce flat products like Hot Rolled Coils, Hot Rolled Plates, Hot Rolled Sheets,
Cold Rolled Coils, Cold Rolled Sheets, Tin Mill Black Plates (TMBP) and Galvanized Plain and
Corrugated (GP/GC) Sheets. Bokaro has provided a strong raw material base for a variety of modern
engineering industries including automobile, pipe and tube, LPG cylinder, barrel and drum producing
industries.
 Area of plant - 17,000 acre
 Township Area - 19,000 acre
 Carbon content is 1.5% in steel at Bokaro
Inside Bokaro steel Plant
 300 km railway truck
 100 rail crossing
 70 loco is present.
 10-12 gates are there for entry/exit in plant.

2. PROCESS FLOW OF STEEL PRODUCTION

Raw materials required for the production of steel are iron ore, limestone, manganese, dolomite, coke, and
sinter. These are supplied by RMHP, coke oven and sinter plant. Blast furnace is charged with iron ore
lump along with limestone, coke and sinter. Intense heat from in BF converts iron oxide to hot metal. This
hot metal is fed to Steel Melting Shop (SMS). Making of steel takes place here by blowing 99.95% pure
oxygen through the hot metal to remove impurities. Suitable alloys are added to produce different grade of
steel. Raw material such as limestone, ferrous alloys, dolomite, and aluminum are also required. The steel
ingot produced in SMS is goes to Slabbing mill where it is converted to rectangular slabs of appropriate
thickness. From the slabbing mill the slab goes to Hot strip mill. It also receives the slab form SMS 2
which is based on continuous casting. It directly produced slab without producing ingot. These slabs are
heated and made into sheets of different thickness in HSF. These steel sheets are rolled in the form of coil
in HRCF. These coils are cut in appropriate dimension as specified by the customer and packed for sale.
Also the coil from the HSF is sent to Cold Rolling Mill. It produces high quality Tin Mill Black plate and
galvanized product with better strength and finish. Cold Rolling is done at temperature below re-
crystallization temperature to produce thin gauge plate of high density. There is no heating of the coil here.
Hot Dip Galvanization complex integrated with CRM produces high quality zinc coated cold roll steel.
The detailed information about every department are given below –
1. Raw Material Handling Plant (RMHP)
2. Coke Oven and By-Product Plant (CO & BPP)
3. Sintering Plant (SP)
4. Blast Furnace
5. Steel Melting Shops (SMS 1 & SMS 2)
6. Continuous Casting Shop (CCS)
7. Slabbing Mill (SM)
8. Hot Strip Mill (HSM)
9. Hot Rolled Coil Finishing (HRCF)
10. Cold Rolling Mill (CRM)
11. Capital Repair (Electrical)
12. General Maintenance
13. Heavy Maintenance
14. Turbo Blower Station (TBS) and Outdoor Pipeline (ODPL)
15. Machine Shop
16. Foundry Shop
17. Central Base Repair Shop (CBRS)
18. Operational Garage(OG)

3. SHOP DESCRIPTION
3.1 Raw Material Handling Plant (RMHP)
Raw Material Handling Plant (RMHP) is one of the most important units of an integral steel plant. The
major input for steel making comes from mines to this section.
Raw Material Handling plant is meant for transporting materials from Raw material yard/Base mix yard to
various process units of the plant.
The raw coal is procured from various mines in Jharia coalfields and washed coal is received from Dugda,
Kathara, Giddi and Kargil washeries. The washed coal is unloaded from wagons by tipplers and stored in
closed bins (silos) each of capacity of 2500 tonnes. The raw coal is supplied to the plant by road transport
and is unloaded in bunkers manually. The daily requirement of coal during 4 MT stage is to the tune of
15,500 tonnes.
Lump and fine iron ore are supplied from the captive mines at Kiriburu and Meghahataburu in Singhbhum
district. The iron ore required to produce one tonne of hot metal is about 1.6 tonnes of lump and fine ore
together. Limestone and Dolomite are used as flux to remove impurities by forming slag both in Blast
Furnace and Converters. Limestone of Blast Furnace grade is received from captive mines located at
Bhawanathpur in Palamu district. Limestone of SMS grade is obtained from Kuteswar mines in Madhya
Pradesh. Dolomite, the other flux material for Sinter Plant is obtained from Tulsidamar in Madhya Pradesh.
Dolomite chips required for making Dolomite bricks is received from Bhutan. Other raw materials like
Manganese-ore, Bauxite, Ferro-Manganise and Ferro-Silicon are procured from non-captive sources.
Different raw materials handling by this department are as follows:
 Iron-Ore of different grades
 Limestone of different grades
 Dolomite of different grades
 Manganese
 Coals of different grades
Machines operated in RMHP :
 Wagon Tippler (A machine which rotate the wagon by 180o
to unload the coal present in it.
Capacity of 1 wagon is 70.6 to /1199 kg/m3)
 Stacker
 Reclaimer
 Bucket Wheel
Basic functions of RMHP are as follows:
 Release of different raw materials wagons from different mines by wagon tipplers.
 To do the blending by making homogeneous 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.

Basic customer departments of RMHP are as follow:
1. Refractory Material plant
2. Sinter plant
3. Blast furnace
The Raw Materials and Material Handling Plant receives blends, stores and supplies different raw materials
to Blast Furnace, Sinter Plant and Refractory Materials Plant as per their requirements. It also maintains a
buffer stock to take care of any supply interruptions.
 Layout of RMHP

Stacker
Bucket Wheel

3.2 Coke-Oven & By Product Plant (CO & BPP)
In an integrated steel plant, Coke-Oven & By Product Plant plays an important role.
It is a shop where coal is charged and converted to coke.
Coke Ovens at Bokaro are the tallest and largest built in India so far. In the first stage (1.7MT), four
batteries each of 69 ovens with facilities for coal handling and with complete by products recovery units
were built. Four more batteries of similar features have been added in 4 MT expansion stage which
includes one standby battery.
 80% coal comes from Australia & New Zealand.
 20% coal comes from India mainly kiriguru mines & regions from Dugda, Kathara, Kargali, Giddi,
Jharia, chandrapura, dhanbad, phusro etc.
 Ash % in coal of India is 27%
 Ash % in coal of Australia & New Zealand is 7%
There are 81 coal storage chambers where coal is stored and then from here coal is send to the charging
oven where coal is charged at a temp. of 900O
C to 950O
C.
After the coal is charged it is loaded in the quenching car which brings the charged coal to the quenching
chamber where it is charged and then it becomes coke.
It supplies coke, one of the two principal raw materials to the Blast Furnace. In addition to coke-oven gas
produced during coke manufacturing is used as major energy source within the integrated steel plant along
with B.F gas produced during combustion of coke in Blast Furnace.
The entire resources of coal can be classified into two groups:
1. Coking Coal
2. Non-Coking Coal
If the coal when heated to bright red in absence of air softens swells and eventually solidifies into a more or
less coke, it is classified as coking or caking coal. All coking coals are caking in nature but all caking coal
are not coking. Coking coal on carbonization gives metallurgical or blast furnace coke. Non-coking coal
fails to produce blast furnace coke on carbonization. The moisture, ash, sulphur and phosphorous content in
the coal play a vital role in deciding the quality of coke that will be produced in the coke-oven area. They
all should be on the lower side.
There are four sections in coke-ovens and by product plant, they are:
1. Coal Handling Plant
2. Coke-Oven Batteries
3. Coke Sorting Pit
4. By Product Plant
The main purpose of this plant is to produce quality coke in large quantities along with useful coke-oven
gas, while conserving limited reserve of quality coking coal and practicing economy in environment
control measures.
The process of making coke consists of destructive distillation of coal in the absence of air. The coal is
heated in a closed chamber thereby driving out of volatile components present in the coal and leave behind
the residue called coke. These closed chambers are known as Coke-Oven Batteries, there are 8 batteries in
BSL. There are 69 ovens in each battery. The carbonization temperature is usually kept in the range 1473k-
1573k.

The composition achieved after carbonization is
 Fixed carbon: 77%
 Ash content: 22%
 Volatile matter: 1%
A typical composition of coke-oven gas (CO Gas) is:
 Methane: 22-25%
 Hydrogen: 55-60%
 Nitrogen: 2-3%
 Carbon-monoxide: 8-10%
 Carbon dioxide: 4-6%
 Calorific value: 4200-4400Kcal/cubic meter
After coke is produced it is stored in different sizes according to the place of consumption, acid treatment
and absorption process in coal chemicals and By Product Plant. It is a technological necessity in order to
make Coke-Oven gas suitable for use as a major source of fuel in the steel plant.
The different by products produced are as follows:
 Crude tar
 Naphthalene
 Naphthalene oil
 Wash oil
 Press oil
 Pitch (Extra Hard Pitch & Hard Medium Pitch)
 Ammonium Sulphate
 Benzene
 Toluene
 Xylene
 Naphtha
 Benzol
The Coke Oven battery has 8 batteries with 69 ovens each, maintained meticulously in terms of fugitive
emission control, use of phenolic water and other pollution control means.

3.3 Sinter Plant (SP)
Sinter is porous agglomerate of mineral fines formed after incept fusion. Sintering is a process of preparing
sinter in which a high temperature is maintained for two basic purposes:
1. Waste management
2. Advantageous properties of sinter
Sintering as a process uses all 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 Blast Furnace. Now days, 70% of Blast Furnace burden is sinter.
The Sintering Plant in Bokaro is the largest in the country consisting of three machines with the production
capacity of 18,790 tonnes (gross) per day to attain the 4 MT stage capacity. Metallurgical wastes such as
the finer fractions of iron ore, lime stone, dolomite, coke, flue dust and mill scale which cannot be used in
the production process directly can, however, be formed in to an excellent charge material through a
process known as sintering.
 Iron Ore Fines
 Flux (limestone+Dolomite)
 Coke
 Sinter Return (own generation)
 Waste Materials like
1. Flux Dust (from blast furnace)
2. Mix scale (from Slabbing Mill & Hot Strip Mill)
3. L.D Slag (from Steel Melting Shops)
4. Calcined Dolomite (from Refractory Materials Plant)
5. Lime Dust (from Refractory Material Plant)
Different sections of Sintering Plant are:
 Raw materials section ( For crushing of coke and flux ): This sections deals with the raw
materials coming from the various sources and processes it to suit the needs of the Sintering Plant.
 Stock Bins & Proportioning Section ( For storing, proportioning & mixing ) : The function of this
section is to receive materials, prepare the raw materials and then store it in the bins. There are 23
bins /machine. The capacity of bins for various raw materials are:
1. Iron-Ore fines:3600T
2. Limestone fines:3000T
3. Coke Breeze: 1000T
4. Mix Scale & Flux Dust: 6000T
5. Hot & Cold Sinter: 1800T
 Waste Bin Section: This section receives wastes materials from different departments like flux dust
from Blast Furnace, mill scale from Slabbing Mill, limestone from Refractory Materials Plant. Then
these are proportioned and then send to the stock bins.
 Sinter Machine Section ( For sinter making ): This section has three machines producing 6.2 MT
sinter per year. Nearly 52KWH of power is consumed/tone of gross section.

Final Sinter Produced

3.4 Blast Furnace (BF)
Blast Furnace can be termed as the core metallurgical reactor for the production of hot metal. It is a
counter-current heat & mass exchange rector in which there is continuous transfer of mass (oxygen,
carbon, hydrogen) & thermal energy between descending burden materials and ascending gases generated
at tuyer level.
Iron present in the form of oxides in ore is extracted in the Blast Furnace by interaction of ore, coke and
limestone at high temperatures. Besides providing heat, coke reduces the iron oxides present in the ore.
Limestone and Dolomite combine with the impurities and form slag. This slag floats on the surface of the
hot metal in the furnace. Both slag and metal are tapped at regular intervals. The Blast Furnaces at Bokaro
are the largest in India having a useful volume of 2000 M Cube and a production capacity of 2640 tonnes
of basic iron per day. There are five Blast furnaces in 4 MT stage with total iron production capacity to the
tune of 4,585,000 tonnes per year. The charging system is fully automatic. Materials are fed in to skips by
means of converse. The furnace has a hearth diameter of 9750 mm, useful height of 29.6 m and has 20
tuyeres and 4 stoves with a total heating surface of 30,300 sq.m per stove.
The inputs required for the Blast Furnace are as follows:
 Iron-Ore Lamp
 Sinter
 Metallurgical Coke (25mm to 80mm)
 Lime-Stone
 Manganese
 Nut Coke
The outputs from the Blast Furnace are as follows:
 Hot Metal
 Blast Furnace (BF) gas
 Gangue Material in the form of slag
Different sections of Blast Furnace are as follows:
1. Raw Material Charging Section: This section receives raw materials from RMHP, Sintering
Plant, Cock-Ovens and then supplies them to the furnace top by means of a skip car.
2. Furnace Power: Raw materials are changed into it and then hot blast of air at 1373 K is supplied.
Due to the occurrence of exothermic reaction, reduction of iron oxide to hot metal takes place. It
has five main sections, they are as follows:
o Hearth
o Bosh
o Belly
o Stack
o Throat
3. Stoves: Hot air blast is supplied through stoves, which are maintained at 1523 K with the help of
combustion if mixed gas. The stoves have refractory lining of chrome-magnetite from inside & fire
clay lining from outside.

There are total 5 Blast Furnaces (2640 ton/day).
In the BSL, each having a volume of 2000cu.m and working volume of 1756cu.m.
A Blast of Hot air at 1373 k is temperature is given to the Blast Furnace.
This blast is given at a pressure of 3.2 Kg/sq.cm.
• Hot Metal Temperature 1460-14800
C
• BF Productivity: 1.4 T/m3
/Day
• Capacity of B F 4.585 MT of Hot Metal per annum
The hot metal from the furnace has the following specifications:
 Carbon=4.0-4.5%
 Silicon=0.6-1.2%
 Manganese=0.6-1.2%
 Phosphorous=0.25%
 Sulphur=0.05%
Cock Rate: Cock Rate is the amount of cock required per ton of hot metal.
Cock Rate at present is 560 Kg/THM. Earlier it was 630 Kg/THM
THM = Tone of Hot Metal
 Anemoscope is used to see complete combustion in furnace.

3.5 Steel Melting Shop (SMS) & Continuous Casting Shop (CCS)
Steel making involves the process of removal of impurities like carbon, Manganese, Sulphur, Phosphorous
and other impurities from the hot metal by oxidation and formation of basic slag.
Steel at Bokaro is produced by oxygen blending (L.D) process. There are five 130 ton and two 300 ton L.D
converters in Bokaro. The converters are charged with scrap, hot metal and fluxes. Pure oxygen is blown
through water-cooled lance with multi-orifice nozzle to remove impurities by oxidation and then steel is
made. Purity of oxygen used is 99.5%.
Approximately 60 cu m. of oxygen is used to produce one ton of steel. The tap-to-tap time for the 130 ton
and 300 ton converters is 60 and 80 minutes respectively.
To achieve optimum levels of performance ensuring maximum productivity, yield and quality in the
process of steel making, a process control computer has been installed in the Steel Melting Shop. Near the
Steel Melting Shop is located the Ingot Mould preparation shop. The moulds vary in size to enable
production of ingots ranging from 15.6 to 38 tonnes
There are two Steel Melting Shop (SMS), SMS-I & SMS-II. Three types of products are produced from
these shops. They are:
1. Killed Steel
2. Semi-Killed Steel
3. Reamed Steel
Apart from the hot metal from the Blast Furnace, the different raw materials required for the production of
steel are:
 Limestone
 Dolomite
 Aluminum
 Ferro-Alloys
The main functions of Steel melting shop are as follows:-
 Oxygen blowing process.
 It receives hot metals from blast furnace.
 Output of sms1 is in ingot form.
 Output of sms2 is in slab form.
 From sms2 it goes to continuous casting shop
 Steel melting- process of removal of impurities like carbon and silicon.

S.M.S.-I
There are five numbers of converters, each of 100-130T capacities. The total capacity of this shop is 2.5
M.T/year. For oxygen blowing there are two water-cooled lances. The oxygen pressure is 15-20 Kg/sq.cm.
Various sections of the SMS-I are:
1. Mixers: The mixer is of 1300 T capacity and the temperature is about 1573-1593 K. the mixer acts
as a buffer stock. Hot metal from mixture is supplied to converter by locos.
2. Converters: This converts hot metal into steel by oxidation following an exothermic reaction.
Lime, scrap & following hot metal are changed in a definite sequence and then oxygen lancing is
done. The lime and other additions are done during blowing through slide gate system. Lime is
added as a flux to maintain the basicity of the bath. Basicity is defined as the ratio of calcium oxide
& silicon oxide and is kept between 3-3.5.
3. Pit Slid: Steel tapped from this side into the teeming ladles (140 T) and is transferred to teeming
bay after proper de-oxidation.
4. Teeming Bay: Steel is poured from teeming ladle into moulds (placed in mould train) by operating
slide gate and sent to stripper yard.
5. Stripper Yard: The ready ingot is stripped here from the mould and sent back to the mould-
cleaning yard, where it is cleaned by water spray and coated with tar or graphite.
6. Waste Heat Boiler: It cools the converter gas and generates steam, which is cooled and collected in
the boiler for further use.
Data:
 Capacity of SMS-I: 2.5MT/year
 No. Converters: 0.5 (100-130 T each)
 No. Of Lances/Converter: 02(280-320 N Cu. m/min) Oxygen
 Mode of Combustion: Free Combustion
S.M.S.-II & C.C.S.
SMS-II differs from SMS-I because of blowing process and converter gas recovery system. The mode of
combustion in SMS-II is suppressed combustion where atmosphere air is not allowed in hood area and
combustion of converter gas is suppressed which is further used as flux.
Inputs: Hot metal from the blast furnace
Outputs: Semi-Killed or Killed steel to continuous casting machine exclusively.
Sections: Major sections of SMS-II are as follows:
 Mixer: The mixer is of 2500 T capacity and the temperature is about 1573-1593 K. The mixer acts
as a reservoir of hot metal, homogenizes it and maintains the temperature. It acts as a buffer stock.
Hot metal from mixer is supplied to converter by locos. There are two mixers in SMS-II

 Converters: This converts hot metal into steel by oxidation following an exothermic reaction.
Lime, Scrap & Following hot metal are charged in a definite sequence and then oxygen lancing is
done. The lime and other addition are done during blowing through slide gate system. Lime is
added as a flux to maintain the basicity of bath. Basicity is defined as the ratio of Calcium Oxide &
Silicon Oxide and is kept between 3-3.5. There are two converters of 300 T capacities each.
 Steel Refining Unit: This unit homogenizes the temperature and comical composition of liquid
steel received from different converters. Desulphurization of steel is done up to a Sulphur level of
0.01%. Adding pre-requisite quantities of Ferro-alloys also dose chemical correction of steel. End
point temperature control of liquid steel is done by heating or cooling the melt.
 Continuous Caster: It is the heart of SMS-II and has following main parts:
o Tundish: It is refractory liquid buffer vessel designed to continuously feed liquid metal from
ladle to continuous casting mould at regulated flow rate.
o Mould: Solidification of metal starts in the mould. Copper using primary cooling mode
generally makes it. At the beginning of casting, a dummy bar is inserted inside the mould to
avoid free fall of steel. Continuous lubrication between and steel is provided by mould
powder. It also acts as coolant.
o Secondary Cooling Zone: The metal, after leaving the mould enters in its secondary cooling
comprising arrays of rollers and water spray nozzles. Rollers support and guide its
downward movement of strand and water spray cools the strand resulting in complete
casting.
 Straightening Rolls: These are located at the end of strand 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 stand has been straightened, it is cut to required length using acetylene-
cutting machine.
C.C.S. :- There are two double stand casting machines capable of producing slabs of 950mm to 1850mm
width (cold). Thickness can be of 200mm, 225mm or 250mm. Converter metal of SMS is further refined in
the Steel Refining Unit (SRU) and cast into slabs in the casting machine. In the process of casting, metal is
poured into tundish from the laddle and from tundish, metal flows into caster mould. Normally it takes 60
to 65 minutes for casting 290-300 tonnes of metal in to slab. Depending upon the slab width, the rate of
pouring can be from 0.9 metres/minute to 1.8 metres/minute. The yield ratio (liquid metal to slab) in caster
is 97-98% where as in earlier route (liquid metal-ingot-slab) yield ratio is about 80%. In caster, chemical
uniformity from slab to slab is better. Now plant is producing better quality slabs at lower production cost
after modernization.
Advantages of Continuous Casting:
1. It gives higher yield.
2. Energy consumption is low.
3. Operating cast is low.
4. Role of primary mills gets eliminated.

5. 3.6 Slabbing Mill (SM)
Slabbing mill acts as the primary means of producing slabs of different specifications by rolling the steel
ingots SMS-I, but with the advent of continuous casting route, the slabbing mill has rendered useless.
Inputs: Ingots from stripper yard of SMS-I.
Outputs: It provides slab to the internal customer i.e. Hot Strip Mill (H.S.M) as well as to the external
customers.
Functions: The main function of Slabbing Mill is heating, rolling and conditioning.
Sections: There are main sections in the Slabbing Mill, they are:
Ingot Storage Yard: It has a capacity to store 70,000 T of ingots and served with two 75 T overhead tong
cranes.
 Soaking Pit: With the help of soaker cranes ingots are charging into the soaking pits where they are
heated by mixed gas (C-O gas &B.F gas) to a temperature of 1553K-1593K for about 3-4Hrs for
hot ingots and up to 10Hrs for the cold ingots. Soaking pit is lined with refractory material.
 Mill Power: After soaking is completed, the ingots are taken out and placed on the roller table in a
tilter. For the above purpose ingot buggy and pusher cars are used. The receiving temperature is
about 1523 K at which slabs are rolled. The mill proper is has been divided into parts which are as
follows:
1. Post I: Pushing the ingots from the tilter to the roller table
2. .Post II: Hot working or milling of ingots is done here. The mill is of universal type, since rolling og
ingots can be done from all sides. The mill produces a slab of thickness 150-300mm &width750-
1350mm and length up to 10,300mm. The mill has two horizontal rolls of diameter 1250mm and two
vertical rolls of diameter 1000mm. Rollers are balanced hydraulically and thickness and thickness is
controlled by moving gap between the rolls.
3. Post III: Hot or cold scarfing of rolled slab is done here. The mill uses oxygen flame to melt 1mm
sheet of slab so as to remove surface defects viz. scarfing losses are about 2% of total ingot weight.
4. Post IV: Here, the fish tail of slab is cut from the front end & the tail end with the help of shearing
line.
5. Post V: Here, online painting/making & slab weighing is done.
6. Post VI: Here, piling up of various slabs for sending to slab yard with the help of two pillars is done.
 Slab Yard: It receives & stocks slabs, which are further, supplied to the HSM. It is also required
for the purpose of supplying to the external customers. The total slab yard area is divided into
stacks and further piling is done in a particular manner with 15-16 slabs in single pile,
Working- Slabbing Mill produces slabs depending upon the type of ingots and type of finished products
desired. The ingots are placed in the soaking pits where they are heated to a rolling temperature of about
1250 degree C. The hot ingots are then rolled in the universal slabbing mill. Hot slabs are cut on a 2800
tonne shear to a maximum length of 10.5 M. The slabbing mill capacity ranges between 600 and 800
tonnes/hour of ingot depending on the ingot sizes and the rolling cycle which varies fi-om 75 to 100
sec/ingot.
The slabbing mill is fed with rimming and semi-killed steel ingots of up to 30 tons. Hot slabs are cut to a
maximum length of 10 .5 m. The cut slabs are marked, weighed and taken to the slab yard for storage,
inspection and hand scarfing if required, and then charged in the continuous reheating furnace for rolling.

3.7 Hot Strip Mill (HSM)
The plastic deformation of metal above its re-crystallization temperature by squeezing it between a pair of
rolls is called hot rolling. The Hot Strip Mill, here is continuous 2000mm mill. It is referred to, as 2000mm
mill because the barrel length of rolls used in this mill is 2000mm.
Inputs: The input in this section comes from Slabbing Mill & C.C.S.
Outputs: It produces slabs with the flowing dimensions:
 Thickness: 170-230mm
 Width: 950-1650mm
 Maximum Weight: 38 T
 Length: 7,700-10,500mm
It produces coils of the following dimension:
 Strips Thickness: 1.9-12mm
 Strip Width: 950-1650mm
 Maximum Weight: 27 T
 Coil Inside Diameter: 850 mm
 Coil Outside Diameter: 2,300 mm
There are five main units in the Hot Strip Mill, they are as follows:
1. Reheating Furnace: Its principal function is to heat the cold or hot slabs to the rolling temperature
of 1523 K. It has three main sections, they are:
1. Slab Charging System
2. Furnace Proper
3. Slab Discharging System
2. Evaporation Cooling System: Its purpose is to cool the skid pipes, using deaerated &
dematerialized water at it boiling point at 7-8 Kg/sq. cm pressure. Each furnace has 3-4 skid pipes.
3. Roughing Group: The roughing group train consists of a vertical scale breaker, two high roughing
stand and five high universal roughing stands, followed by seven finishing stands.
4. Finishing Stands: It consists of a flying shear, finishing scale breaker & seven (four-high) finishing
stands and run-out table follows it.
5. Coilers: Mill is provided with four coilers out of which two are continuously used and other two
are spare coilers. Coilers are designed for coiling up to 12mm thick strip.
Working - Slabs brought to the Hot Strip Mill are heated in reheating furnaces before rolling. Hot slabs
discharged from the reheating furnaces are taken to the mill proper on roller tables and rolled to the desired
thickness. Prior to modernization it was capable of rolling strips of 1.5 to 10 mm thickness. Now it can roll
the slab to an even lower thickness (up to 1.3 mm). Now there is less variation in thickness of the coil
along the longitudinal direction due to faster response of the control system. Finishing stands have been
modernized with hydraulic AGC. There are four hydraulic coilers in the HSM.

3.8 Hot Rolled Coil Finishing (HRCF)
Through Hot Rolled Coil Finishing (HRCF) is situated at a distance from HSM, still it is considered as part
of HSM. In HRCF mill, the coils are rolled in the 2000mm wide strip mill and are further subjected as
shearing and slitting process to obtain sheet & slit coils of desired and pre-determined sizes as per the
customer needs.
Major sections of HRCF are as follows:
 Coil Yard: It is meant for storing the coils. It is connected to HSM by inter-shop conveyors. Coil
yard has a storage capacity of 1200 sq. m, it is serviced with 6 cranes of 50/10 T capacity fitted with
lifting tongs.
 Shearing & Slitting Lines (1& 2): This is a finishing line and all the finishing lines have their
feeding points in the coil yard and outlet in the finishing shipping area. Shearing Line 1 is used for
shearing trick gauge material (above 5mm thick) and line 2 for thin gauge material (below 5mm
thick). Plates are sheared in line 1 and sheets in line 2.
 Off Gauge Shearing Lines: These shearing lines are used to provide finishing to the materials
already sheared in the Shearing lines.
 Additional Coil Yard: This Coil Yard provides with extra storage space.
 Shipping Area: This area is used to load the finishing products (coil or sheets) in the wagons and
then these are sent to the customer or to the different stockyards in different parts of the country and
also in abroad.

3.9 Cold Rolling Mill (CRM)
Cold rolling can be defined as a compressive deformation process in which there is either a continuous or a
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 & Dense surface finish
Inputs: Coils from HSM through HRCF
Products: Sheets & Coils of different dimensions
Major sections of CRM are as follows:
1. Picking Lines: The strip of coil coming from HSM has a layer of scale (mixture of different iron
oxides) with a thickness of 5-20 micrometre. The strop is decaled with a combination of mechanical
& chemical dissolution in picking line. Removal of scale is performed by chemically treating the
surface of hot rolled strip with acid. Here, there are two continuous picking lines consisting (PL-I is
Sulphuric Acid line & PL-II is Hydrochloric Acid line) of uncoiled, welding machine, lopper, acid
tank and coiler.
2. Tandem Mill: In Tandem Mill pickled strips is fed between vary hard rolls in a continuous fashion
where the strips is engaged in several rolls 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 the cold rolling thus reducing the friction and
heat generation at the roll site. There are two tandem mills i.e. TM-I & TM-II. TM-II being
automated.
3. Annealing Zone: During the cold rolling the material is work hardened which causes loss in
ductility & build-up of internal stress and to restore the lost ductility and gain structure. Annealing
involves heat treating the strip to a temperature of 873-923 K. There are three annealing lines in the
CRM.
4. Hot Dip Galvanizing Section: In this section the coils are uncoiled, heated and then galvanized in
the liquid zinc. Galvanization is a process in which of coating of zinc is done on the surface of steel
so that it can be protected from rust and other atmospherics hazards. This section consists of the
following different section.
5. Skin Pass Mill-I & Skin Pass Mill-II
6. Shearing Line I & II
7. Slitting Line and Shipping line
After the required processes are completed in the Hot Dip Galvanizing Section are done, then the coils or
the corrugated sheets are packed and then these are sent to the customer or to the different stockyards in
different parts of the country and also in abroad.

Working - The starting material for the Cold Rolling Mills is a hot strip of 1.5 to 6 mm thickness in the
form of coils. The oxidised surface scales are removed from hot rolled coils in the pickling line by
mechanical and chemical treatment. A 2000mm four stand Tandem mill was installed in the first stage and
another 1420 mm five stand tandem mill was installed in the second stage. The 2000mm Tandem mill is
capable of producing finished strip thickness of 0.4 to 2 mm where as the 1420mm is intended to produce
cold rolled coils of minimum thickness up to 0.15 mm.
The product mix of Cold Rolling Mills comprise of cold rolled coils, sheets, galvanized sheets (plain and
corrugated) and tin mill black plates.
• It consists of two shops:-
 CRM 1 (reduces thickness 2-4.5mm thick into 0.63-2mm thick)
 CRM 2 (reduces thickness 1.4-2mm thick into 0.63-1.6mm thick)

4.PRODUCTS & MARKET
BSL has made significant contribution in terms of meeting domestic demand for iron & steel. Bokaro
has been able to produce special and new grades of steel for import substitution. Bokaro's pig iron,
slabs, hot rolled coils and sheets, cold rolled sheets and coils are exported to many countries.
The major products of Bokaro are pig iron, HR coils/sheets/plates, HR slit coils, CR coils/sheets, CR slit
coils, Galvanised sheets (plain & corrugated), Tin gauge black plates.
It produces special steel products like SAILCOR, SAILPROP, SAILMEDSi, SAILRIM, API grade
steel, HRNO, SAILMA, WTCR, BSL46 for auto sector etc.
Many of these products have been introduced after modernization. All the products of BSL are marketed
in India through SAIL's Central Marketing Organization (CMO).
CMO keeps in touch with the production unit as well as the transport and shipping sector. It operates
through a network of stockyards, dockyards, branch sales offices, consignment agents, extension
counters and authorized dealers. SAIL's International Trade Division looks after export of steel
products, maintaining close liaison with buyers abroad. Its products are exported to many countries.
Notable among them are .Japan, Egypt, UK, Italy, Russia, Sri Lanka, Bangladesh, Taiwan, Mayanmar
and Nepal.

5. CONCLUSION
The training at BOKARO STEEL PLANT was very helpful.
Engineering students gain theoretical knowledge through books. It is volatile and not of much use without
knowing its practical implementation.
Training is one of the important aspects for an engineering student's carrier to strengthen the practical
concepts. It was an awesome experience in training as the things we all learnt in our previous year was seen
implemented practically.
I had a chance to see the blast furnace and steel melting shop where the main working of steel plant is
being done and also I saw the working of various shops of the plant, which was very interesting. So the
training was more than hope to me and helped me to understand about power system more.

References
1. http://commonelectricaldoubts.blogspot.in/2014/08/training-report-on-bokaro-steel-plant.html
2. http://www.faadooengineers.com/threads/10243-Summer-training-at-bokaro-steel-plant
3. http://www.powershow.com/view4/63c3c8-
MGQ4Y/AN_OVERVIEW_OF_BOKARO_STEEL_PLANT_powerpoint_ppt_presentation
4. www.sail.co.in

Vocational Training in Steel Authority of India Limited (SAIL)-Bokaro Steel Plant

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