8/3/2019 Subodh Doc

1/31

ACKNOWLEDGEMENT

I am very thankful to Mr.S.S. Mohanti, Managing Director, SAIL, BOKARO for providing

me with this opportunity to work with the organization; Mr.ShankarChaudhari(GM,

HRD), Mr. S.K. Singh, Mr. Rajesh Singh, and Mr. P.K. Mishra from the training department

of HRD, SAIL, Bokaro for making all required resources available.

I would like to express my sincere thanks to all the technical experts: Mr. R.R

Kumar, Mr. A.K.Gupta, Mr.H.S Mishra, Mr.H.Nigam, Mr. R.A.P Singh, Mr. S.K Singh, Mr.

A.K Mishra, Mr. B.B.Kochgavay, Mr.K.KSrivastava, Mr.P.S Krishnamurthy who helped me

understand the various systems involved.

I would like to extend my gratitude Dr. V.I.George for his constant inspiration and

guidance. I also thank Mr. R.K.Sinha for helping the PSD for the opening of the PS station

and to all the technical experts and employees at the plant who helped us during the program.

Lastly, I would also like to thank all my PS mates for their constant support and those

involved, directly or indirectly, with me in due course of the project.

SUBODH KUMAR

ELECTRONICS & COMMUNICATION BRANCH

(08EELEC058)

8/3/2019 Subodh Doc

2/31

TABLE OF CONTENTS

2

8/3/2019 Subodh Doc

3/31

3

1. INTRODUCTION

1.1 Lay-out of Bokaro Steel Plant

2. DEPARMENTS VISITED :-

2.1 RMHP, CO AND SP

2.1.1 Raw Material Handling Plant

2.1.2Coke Ovens & By-Product Plant (CO and BPP)

2.1.3 Sintering Plant

2.2 BLAST FURNACE

2.2.1 INTRODUCTION

2.2.2 INPUTS

2.2.3 OUTPUTS

2.2.4 PROCESS REACTIONS

2.2.5 INSTRUMENTATION

2.3 STEEL MELTING SHOP-1

2.3.1 Raw Material

2.3.2 Sections

2.3.3 Instrumentation and Control

2.4 STEEL MELTING SHOP-2

2.4.1 Inputs

2.4.2 Outputs

2.4.3 Sections

2.4.4 Measurement and Control

2.5 CONTINUOUS CASTING SHOP

2.5.1 Sections

2.5.2 Measurement and Control

2.5.3 Advantages

2.6 HOT SRIP MILL

2.6.1 Instrumentation

2.6.2 Reheating Furnace

2.6.3 Mill Instrumentation

2.7 COLD ROLLING MILL

2.7.1 INPUT

2.7.2 OUTPUT

2.7.3 SECTIONS

2.7.4 ZONES

2.7.5 MEASUREMENT AND CONTROL 2.8 HOT DEEP GALVANIZING LINE

2.9 PLANT EXCHANGE

2.10 ECRS

3. RESULT

3

4

5

5

5

5

6

6

7

7

7

8

9

14

14

15

15

15

15

15

16

1617

17

18

19

20

22

22

22

23

23

23

23

24

25

25

26

26

27

28

8/3/2019 Subodh Doc

4/31

CHAPTER 1.0

INTRODUCTION

Bokaro Steel Plant is located in the Bokaro district of Jharkhand. It is the fourth integrated

public sector Steel plant in India built with Soviet help. It was incorporated as a limited

company in the year 1964. It was later merged with the state owned Steel Authority of India

Limited (SAIL).

Formerly it was known as Bokaro Steel Limited (BSL). Bokaro Steel Plant is hailed as India's

first Swadeshi Steel plant. Its first blast furnace was started on 2nd October 1972. At present

it houses five blast furnaces with total capacity to produce 4.5 MT of liquid steel. The plant is

undergoing a mass modernization drive after which its output capacity is expected to cross 10

MT. The first shop of Bokaro Steel Plant got the ISO 9001 certification way back in 1994,

and its SAIL JYOTI branded products enjoy a loyal market.

Fig.1: The entrance of Bokaro Steel Plant

4

8/3/2019 Subodh Doc

5/31

1.1 LAYOUT OF BOKARO STEEL PLANT

Fig. 2: Layout of Bokaro Steel Plant

5

8/3/2019 Subodh Doc

6/31

CHAPTER 2.0

DEPARTMENTS VISITED

2.1 RMHP,CO AND SP

2.1.1 RAW MATERIAL HANDLING PLANT

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.

Some 9 MT of different raw materials viz. Iron ore fines and lumps, Limestone (BF and

SMS grade), Dolomite lumps and chips, hard Coal and Manganese ore are handled here

every year.

Iron ore and fluxes are sourced from the captive mines of SAIL situated at Kiriburu ,

Meghahataburu, Bhawanathpur, Tulsidamar and Kuteshwar. Washed coal is supplied

from different washeries at Dugda, Kathara, Kargali and Giddi, while raw coal is

obtained from Jharia coalfields.

2.1.2 COKE OVENS AND BY-PRODUCT PLANT (CO AND BPP)

The Coke Oven Complex at Bokaro converts prime coking coal from Jharia,

Dugda and Moonidih and medium coking coal form Kargali, Kathara and Mahuda,

blended with imported coal, into high quality coke for the Blast Furnaces, recovering

valuable by-products like Anthracene Oil, Benzene, Toluene, Xylene, Light Solvent

Naphtha, Ammonium Sulphate and Extra-hard Pitch in the process. Bokaro is situatedin the prime coal belt of the country.

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

measures.

6

8/3/2019 Subodh Doc

7/31

Fig. 3:CokeOvensComplex

2.1.3SINTERINGPLANT (SP)

The sintering plant at Bokaro is unique in many respects. It has a very high sintering

area per machine, there is provision for partially cooling the sinter on machine itself, the

ignition furnace is of double hearth, plus extended hearth provision is there for adding extra

amount of coke on the top layer of the charge.

Sintering may be defined as the process where heat is produced by combustion of solid fuels

within moving beds of loosely packed particles, so as to agglomerate the loose particles i.e.

iron ore and other fines into a compact porous mass. This porous mass which is called sinter

is used in blast furnace as an iron bearing charge material. If there was no sintering plant then

the fines and the waste materials arising in the iron ore mines and steel plants would have

posed a problem regarding their disposal. So sintering plant helps in that not only it supplies a

suitable charge for blast furnace but also eliminates other intricate problems.

The set up of Sintering plant at Bokaro comprises of five main sections. They are

i. Stock bins and proportioning section

ii. Waste bin section

iii. Raw material section

iv. Machine building section

v. Slime thickening section

2.2 BLAST FURNACE

2.2.1 INTRODUCTION

7

8/3/2019 Subodh Doc

8/31

The purpose of a blast furnace is to chemically reduce and physically convert iron

oxides into liquid iron called "hot metal". The blast furnace is a huge, steel stack lined with

refractory brick, where iron ore, coke and limestone are dumped into the top, and preheated

air is blown into the bottom. The raw materials require 6 to 8 hours to descend to the bottom

of the furnace where they become the final product of liquid slag and liquid iron. These liquid

products are drained from the furnace at regular intervals. The hot air that was blown into the

bottom of the furnace ascends to the top in 6 to 8 seconds after going through numerous

chemical reactions. Once a blast furnace is started it will continuously run for four to ten

years with only short stops to perform planned maintenance.

Fig 4: Blast Furnace

2.2.2 INPUTS

Iron ore lump (Hematite (Fe2O3) or Magnetite (Fe3O4) and the iron content ranges

from 50% to 70%.)

Sinter

Metallurgical coke

Limestone

Manganese

8

8/3/2019 Subodh Doc

9/31

Nut coke /special coke

2.2.3 OUTPUTS

Hot Metal

BF gas (used as fuel)

Gangue material used in the form of slag

2.2.4 PROCESS REACTIONS

The coke descends to the bottom of the furnace to the level where the preheated air or

hot blast enters the blast furnace. The coke is ignited by this hot blast and immediately reacts

to generate heat as follows:

C + O2 = CO2 + Heat

Since the reaction takes place in the presence of excess carbon at a high temperature the

carbon dioxide is reduced to carbon monoxide as follows:

CO2+ C = 2CO

Carbon monoxide, is necessary to reduce the iron ore by series of chemical reaction:

1) 3 Fe2O3 + CO = CO2 + 2 Fe3O4 Begins at 850 F

2) Fe3O4+ CO = CO2 + 3 FeO Begins at 1100 F

3) FeO + CO => CO2 + Fe ( Begins at 1300 F)or

FeO + C => CO + Fe

The limestone descends in the blast furnace and remains a solid while going through its

first reaction as follows:

CaCO3 => CaO + CO2

9

8/3/2019 Subodh Doc

10/31

This reaction requires energy and starts at about 1600F. The CaO formed from in this reaction

is used to remove sulfur from the iron which is necessary before the hot metal becomes steel.

This sulfur removing reaction is:

FeS + CaO + C => CaS + FeO + CO

The CaS becomes part of the slag. The slag is also formed from any remaining Silica

(SiO2), Alumina (Al2O3), Magnesia (MgO) or (CaO) that entered with the iron ore,

pellets, sinter or coke. The liquid slag then trickles through the coke bed Calcia to the

bottom of the furnace where it floats on top of the liquid iron since it is less dense.

2.2.5 INSTRUMENTATION:

2.2.5.1 SENSORSThe main variables in the blast furnace which need to be sensed by the master

computer for comprehensive sensing and control are:

a) Composition.

b) Sizing or Screening.

c) Temperature.

d) Pressure.

e) Voltage (only in Electrical Generators)

f) Ampere (only in Electrical Generators)

g) Misc. Variables and Sensing.

a) Composition:

Composition analysis is one of the main mission critical variables to guarantee

troubleless BF Operation and Product Composition. In a typical steel product from a BF

operation the main critical elements are:

a. Carbon. (Fe3C, Solid Solution, Free Form)

b. Sulphur. (MnS, FeS, etc.)

c. Phosphorus. (Free Form, etc.)

d. Manganese. (Free Form, MnS)

e. Silicon. (Solid Solution, Free Form, Oxide)

10

8/3/2019 Subodh Doc

11/31

Table 1: Instrumentation used in the analysis are:

Methods Of Analysis Materials to be analyzed

Optical Emission Crude Steel ,Product

X-Ray Fluorescence Slags , sinters

Inert Gas Fusion Steels

Plasma Method Liquids

Ion Selective Electrodes Liquids

Mass Spectrometry Off-Take gases

Neutron Activation Solid steel

b) Sizing and Screening:

Sizing and screening is required at raw material input and sinter plant to let the desired

sized particles pass and reject the remaining. This can simply be achieved by using industrial

screens, which start from small diameter screens to large diameter screens in many steps,

electronic weighing machines permanently manufactured at the bottom of each screen can be

used to measure the weight retained in each screen and this data may be digitized and put to

an attached computer, which will feed the data to the master computer by LAN.

The attached computer besides sending the weights retained, can also be used to control

robotic arms to spread the particles uniformly on the screens and to

remove particles from the screen. The robotic arms can also be replaced by mechanicalcounterparts for cost reduction.

c) Temperature Measurement:

Temperature is the main mission critical variable especially in blast furnace, which should

be measured at all costs. The temperature in the blast furnace gives following information:

Extent of combustion of coke and oxygen in air.

The temperature distribution of the entire blast furnace gives an idea of the extent of

reactions and processes occuring in the furnace

The condition of the refractory bricks can be judged from the comparison of the

temperature of outer shell and internal temperature.

Numerous devices can be used to determine the temperature of various stages in steel making,

some of the most common methods are:

11

8/3/2019 Subodh Doc

12/31

i) Optical Pyrometer:

The temperature results in the emission of radiations of special wavelengths, an optical

pyrometer is device used to measure the intensity of these special radiations by

semiconductor photo sensors and display them as the temperature on the display. They

are usually gun shaped devices and can be used to measure the desired temperature

without any contact with the hot material.

ii) Thermal / IR Camera Systems:

Thermal / IR Cameras measuring light usually in 3 to 8 micrometer wavelength by a

thermally stable cooled Camera Array. It measures the near infrared light emitted from

hot objects by black-body radiation. These cameras usually contains built in computers or

external portable computers to make temperature distribution diagrams in real time and

also provide point temperatures at selected points without any physical contact. Thermal

Graphs or thermograms are usually obtained from these cameras. They are also used to

detect the thermal gaps in the furnace due to possible wear-off or damage of the furnace

linning.

iii)Thermo-couples:Thermo-couples are formed by joining two dissimilar metallic wires and measuring the

emf in the wires by keeping one joint at reference temperature and the other at

temperature to be measured. They are the most widely used temperature measurement

tools in metallurgy, due to their easy operation, high accuracy, high temperature stability

and rugged use.

Depending upon the metals used, the developed voltage increases between 7 and 75

micro-volt for each degree celcius increase in temperature. J-Thermocouple a junction

between iron and constantan is used to measure between -184 to 760 degree celcius.

iv)Semiconductor Temperature Sensors:

Semiconductor sensors like National's LM35 can be used to measure lower temperatures

in the range of - 55 to 150 degree Celsius. The voltage increases by 10mV for each

degree Celsius rise in temperature. The analog to digital converter usually of operational

amplifiers and the output of LM35 is adjusted to 0V for 0 degree Celsius. But due to their

lower temperature measuring capability they are not employed in metallurgy.

12

8/3/2019 Subodh Doc

13/31

v)Thermister and RTDs:Resistance Temperature Detectors and thermisters are also commonly used temperature

sensors. RTD's have capability to measure in the range of -250 to 850 degree Celsius.

These RTD's and Thermisters can be encapsulated in refractory bricks due to their low

cost. These bricks may be used to line the other most layer of the furnace to give precise

readings. The resistance is converted into voltage change and digitized by analog to

digital converter.

d) Pressure Measurement:

Pressure measurement of off-take gases, blast gases and internal blast furnace pressure is

very important variable.

i) Strain Gauges and Load Cells:

A strain gage is a small resistor whose value changes when its length is changed. It may

be made of thin wire, thin foil or semi-conductor material. These are used to convert

mechanical pressure gauges already installed in the Off-Take Gas Processing Plant into

analog electronic signals, which in turn are converted to digital signals by analog to

digital converter and integrated with microcontroller.

ii) Linear Variable Differential Transformers:

In this method the core of the transformer is moveable and the change in the voltage of

secondary coil is exploited to measure the temperature. A fixed voltage of known value

and 20KHz frequency is fed at primary coil as AC Excitation Signal. The secondary coils

are actually two coils and opposite ends of each are connected with each other, while the

remaining two are used as output. The output voltage is converted into digital signal by

special AC interface digitizer and is fed

to microcontroller.

iii) Potentiometers:

Potentiometers can be used with pressure guages to give a reading of pressure in a linear

change in resistance, which can be converted into digital signal by analog to digital

converter and fed to microcontroller.

e) Misc. Sensors:

13

8/3/2019 Subodh Doc

14/31

Various other sensors can be used in Steel Making to detect various variables which are

important for complete automation is used. Some of them are:

i) Height of Burden in Stack:

Height of burden in stack is an important factor and can be detected by a variety of

methods. One of the most easily and low cost method is the use of laser beam to detect

the height. The laser may enter the stack from a quartz window on one side and leave the

stack to be detected from another quartz window on the opposite side. A pulsing laser of

UV band may be employed to prevent it from being interfered by the light produced by

the heat in the stack. More than one laser beams can be provided at different heights to

enable the computers to detect exact height.

Another alternative which is less affected by the presence of dust particles is the use of

ultra-sound instead of laser. An ultra-sound transducer will send a signal from its

diaphram on the top of the stack and below the double bell loading system and receive

the sound waves after being reflected by burden surface and by noting the time taken to

return the sound waves will yield in the exact burden height. The only disadvantage is to

make an ultra-sound system stable enough to operate at 200 to 600 degree celcius.

ii)Gas flow detectors:

The velocity of the in-take gas or hot blast is an important factor and may be measured by

the introduction of a small turbine connected to a small low power generator just before

tuyers. The voltage generated by the generator may be converted into digital data by

analog to digital converter and fed to microcontroller or computer.

Table 2: Technical Data:

No. Of Blast Furnace 5

Volume Of each furnace 2000 cubic meter

Working volume 1756 cubic meter

Capacity of furnace 1756 cubic meter

No. Of stoves per furnace 30,300 square meter

Blast temperature 1100 degree Celsius

Max. Blast Pressure 3.2 Kg/square centimeter

Charging scheme BLT

Hot Metal Specification C=4-4.5%

14

8/3/2019 Subodh Doc

15/31

Si=0.6-1.2%

Mn=0.6-1.2%

P=0.25%

S=0.05%

2.3 STEEL MELTING SHOP I

Steel melting is a process of removal of impurities like Carbon, Silicon, Manganese, Sulphur

and Phosphorus from hot metal by oxidation and formation of basic slag. For this Hot metal

from BF is taken to LD converter after mixing in the mixture. Pure Oxygen is blown through

water cooled hence to remove impurities by oxidation and steel is made. Purity of Oxygen is

about 99.5%.

There are two Steel Melting shop, SMS-I and SMS-II. Three types are produced from

these shops:

Killed Steel

Semi-Killed Steel

Reamed Steel

2.3.1 RAW MATERIALS

Apart from the hot metals from BF the different raw material required for the production of

steel are:

Limestone

Dolomite

Aluminium

Ferro Alloys

15

8/3/2019 Subodh Doc

16/31

2.3.2 VARIOUS SECTIONS

Mixer

Converters

Pit Side

Teeming Bay

Stripper Yard

Waste heat Boiler

2.3.3 INSTRUMENTATION AND CONTROL

Distributed Control System(DCS) for Converters & Boilers

Vibro-feeder weighing System for weighing additives

Liquid Steel Temperature Measurement using throwaway type thermocouple

Weighing System in Mixer

Blow time control system

Waste Heat Boiler level measurement and control

Flow and pressure measurement and control of blowing oxygen

Lance height position measurement

Table 3: Technical Data

Capacity of SMS-I 2.5 MT/year

No. of LD Converters 5 (100/130 tonne each)

No. of Lances/Converter 2 each (280/320 NM3/min)O2

Oxygen Pressure 15-20 Kg/m3

16

8/3/2019 Subodh Doc

17/31

Mode Of Combustion Free combustion

2.4 STEEL MELTING SHOP -II

SMS-II differs from SMS-I because of blowing process and converter gas system. The mode

of combustion in SMS-II 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.

2.4.1 INPUTS

Hot metal from BF.

2.4.2 OUTPUTS

Semi-killed or Killed steel to continue casting m/c exclusively.

2.4.3 VARIOUS SECTIONS

Mixer: same as that of SMS-I

Two converters of suppressed combustion type

Steel refining unit

Continuous Caster: Heart of SMS-II and has following main point:

Turndish

Mould

Secondary Cooling zone

Straightening Rolls

17

8/3/2019 Subodh Doc

18/31

2.4.4 MEASURMENT AND CONTROL

PLC for realizing interlocks, monitoring various parameters and control

Lance Height Measurement

Converter Gas Analyzer for O2,CO,CO2

Liquid Steel Temperature Measurement using throwaway thermocouples

Weighing system in Mixer

Electronic Platform Weighing System for Bulk material charging and Ferro-alloy

weighing.

Waste heat boiler level measurement and control

Flow and pressure measurement and control of Blowing oxygen

Blow time control

Table 4: Highlights of Continuous Caster

Mould Straight with adjustable withdrawing

cooling

Dummy Bar System Top charging

Containment Segmental Design

Bending Continuous with 8 mm curvature

Roller Type Split DesignMetallurgical Length 29.5m

18

8/3/2019 Subodh Doc

19/31

Cooling Air mix cooling

Automation Mould level control, Turndish level

control, secondary cooling, breakout

prediction, computer aided quality

assurance, material, tracing etc.

2.5 CONTINUOUS CASTING SHOP(CCS)

The main function of Continuous Casting Shop is to produce steel slabs directly

from the molten steel coming from SMS-II and sending them to Hot Strip Mill (HSM) for hot

rolling.

2.5.1 SECTIONS

SRU

Caster

Turndish Preparation Area

Slab Area

Slab Yard

RERS(Replaceable Equipment Repair Shop)

2.5.1.1 STEEL REFINING UNIT(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

8/3/2019 Subodh Doc

20/31

dispatch CaSi/cafe wire is added to the ladle so as to reduce/eliminate Al2O3 choking at

caster.

2.5.1.2 CASTER

There are two twin stranded slab casters which can cast 940-1850 width of slab with a

thickness of 200,255&250 mm.

2.5.1.3 SLAB YARD

Mainly handles the slabs for despatch to Hot Strip Mill (HSM).

2.5.1.4 TURNDISH PREPARATION AREA

It is used to prepare the Turndishes for casting & RERS for repair of mould, Bender and

segments.

2.5.2 MEASUREMENT AND CONTROL

PLC based Mould Level measurement and control system

Breakout prediction system

PLC based water flow/air pressure measurement and control of different cooling of

different cooling zones

PLC based Level measurement of different water tanks

Steel temperature & Oxygen ppm measurement Electronic weighing system for hopper,

tundish, Turret and slab

Table 5: Technical Data

Type of Machine Low head machine with straight mould and

20

8/3/2019 Subodh Doc

21/31

segmented stranded guide

Length of Mould 900mm

Number of strands 2x2

Cooling bow radius 8m

Machine speed 0.2M/min-1.9M/min

Cooling Air/mist cooling

Casting Size:

Thickness

Width

Length

200mm,225mm,250mm

950-1850mm

9-10.5m

Others

Metallurgical Length

Dummy Bar

Cutting System

Average heat size

Tundish capacity

29.7m

Top charging

Torch cutting

302T

50T

2.5.3 ADVANTAGES

Higher Yield

Lower Energy Consumption

Lower operating costs

Elimination of primary mills

21

8/3/2019 Subodh Doc

22/31

2.6HOT STRIP MILL

Hot rolling refers to the plastic deformation of metal above re-crystallization

temperature by squeezing it between pair of roller. The HSM at Bokaro Steel Plant has

continuous 2000mm wide strip mill. This mill is design to roll thin and wide strip for used in

various industries such as wagon building, tube and pipe industries, drum manufacturing and

for use in CRM. The capacity of HSM is 4MT/year. The HSM is rolling different grade of

plain carbon and low alloy steel into strip 1.92 to 12mm thick and 910 to 1850mm wide in

coil form. The average rolling rate is 550T/Hrs.

Table 6: Slab Dimension

Thickness 170 to 230 mm

Width 910 to 1850 mm

Length 7.7 to 10.5m

Max.Weight 32T

Fig. 6: Layout

22

8/3/2019 Subodh Doc

23/31

Table 7: Coil Dimension

Strip thickness 1.5 to 16mm

Strip width 910 to 1850 mm

Coil inside dia 850 mmMax. Coil outside Dia 2300mm

Max coil weight 32T

Table 8: Comparison between Push Type and Walking Beam type Furnace

Pusher Type Walking Beam Type

Design Giproez Italimpianti

Specific heat combustion 0.50goal/T 0.315 Goal/T

Recuperator Ceramic Metallic

Air preheat Temperature 350 to 500 degree Celsius 650 degree Celsius

No. of Burners 57 156

Capacity 260 T/Hrs 300 T/Hrs

No. of skids 8 main 4 movable+4 fixed

Cooling system Evaporative cooling ECS

Thermal Efficiency 30 to 40% 55 to 65%

Availability 71% 95%

Burner Design Injection type Flat flame type

Slab movement Pushing action Walking Beam Action

Consumption of gas 108000NM3/Hrs 52000NM3/hrs

2.8.1 INSTRUMENTATION

Reheating Furnaces with ECS(3WB+1PT):

Principle function of reheating furnace is to heat the cold and hot slab to the rolling

temperature of 1250 degree Celsius.

Mill proper:

23

8/3/2019 Subodh Doc

24/31

a). Roughing Mill group

b). Finishing Mill Group

c). Coiler Area

2.8.2 REHEATING FURNACE

This comprises the following measurement & control system:

DCS system for measurement & control of Temperature of all zones

Gas & air flow

Mixed pressure control

Waste Gas pressure control

Upstream/Downstream Draft measurement & control

CV analyser for measurement of CV of mixed gas

O2 analyser for O2 at flue gas

pH &conductivity measurement in DM plant

10 level measurement & control, steam pressure& flow measurement & control in ECS.

2.8.3 MILL INSTRUMENTATION

A number of instruments are in use in Mill area for monitoring critical parameters:

Scanner for motor Bearing & winding Temperature at roughing, finishing stand,

combustion air fans, Roll cooling pumps & descaler pumps

Oil pressure, grease pressure, Oil level measurement

Water flow, pressure, level in distributed chamber, water level in elevated tank

Magnetic flow meter for measurement of water flow for interstand cooling

24

8/3/2019 Subodh Doc

25/31

Strip temperature measurement by infrared pyrometers in roughing stand, after/before

finishing stand, before coiler & laminar cooling area sec 1 & 2.

2.9 COLD ROLLING MILL

Cold Rolling 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

2.9.1 INPUTS

Coils from HSM through HRCF (Hot Rolled Coil Finishing)

2.9.2 OUTPUTS

Sheet Gauges

SAIL Auto

SAILCOR

Galvanized Sheet

Tin Mill

Black Planets(TMBP)

2.9.3 SECTIONS

Major sections of CRM complex are:

Pickling line

Tandem Mill

Annealing zone

Hood Annealing

25

8/3/2019 Subodh Doc

26/31

Continuous Annealing

Electrolytic Cleaning Line

Hot dip Galvanizing line

Continous coil Corrugation line

Galvanized sheet shearing line

2.9.4 ZONES

2.9.4.1 ZONE 1

It comprises of Pickling Line(PL-1&2),Tandem Mill(TM-1 & 2)

2.9.4.2 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

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

Slitting line no.1 &2

2.9.4.3 ZONE 3

It comprises of:

Hood Annealing 3

Electrolytic cleaning

Continuous annealing line(CAL)

Double Coil Reduction Mill(DCR)

26

8/3/2019 Subodh Doc

27/31

Shipping Bay

Hot dipping Galvanizing line(HDGL)

HDGL shipping Bay

HDGC consist of following sections:

Hot dipping galvanizing line

Continuous coil corrugation line

Galvanized sheet shearing line

2.9.5 MEASUREMENT AND CONTROL

Annealing furnace temperature control through DCS/PLC

Data Acquisition System(DAS) in Annealing#2

Hydrogen and Oxygen analyser in HDGL/CAL

Infrared pyrometers in HDGL/CAL

Measurement of Ph in block of chemical& conductivity in Galvanising line

Air Gas ratio control in Ammonia cracking unit/HD

2.10 HOT DIP GALVANIZING LINE

The Hot Dip Galvanizing Complex integrated with the CRM produces zinc-

coated Cold Rolled strips resistant to atmospheric, liquid and soil corrosion. The Continuous

27

8/3/2019 Subodh Doc

28/31

Coil Corrugation Line in the HDGC produces corrugated sheets and the Galvanized Sheet.

Shearing Line produces galvanized plain sheets for a variety of applications. The first shop of

Bokaro Steel to get the ISO-9001 certification way back in 1994, this complex has maintained

a high-standard of coating quality and its SAILJYOTI branded products enjoy a loyal market.

Hot-dip galvanizingis a form ofgalvanization. It is the process of coating Iron orSteel with a

thin Zinc layer, by passing the steel through a molten bath of zinc at a temperature of around

860 F (460 C). When exposed to the atmosphere, pure zinc reacts with oxygen to form zinc

oxide, which further reacts with carbon dioxide to form zinc carbonate, a dull grey, fairly

strong material that stops further corrosion in many circumstances, protecting the steel below

from the elements. Galvanized steel is widely used in applications where rust resistance is

needed, and can be identified by the crystallization patterning on the surface.

The unit has a huge assembly of rollers and kilometers of steel strips .The strips are first

passed through series of furnaces which are divided into 14 zones. This process is termed as

Continuous Annealing and imparts hardness to the material. Then the strip is passed through

molten zinc pot where the actual galvanization takes place. Optimum composition and

temperature has to be maintained here for proper galvanization to take place. The strips are jet

cooled and cleaned. The finished products are Rolls, Corrugated Sheets and sheet.

2.10 PLANT EXCHANGE

In the field of telecommunication, a telephone exchange or telephone

switch is a system of electronic components that connects telephone calls. It is a central

office used to house the equipments inside plant e.g.:- telephone switches, which make

telephone calls "work" in the sense of making connections and relaying the speech

information.

In plant exchange, the server needs 5/12V DC supply. There are different types of

cards, which are as follows:-

1) SSC (System Supervisory Control Card)

2) MMO (Memory Card)

3) TNS (Tone Sender Card)

28

http://en.wikipedia.org/wiki/Galvanizationhttp://en.wikipedia.org/wiki/Ironhttp://en.wikipedia.org/wiki/Steelhttp://en.wikipedia.org/wiki/Galvanizationhttp://en.wikipedia.org/wiki/Ironhttp://en.wikipedia.org/wiki/Steel

8/3/2019 Subodh Doc

29/31

4) HWIFC (High-way Interface Card)

5) POW (Power Card)

Types of tones:-

1) DT (Dial Tone)

2) BT (Busy Tone)

3) RBT (Ring Back Tone)

4) HT (Haulie Tone)

2.11 ECRS ( ELECTRONIC CARD REPAIR SHOP )

This shop is used :-

1) To test each component of the electronic cards/circuits.

2) To replace the faulted components.

3) To test the capacitors by an instrument called APPLEP.

4) To test the ICs by an software called ABI.

CHAPTER 3.0

RESULT

At SAIL, BOKARO I completed my vacational training successfully and learnt the total

procedure to manufacture the Steel.

In addition to Steel manufacturing, there I also came to know how to organize the work

and distribute the work among the workers. I visited the various shops, which are connected

to each other in the process of Steel manufacturing.

29

8/3/2019 Subodh Doc

30/31

30

8/3/2019 Subodh Doc

31/31

CHAPTER 4.0

CONCLUSION

The Vacational training at SAIL, Bokaro helped me in improving my practical knowledge and

awareness regarding Steel manufacturing to a large extent.

Here I came to know about the technology and material used in manufacturing of

Steel. Besides this, I also visualized the parts involved or equipments used in the Steel

manufacturing.

Here I learnt about how the Steel is being manufactured in different forms. At

least I could say that the training at SAIL, Bokaro is great experience for me and it really

helped me in making or developing my knowledge about Steel manufacturing.