internship report file of steelmills

8/11/2019 internship report file of steelmills

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PAKISTAN STEEL

INTERNSHIP REPPORT PREPARED BY[MANESH KUMAR & FAROOQ AHMED SHAIQ] Page 1


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The following information related to the internees who

have completed the task.

Farooq ahmed shaiq

[email protected]

Contact:+92300-9558276

Manesh Kumar

[email protected]

Contact:+92300-2737236

TECHNOLOGY:

Electronics (Automation & control)

DURATION OF INTERNSHIP:

30thof June to 25thof July

SUBMITTED TO:

Mr.Yousuf Ayoub
mailto:[email protected]:[email protected]:[email protected]:[email protected]:[email protected]:[email protected]


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ACKNOWLEDGEMENT

We are highly grateful to Allah, the Almighty, who in his infinite

capacity gave us the strength and latitude to work on this report and made

us succeed in doing so.

It has been an unforgettable experience to spend 4 weeks in Pakistans

lergest steel company Pakistan Steel Mills. By then I want to thank to Mr.Moin Aftab Shaikh

Chairman of Pakistan Steel Mills for providing us such a useful opportunity to strengthen our

skills.

We also take this opportunity to be greatly thankful to Mr. Qaiser Saleem , PEO (HRD) and Mr.

Naresh Kumar Incharge (HRD) for their consideration and supervision.

We are also thankful to Mr.Yousuf Ayoub, D.Manager (IPT) HRD and Mr. Alam Khan for their

cooperation, precious advice, encouragement and help throughout the internship, which

turned this 4 week internship into one of the pleasant experience.


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CHAPTER 1

COLD ROLLING MILLS (CRM}

1-1 Executive Summary 06

1-2 Cold Rolling Mills (CRM) 08

1-2.1 Pakistan Steel Hot And Cold Rolled Steel Plant, Pakistan 08

1-2.2 Plant Construction 08

1-3 Cold Rolling Mills Detailed Description 10

CHAPTER 2

STEEL MAKING DEPARTMENT 11

2-1 Steel Making Process In Pakistan Steel 12

2-2 Hot Metal Mixer 14

2-3 LD converter 15


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2-4 Charging Materials 16

2-5 Operation Of LD Converter 17

2-6 Primary Steel Making 19

2-6.1 Basic Oxygen Steel Making 19

2-7 Secondary Steel Making 20

2-8 HIsarna Steel Making 21

CHAPTER 3

ELECTRONICS DEVELOPMENT CELL 22

3-1 Electronics Services 21

CHAPTER 4

SINTERING PLANT 24

4-1 Sinter Plant 24

4-2 Production Unit 264-3 Charge Preparation 26

4-4 Secondary Mixing 27

4-5 Secondary Section 27

4-6 Sinter Handling 28


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Chapter 1

1-1 Executive Summary

Pakistan Steel is strategically located 40km south east of Karachi in close vicinity to portM u h a m m a d B i nQ a s i m . P a k i s t a n S t e e l i s a c o s t a l s i t e , w h i c h l i e s o n t h e

N a t i o n a l Highway and is linked to the railway network. Spread over an area of 18,600 acres

(29square miles) with 10,390 acres for the main plant, 8070 acres for the township and 200acres for the waterrese rvoi r Paki st an Ste el is Paki st an 's lar gest indust ri al compl ex , comprising component

units numbering more than 20.We specialize in the production of flat steel products including, billets, slabs,

hot rolled coils, cold rolled coils, galvanizedsheets/coils/formed sections and corrugated sheets.

We are vital to the supply of highquali ty and cost ef fect ive st ee l products to thedo mest ic mark et . Paki st an St ee l' sconstant efforts in continuous improvement and quality

management have resulted inaccreditation in ISO 9001, 14001, 17025, SA 8000 and OHSAS

18001. Pakistan steeljust deal with their dealership after verification, which are

consumers and traders.Consumers consume these products in their own use and traders use these productstoresale. Billets, Hot rolled, Cold rolled, Galvanized, Formed section, Pig iron ,

Coke ,Oxygen and nitrogen, Refractory bricks, Coal slag(by product), Boarderslag(byproduct), Granulated slag(by product).

on Ton of Steel Expandable upto 3.0 Million Ton per annum.

Main Products:Coke, Pig Iron, Billets, Cold Rolled Sheets, Hot Rolled Sheets,

Galvanized Sheets

Fig 1-1


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Organization Name Pakistan Steel Mills Corporation (PVT) LTD.

Foundation Stone Laid on 30th December, 1973

Foundation Stone Laid By Zulfiqar Ali Bhutto (Shaheed) Prime minister of Pakistan.

Location : 40 km East of Karachi

Production Capacity: 1.1 Million Ton of Steel Expandable upto 3.0 Million Ton per annum.

Main ProductCoke, Pig Iron, Billets, Cold Rolled Sheets, Hot Rolled Sheets,Galvanized Sheets.

Coke Oven & By Product Plant Coke 02 Batteries each contains 49 ovens

Sintering Plant Sinter 02 sinter Machines

Iron Making Department Pig Iron 02 Blast Furnaces

Steel Making PlantCast Bloom, Cast Billet,Cast Slab

02 L.D.Converters,

01 Bloom Caster01 Billet Caster

02 Slab Casters

Billet Mill Billets 800 mm Reversible Stand

Hot Strip Mill H.R.Coils / Plates02 Reheating Furnaces 1700 mmUniversal Stand

Cold Rolling MillC.R. Coils / Sheets,Galvanized,Coils / sheets, H.R.Sheets

Four high reversible machines 01 belltype Annealing furnace

Refractories Fireclay Bricks, Tar Bonded Dolomite Bricks

Lime rotary kilm,

hydrolic press

power press

Thermal Power Plant & Turbo

Blower StationElectricity 110 MW 3 Generators of 55 mw each

Oxygen Plant Oxygen 15,200 Nm3/hr Nitrogen 9,000 Nm3 /hr02 air compressor42,500 nm3/hr each


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1-2 COLD ROLLING MILLS (CRM):

1-2.1 PAKISTAN STEEL HOT AND COLD ROLLED STEEL

PLANT, PAKISTAN

Located some 40 kilometers to the east of Karachi, Pakistan Steel and its related

facilities are spread over an area of 18,600 acres, or about 29 square miles. The

construction of the complex involved the use of 1.29 cubic meters of concrete, 330,000tonnes of machinery, steel structure and electrical equipment, and the employment of

over 40,000 workers at the peak of construction.

In January 1971, the Governments of Pakistan and the USSR signed an agreement, the

latter undertaking to provide technological and financial assistance for the construction

of a coastal based integrated steel complex. The total capital cost of the project is

estimated at about Rs. 24.7 billion.

1-2.2 PLANT CONSTRUCTION

The construction work on the main plant was started in 1976. Among the main

complexes and units of the project, the first coke oven battery was commissioned in

April 1981, the first blast furnace in August 1981, the billet mill in October 1982, and the

two converters, one bloom caster and two slab casters of the steel making plant

between December 1982 and November 1983. The hot strip mill was commissioned in

December 1983, the second blast furnace in August 1984, the cold rolling mill in

December 1984, the second coke oven battery in May 1985 and the expansion projectbillet caster in November 1989.


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1-3 COLD ROLLING MILL(CRM)

The cold rolling mill is a cold reversible mill with 200,000 tonnes capacity, from which

10,000 tonnes are turned into cold formed sections. The cold rolling mill operates on hot

rolled sheets and coils produced at the hot strip mill. Cold rolled sheets are used for the

production of enameled wares, bicycles, steel fabrication, steel containers, drums,

barrels, jerry-cans, vehicle and bus bodies, steel furniture, machinery parts, products

and appliances, oil and gas appliances etc. Cold rolled sheets are also used for the

production of galvanized sheets, and black plates and tinplates.

Fig 1-3

Galvanized sheets are used for containers, trunks, boxes, packets, steel shuttering,

desert coolers, construction and roofing, ducting equipment, appliances, paneling,utensils, air-conditioners, water heaters and fresh water tanks.

Cold and hot-formed sections are used for steel fabrications, furniture, vehicle and bus

bodies, building construction, miscellaneous machinery and equipment/parts, steel

doors and windows.


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Fig 1-3 (a)

Fig 1-3 (b)


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Chapter 2

STEEL MAKING DEPARTMENT (SMD)

Steelmakingis the process for producingsteel from iron and ferrous scrap. In steelmaking,

impurities such asnitrogen,silicon,phosphorus,and excesscarbon are removed from theraw

iron,and alloying elements such asmanganese,nickel,chromium andvanadium are added to

produce different grades of steel. Limiting dissolved gases such asnitrogen andoxygen,and

entrained impurities (termed "inclusions") in the steel is also important to ensure the quality of

the products cast from the liquid steel.

[1]

There are two major processes for making steel,namelybasic oxygen steelmaking which has liquid pig-iron from the blast furnace and scrap

steel as the main feed materials, andelectric arc furnace (EAF) steelmaking which uses scrap

steel ordirect reduced iron (DRI) as the main feed materials. Oxygen steelmaking is fuelled

predominantly by the exothermic nature of the reactions inside the vessel where as in EAF

steelmaking, electrical energy is used to melt the solid scrap and/or DRI materials. In recent

times, EAF steelmaking technology has evolved closer to oxygen steelmaking as more chemical

energy is introduced into the process.
http://en.wikipedia.org/wiki/Steelhttp://en.wikipedia.org/wiki/Nitrogenhttp://en.wikipedia.org/wiki/Siliconhttp://en.wikipedia.org/wiki/Phosphorushttp://en.wikipedia.org/wiki/Carbonhttp://en.wikipedia.org/wiki/Pig_ironhttp://en.wikipedia.org/wiki/Pig_ironhttp://en.wikipedia.org/wiki/Manganesehttp://en.wikipedia.org/wiki/Nickelhttp://en.wikipedia.org/wiki/Chromiumhttp://en.wikipedia.org/wiki/Vanadiumhttp://en.wikipedia.org/wiki/Nitrogenhttp://en.wikipedia.org/wiki/Oxygenhttp://en.wikipedia.org/wiki/Steelmaking#cite_note-1http://en.wikipedia.org/wiki/Steelmaking#cite_note-1http://en.wikipedia.org/wiki/Steelmaking#cite_note-1http://en.wikipedia.org/wiki/Basic_oxygen_steelmakinghttp://en.wikipedia.org/wiki/Electric_arc_furnacehttp://en.wikipedia.org/wiki/Direct_reduced_ironhttp://en.wikipedia.org/wiki/Direct_reduced_ironhttp://en.wikipedia.org/wiki/Electric_arc_furnacehttp://en.wikipedia.org/wiki/Basic_oxygen_steelmakinghttp://en.wikipedia.org/wiki/Steelmaking#cite_note-1http://en.wikipedia.org/wiki/Oxygenhttp://en.wikipedia.org/wiki/Nitrogenhttp://en.wikipedia.org/wiki/Vanadiumhttp://en.wikipedia.org/wiki/Chromiumhttp://en.wikipedia.org/wiki/Nickelhttp://en.wikipedia.org/wiki/Manganesehttp://en.wikipedia.org/wiki/Pig_ironhttp://en.wikipedia.org/wiki/Pig_ironhttp://en.wikipedia.org/wiki/Carbonhttp://en.wikipedia.org/wiki/Phosphorushttp://en.wikipedia.org/wiki/Siliconhttp://en.wikipedia.org/wiki/Nitrogenhttp://en.wikipedia.org/wiki/Steel


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Fig 2-1

Steel making department

Steel making department is one of the most important departments of Pakistan steel mill. In thesedepartment can produce 1.1 million tons steel in form of cast slab, bloom and cast billet.

Basic operation of steel making department is to convert hot metal into liquid steel by oxygen

blowing and continuous casting of liquid steel in the form of slab, bloom and billets.

2-1 STEEL MAKING PROCESS IN PAKISTAN STEEL:-

The charging material is charged into the vessel by tilting the vessel. After charging, vessel is

located it position. Lancing is started. The oxygen blowing is continued for 18 minutes. The

blowing has three phases; each phase consists of 6 minutes. In the first phase of six minutes pig

iron deoxidizes and removes the silicon impurity.


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In the second phase of six minute other impurities are oxidizes such as sulphur, phosphorous,

manganese etc. In the last phase of blowing the temperature is maintained according to the

requirement. After completion of this conversion process from pig iron to steel, the vessel istilted and molten steel is tilted into the steel ladle. In ladle some alloying elements are added

according to demand and mixed by the nitrogen purging.

This purged molten metal is ready to send directly to the mold for casting. A sketch of LD

process is given below.

fig 2-1 (b)

The molten steel is pored into the mold in order to produce slab, billets and bloom. Some

technical parameters so these casting machines are given a under.

Low %C 0.350.65

Medium % 0.650.75

High %C 0.751.25


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No. of machines ONE TWO ONE

Type of machine Radial Radial/ curvilinear Radial

No. of strands Four Two Six

Profile size 260 260 W= 10001550

Metallurgical length 22meter 24meter 15.8meter

Casting speed 0.7 M/min 0.7 M/min 1.5 M/min

Steel Ladle 130 ton

dolomite lining Life AVG

30 Heats

Tundish capacity 15 ton 5 ton 12 ton

2-2 HOT METAL MIXER:-

Molten pig iron coming from the iron making department is received by hot metal mixer.

The mixer has a capacity of 1300 tons with inner volume approximately 285 m.

The temperature of hot metal is near about 1320 C with the chemical composition as

Carbon not less than 4%

S : 0.04% max

Si : 0.40.8%

P : 0.2% max

Mn : 0.51.0%

Safety lining of mixer vessel is of fireclay and working lining is made of magnesite. The lining

life of mixer vessel is about 0.8 million ton hot metal cycling.


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2-3 LD CONVERTER:

LD converter is used to convert the pig iron into steel. There are two LD converts in steel

making department. Each has metal charging capacity about 130 tons. The converter has height

to diameter ration approximately 1:37. The tap to tap time is 55 minutes.

Fig 2-3

The LD converter is top oxygen blown converter. Oxygen is delivered by the oxygen lance.

Oxygen reacts with unwanted materials and oxides form the top of the vessel. The oxygen flowrate is 30045 M/min. the safety lining of LD vessel is chrome magnesite whereas tar bonded

dolomite is used as a working lining refractory. Production rate of each converter is about

27heats per day. In these figure below showing oxygen lacing

When iron is produced from the ore in a blast furnace, it is rich in carbon and also contains many

impurities. It then has to be converted into steel which has controlled quantities of carbon andmuch reduced concentrations of impurities.


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Fig 2-3 (b)

Bessemer realized that forcing air through molten steel would oxidize impurities in the pig ironand raise the metal temperature without the need for additional fuel, i.e.,`The manufacture of

malleable iron and steel without fuel'.

His invention nearly failed in that some of the iron ores used by those who applied the idea foundthe iron to contain larger quantities of sulphur and phosphorus, leading to very poor properties.

However, this was solved by adding ferromanganese to the melt.

The nitrogen concentration of steel produced using the Bessemer process tended to be greaterthan desirable because of the use of air (which is mostly nitrogen).

Fig 2-3


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This problem was solved in the Linz-Donawitz process (Lenz and Donowitz are both parts of

Austria). In this, high-pressure oxygen is blown at the molten pig iron using a water-cooled

lance. A slag of lime and dolomite is used. The process is fast because of the use ofcommercially pure oxygen, and generates large quantities of heat which can be exploited to add

scrap steel to the melt. The basic nature of the flux helps remove phosphorus so there is a greatertolerance to the raw materials used in the process.

2-4 CHARGING MATERIALS:-

LD converter has capacity of charge 130tons. Detail of input material description given as under.

Hot metal Basic raw material

Steel scrap Coolant

Iron ore Coolant

Oxygen gas for blowing

Lime Fluxing material

Calcium fluoride Slag forming material

Aluminum Deoxidizer

FeAlloys alloying of steel

Charging of LD vessel

2-5 OPERATION OF LD PROCESS:-1. Molten iron from ablast furnace is poured into a largerefractory-lined container called a

ladle;

2. The metal in the ladle is sent directly for basic oxygen steelmaking or to a pretreatmentstage. Pretreatment of the blast furnace metal is used to reduce the refining load ofsulfur,

silicon,andphosphorus.In desulfurising pre treatment, alance is lowered into the molten
http://en.wikipedia.org/wiki/Blast_furnacehttp://en.wikipedia.org/wiki/Refractoryhttp://en.wikipedia.org/wiki/Ladle_%28metallurgy%29http://en.wikipedia.org/wiki/Sulfurhttp://en.wikipedia.org/wiki/Siliconhttp://en.wikipedia.org/wiki/Phosphorushttp://en.wikipedia.org/w/index.php?title=Lance_%28metallurgy%29&action=edit&redlink=1http://en.wikipedia.org/w/index.php?title=Lance_%28metallurgy%29&action=edit&redlink=1http://en.wikipedia.org/wiki/Phosphorushttp://en.wikipedia.org/wiki/Siliconhttp://en.wikipedia.org/wiki/Sulfurhttp://en.wikipedia.org/wiki/Ladle_%28metallurgy%29http://en.wikipedia.org/wiki/Refractoryhttp://en.wikipedia.org/wiki/Blast_furnace


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iron in the ladle and several hundred kilograms of powderedmagnesium are added.

Sulfur impurities are reduced tomagnesium sulfide in a violentexothermic reaction. The

sulfide is then raked off. Similar pretreatment is possible for desiliconisation anddephosphorisation usingmill scale (iron oxide) and lime as reagents. The decision to

pretreat depends on the quality of the blast furnace metal and the required final quality ofthe BOS steel.

3. Filling thefurnace with the ingredients is called charging. The BOS process is

autogenously: the required thermal energy is produced during the process. Maintaining

the proper charge balance, the ratio of hot metal to scrap, is therefore very important.

The BOS vessel is one-fifth filled with steel scrap. Molteniron from the ladle is added as

required by the charge balance. A typical chemistry of hot metal charged into the BOS

vessel is: 4% C, 0.2-0.8% Si, 0.08%-0.18% P, and 0.01-0.04% S.

4. The vessel is then set upright and a water-cooled lance is lowered down into it. The lance

blows 99% pureoxygen onto the steel and iron, igniting the carbon dissolved in the steel

and burning it to formcarbon monoxide andcarbon dioxide,causing the temperature to

rise to about 1700C. This melts the scrap, lowers thecarbon content of the molten ironand helps remove unwantedchemical elements.It is this use of oxygen instead of air that

improves upon theBessemer process,for the nitrogen (and other gases) in air do not react

with the charge as oxygen does. High purityoxygen is blown into the furnace or BOS

vessel through a vertically oriented water-cooled lance with velocities faster than Mach 1.5. Fluxes (burntlime ordolomite)are fed into the vessel to formslag which absorbs

impurities of the steelmaking process. During blowing the metal in the vessel forms anemulsion with the slag, facilitating the refining process. Near the end of the blowingcycle, which takes about 20 minutes, the temperature is measured and samples are taken.

The samples are tested and a computer analysis of the steel given within six minutes. A

typical chemistry of the blown metal is 0.3-0.6% C, 0.05-0.1% Mn, 0.01-0.03% Si, 0.01-0.03% S and P.

6. The BOS vessel is tilted again and the steel is poured into a giantladle.This process is

called tappingthe steel. The steel is further refined in the ladle furnace, by adding

alloying materials to give the steel special properties required by the customer.

Sometimesargon ornitrogen gas is bubbled into the ladle to make sure the alloys mix

correctly. The steel now contains 0.1-1% carbon. The more carbon in the steel, the harderit is, but it is also more brittle and less flexible.

7. After the steel is removed from the BOS vessel, the slag, filled with impurities, is poured

off and cooled.
http://en.wikipedia.org/wiki/Ironhttp://en.wikipedia.org/wiki/Magnesiumhttp://en.wikipedia.org/wiki/Magnesium_sulfidehttp://en.wikipedia.org/wiki/Exothermichttp://en.wikipedia.org/wiki/Mill_scalehttp://en.wikipedia.org/wiki/Furnacehttp://en.wikipedia.org/wiki/Ironhttp://en.wikipedia.org/wiki/Oxygenhttp://en.wikipedia.org/wiki/Carbon_monoxidehttp://en.wikipedia.org/wiki/Carbon_dioxidehttp://en.wikipedia.org/wiki/Carbonhttp://en.wikipedia.org/wiki/Chemical_elementhttp://en.wikipedia.org/wiki/Bessemer_processhttp://en.wikipedia.org/wiki/Oxygenhttp://en.wikipedia.org/wiki/Flux_%28metallurgy%29http://en.wikipedia.org/wiki/Lime_%28mineral%29http://en.wikipedia.org/wiki/Dolomitehttp://en.wikipedia.org/wiki/Slaghttp://en.wikipedia.org/wiki/Ladle_%28metallurgy%29http://en.wikipedia.org/wiki/Alloyhttp://en.wikipedia.org/wiki/Argonhttp://en.wikipedia.org/wiki/Nitrogenhttp://en.wikipedia.org/wiki/Nitrogenhttp://en.wikipedia.org/wiki/Argonhttp://en.wikipedia.org/wiki/Alloyhttp://en.wikipedia.org/wiki/Ladle_%28metallurgy%29http://en.wikipedia.org/wiki/Slaghttp://en.wikipedia.org/wiki/Dolomitehttp://en.wikipedia.org/wiki/Lime_%28mineral%29http://en.wikipedia.org/wiki/Flux_%28metallurgy%29http://en.wikipedia.org/wiki/Oxygenhttp://en.wikipedia.org/wiki/Bessemer_processhttp://en.wikipedia.org/wiki/Chemical_elementhttp://en.wikipedia.org/wiki/Carbonhttp://en.wikipedia.org/wiki/Carbon_dioxidehttp://en.wikipedia.org/wiki/Carbon_monoxidehttp://en.wikipedia.org/wiki/Oxygenhttp://en.wikipedia.org/wiki/Ironhttp://en.wikipedia.org/wiki/Furnacehttp://en.wikipedia.org/wiki/Mill_scalehttp://en.wikipedia.org/wiki/Exothermichttp://en.wikipedia.org/wiki/Magnesium_sulfidehttp://en.wikipedia.org/wiki/Magnesiumhttp://en.wikipedia.org/wiki/Iron


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2-6 PRIMARY STEELMAKING

2-6.1 Basic oxygen steelmaking

Basic oxygen steelmaking is a method of primary steelmaking in which carbon-rich moltenpig

iron is made into steel. Blowing oxygen through molten pig iron lowers the carbon content of the

alloy and changes it into steel. The process is known as basicdue to the chemical nature of therefractoriescalcium oxide andmagnesium oxidethat line the vessel to withstand the high

temperature and corrosive nature of the molten metal andslag in the vessel. Theslag chemistry

of the process is also controlled to ensure that impurities such as silicon and phosphorus areremoved from the metal.

Fig 2-5

The process was developed in 1948 byRobert Durrer and commercialized in 195253 by

AustrianVOEST and AMG.The LD converter, named after the Austrian towns ofLinz and

Donawitz (a district ofLeoben)is a refined version of theBessemer converter where blowing ofair is replaced with blowingoxygen.It reduced capital cost of the plants, time of smelting, and

increased labor productivity. Between 1920 and 2000, labor requirements in the industry

decreased by a factor of 1,000, from more than 3 worker-hours per tonne to just 0.003. The vast

majority of steel manufactured in the world is produced using the basic oxygen furnace; in 2011,

it accounted for 70% of global steel output. Modern furnaces will take a charge of iron of up to
http://en.wikipedia.org/wiki/Basic_oxygen_steelmakinghttp://en.wikipedia.org/wiki/Pig_ironhttp://en.wikipedia.org/wiki/Pig_ironhttp://en.wikipedia.org/wiki/Alloyhttp://en.wikipedia.org/wiki/Refractoryhttp://en.wikipedia.org/wiki/Calcium_oxidehttp://en.wikipedia.org/wiki/Magnesium_oxidehttp://en.wikipedia.org/wiki/Slaghttp://en.wikipedia.org/w/index.php?title=Slag_chemistry&action=edit&redlink=1http://en.wikipedia.org/wiki/Robert_Durrerhttp://en.wikipedia.org/wiki/Voestalpinehttp://en.wikipedia.org/wiki/Linzhttp://en.wikipedia.org/wiki/Leobenhttp://en.wikipedia.org/wiki/Bessemer_converterhttp://en.wikipedia.org/wiki/Oxygenhttp://en.wikipedia.org/wiki/Oxygenhttp://en.wikipedia.org/wiki/Bessemer_converterhttp://en.wikipedia.org/wiki/Leobenhttp://en.wikipedia.org/wiki/Linzhttp://en.wikipedia.org/wiki/Voestalpinehttp://en.wikipedia.org/wiki/Robert_Durrerhttp://en.wikipedia.org/w/index.php?title=Slag_chemistry&action=edit&redlink=1http://en.wikipedia.org/wiki/Slaghttp://en.wikipedia.org/wiki/Magnesium_oxidehttp://en.wikipedia.org/wiki/Calcium_oxidehttp://en.wikipedia.org/wiki/Refractoryhttp://en.wikipedia.org/wiki/Alloyhttp://en.wikipedia.org/wiki/Pig_ironhttp://en.wikipedia.org/wiki/Pig_ironhttp://en.wikipedia.org/wiki/Basic_oxygen_steelmaking


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350 tons and convert it into steel in less than 40 minutes, compared to 1012 hours in anopenhearth furnace

Electric arc furnace steelmaking is the manufacture of steel from scrap or direct reduced ironmelted by electric arcs. In an electric arc furnace, a batch of steel ("heat") may be started by

loading scrap or direct reduced iron into the furnace, sometimes with a "hot heel" (molten steel

from a previous heat). Gas burners may be used to assist with the melt down of the scrap pile in

the furnace. As in basic oxygen steelmaking, fluxes are also added to protect the lining of thevessel and help improve the removal of impurities. Electric arc furnace steelmaking typically

uses furnaces of capacity around 100 tonnes that produce steel every 40 to 50 minutes for furtherprocessing.

By-product gases from the steel making process can be used to generate electricity through theuse of reciprocating gas engines.

2-7 SECONDARY STEELMAKING:

Secondary steelmaking is most commonly performed in ladles and often referred to as ladle

(metallurgy).Some of the operations performed in ladles include de-oxidation (or "killing"),

vacuum degassing, alloy addition, inclusion removal, inclusion chemistry modification, de-

sulphurisation and homogenisation. It is now common to perform ladle metallurgical operationsin gas stirred ladles with electric arc heating in the lid of the furnace. Tight control of ladle

metallurgy is associated with producing high grades of steel in which the tolerances in chemistryand consistency are narrow.

Fig 2-6
http://en.wikipedia.org/wiki/Open_hearth_furnacehttp://en.wikipedia.org/wiki/Open_hearth_furnacehttp://en.wikipedia.org/wiki/Electric_arc_furnacehttp://en.wikipedia.org/wiki/Ladle_%28metallurgy%29http://en.wikipedia.org/wiki/Ladle_%28metallurgy%29http://en.wikipedia.org/wiki/Ladle_%28metallurgy%29http://en.wikipedia.org/wiki/Ladle_%28metallurgy%29http://en.wikipedia.org/wiki/Electric_arc_furnacehttp://en.wikipedia.org/wiki/Open_hearth_furnacehttp://en.wikipedia.org/wiki/Open_hearth_furnace


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2-8 HISARNA STEEL MAKING:

The HIsarna steelmaking process is a process for primary steelmaking in which iron ore isprocessed almost directly into steel. The process is based around a new type of blast furnacecalled a Cyclone Converter Furnace, which makes it possible to skip the process of

manufacturing pig iron pellets that is necessary for thebasic oxygen steelmakingprocess.

Without the necessity for this preparatory step the HIsarna process is more energy-efficient andhas a lowercarbon footprint than traditional steelmaking processes.

Fig 2-7
http://en.wikipedia.org/wiki/Basic_oxygen_steelmakinghttp://en.wikipedia.org/wiki/Carbon_footprinthttp://en.wikipedia.org/wiki/Carbon_footprinthttp://en.wikipedia.org/wiki/Basic_oxygen_steelmaking


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Chapter 3

ELECTRONIC DEVELOPMENT CELL( EDC)

3-1 Electronics Services

Electronic Development Cell of Pakistan Steel is engaged in designing and development of

indigenous electronic instruments/systems by employing modern micro-controller based digitalelectronics for the replacement of outdated/obsolete

equipment and for enhancement of existinginstrumentation and automation of various productionunits.

Electronics design engineers in EDC have ability of

programming in low level (Assembly language) and high

level programming languages and designing hardware

based on micro-controllers and digital electronics which

are the basis of all new instrumentation and automation such as PLCs, DCS, and HybridControllers.

In last two decades EDC has designed and installed more than 200 instruments at various

complexes of Pakistan Steel. These instruments are working round the clock for themeasurements of industrial parameters which includes :

1. Temperature Instruments (Indicators &Controllers for various furnaces)

2. Flow Indicators (For the measurement of Gas,Liquid and Steam)

3. Batch/Hopper Weighing (For the preparation of

blend of different materials, Measuring capacity

depends on silos or weighing hoppers)

4. Conveyor Belt Weighing Scales (Online weighing of raw materials transported throughconveyor belts. Maximum weighing capacity is 1000 tones/hours.)


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5. Weighing platform Scales (These are portable weighing platforms easily moved or installedany where. These are used for weighing of finished product upto 15 tones)

6. Process Control Instruments (Like length/speed/width measuring, sheet centering, sheetdetection, coil diameter measuring, level measurements, jumbo process data display, panelmeters etc.)

7. Jumbo Clock (14X4.5 Feet) for Main Gate Entrance Our strong area of specialty is to meet

customer requirements of plant In the field of instrumentation & automation. We can design &

develop electronic instruments to meet specific requirements of process for Which

instruments are not readily available in markets. Further, we have also developed expertise inthe below mentioned areas :

EDC can design and develop functionallyequivalent, electronic cards for the replacement of

irreparable electronic cards of various process

machines to keep machines and process in operation.

EDC can design and develop electronic cards

required for interfacing latest sensors/transducers with

legacy systems and interfacing of old sensors to latestinstruments.

Designing of artwork for single and double sided PCBs (Printer Circuits Boards).

We may extend our skills and expertise for the preparation/vetting of technicalspecifications of electronic instruments/equipments required for the procurement from local or

foreign agencies.

EDC is fully capable of implementing new technologies emerging in the field of

automation and instrumentation. We can provide consultancy for selecting and configuring awide array of available instruments according to process requirements.

After obtaining ample experience of designing and development of electronic equipment, we are

now in position to extend our expertise and service through this letter to develop bidirectional

relationship for resolving problems and helping you in the field of instrumentation and

electronics technology. We will very much appreciate your interest and enquiries in the specificareas of your interest.


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Chapter 4

SINTERING PLANT

Sintering Department is one of the most important departments of Pakistan Steel Mill it is

designed for the production of sinter, with facilities for supply to the blast furnace for productionof pig iron.

The annual demand of sinter is estimated as 56, 000, 0 tons per annum.

4-1 SINTER PLANT:-

The function of the Sinter Plant is to supply the blast furnaces with sinter, a combination of

blended ores, fluxes and coke which is partially cooked or sintered. In this form, the materials

combine efficiently in the blast furnace and allow for more consistent and controllable iron

manufacture. Figure 1 shows a simplified diagram of a sinter plant.

Materials enter the sinter plant from storage bins. They are mixed in the correct proportions

using weigh hoppers, one per storage bin, except for the return fines for which an impact meter isused instead. Weighing is continuous, as is the whole sintering process. The weighed materials

pass along a conveyor to the mixing drum where water is added either manually or as a

calculated percentage of the weight of material entering the drum.

Fig 4-1


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The moisture content of the coke is measured in the strand roll feed hopper and used to trim the

secondary water flow rate. The mix permeability is also measured and used to modify the

amount of water required.

The mix material is fed onto the strand from the hopper by a roll feeder. The bed depth is set and

kept constant by adjusting the cut-off plate which is fitted with probes to sense the depth of

material and automatically vary the roll feeder speed. The quantity of material in the feed hopper

itself is held constant by automatic adjustment of the feed rates from the individual raw materialbins.

Figure 4-1 (b) Simplified diagram of a sinter plant of Pakistan steel


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4-2 PRODUCTION UNIT:-

Sintering plant is mainly composed of following production unit.

Charge preparation

Primary mixing

Secondary mixing

Sintering section

4-3 CHARGE PREPARATION:-

The various substances are first mixed like calcium carbonate, manganese ore, dolomite, raw

silica sand and if desired granulated.

These raw materials in obtained from 12 bunkers which are sided in 2 rows. Each bunker contain

different materials for charge preparation The required size for flux and dolomite is about 0-

50mm which is screened form used for charge preparation. The required size for fuel grinding is

about 0-25mm for sintering of charge preparation. The iron ore required for charge preparation isabout 0-6mm size and these same conditions is also for manganese ore for charge preparation.

Iron ores are agglomerated on the conveyor belts consist of a large number of wagons. These

wagons that have been linked up as an endless conveyor belt which can be as big as 4 m in width

and 100 m in length. The fine ore to be sintered is moistened and fed on to the circulating grid

together with coke slack and additions such as limestone, quick lime, olivine or dolomite.


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Primary Mixing:-

The amount of primary water added is about 4-5% proportional to the weight of raw mixentering the mixing drum.

Fig 4-2

4-4 SECONDARY MIXING:-

The secondary water addition is about 2-3% setpoint is frequently taken as a proportion of the

raw mix belt weighed PV. For greater accuracy, the moisture meter reading is used to trim

the material/water ratio. This corrects the water flow rate according to the measured moisture

content of the raw mix.

Cascade control is not always used but since the water flow loop responds faster than the

moisture loop it does produce better results. Then it is passes through the shuttle conveyors into

the hopper. Then after the hopper it drops into the balling drum for frequent mixing is allowedfor 1-2 hours.

4-5 SINTERING SECTION:-

The materials from the baling drum are passed through in to sintering section. Burners above a

heat-resistant grate belt heat the material to the required temperature (1100-1200 C). In the


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sintering machine 92 pellet car are used. In Pakistan steel 2 sintering machine are available but

nowadays only one sintering machine is working

Fig 4-4 (a)

fig 4-4 (b)

This causes the fuel in the mixture to be ignited. The carbon burns with the aid of the air sucked

through the grid into the mixture by means of 8 blower fans at the bottom of sintering machine.

Resulting in the flame front being moved through the sintering bed. The sintering processes are


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completed once the flame front has passed through the entire mixed layer and all fuel has been

burnt.

Chlorine compounds can enter into the sinter installation by means of the additive cokes

The raw mix is ignited by the ignition hood, which is fuelled by a mixture of coke oven gas, blast

furnace gas and sometimes natural gas. The calorific value of the mixture and the set hoodtemperature are controlled. A separate control system is provided to maintain a fixed hood

pressure by adjusting the wind box dampers immediately under the ignition hood.

Fig 4-4

The sinter strand is a moving conveyor of hot sinter, which continues to cook after leaving the

hood, where air is pulled from the sinter by a strand draught fan.

An important part of the sintering process is burn-through. This is where the sinter layer has

completely burned through its section and is detected by temperature probes under the sinter bed.Burn through should be achieved but must not occur too soon after the ignition hood. The

draught on the strand is maintained at a preset value by controlling the main fan louvers from

pressure measurements in the wind main. This governs the point at which burn through occurs.

4-6 SINTER HANDLING:-

After the end of the strand, the sinter passes through a spiked roll crusher and the hot screens to

the rotating circular cooler. A number of fans are usually used for cooling, and the speed of the

cooler is determined by:


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Strand speed

Bed depth

The fines removed by the hot screens of -8mm size are conveyed to the return fines bin. After

cooling, the sinter is passed into the discharge bunker. At this stage, the level is controlled by

varying the outlet feed rate (usually vibros).

The sinter then passes to the cold screening area, where it is passed through crushers and screens

to produce particles in a specific size range. Sinter below the required size passes over a belt

weigher and returns with the hot fines to the return fines bin.

The difference between the weight of the cold fines, and the weight of the total fines produced,

gives a measure of the hot fines. The following factors can affect the rate at which fines areproduced:

Mix control

Particle size

Chemistry

Weight

Moisture content

Bed depth

Ignition hood temperature and pressure

Warm screens

Two important properties of sinter are basicity, which is controlled by the amount of limestone,

and strength, which is controlled by coke content.

The sinter is passes through conveyor belt which is then screened up to +20mm size which is

used suitable for use in the blast furnace. Conveyors transport the material to the blast furnacestock house, where it is added to other materials to form the blast furnace burden. The sinter

which is screened up to -20mm size is return to the sinter plant.

internship report file of steelmills

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