STEEL

By

L-001-PARTH ADHIYA

Contents

Steel

History of Steel

Properties of Steel

Major consumers of Steel in the world

Stainless Steel

Health & Safety

Manufacturing Process

Economics

07-Jun-152

Steel

Steel is generic name for a group of ferrous metalscomposed principally of iron

It is the most useful metallic material known onaccount of abundance, durability, versatility, andlow cost

It is used in the form of bars, plates, sheets,structural shapes, wire pipe tubing, forging andcastings

History

History of steel can be traced back to the iron age.

Steel is stronger and harder than bronze thus usedto manufacture weapons and tools.

By 17th century irons properties were wellunderstood and used widely in Europe.

In 1856, Henry Bessemer developed an effectiveway of using oxygen to reduce carbon content insteel.

History of Steel In India

India is the 4th largest steel producer in the world.

Modern iron and steel industry in India owes its origin to JamsetjiNusserwanji Tata.

Tata Iron and Steel (TISCO) started its production in 1907 and by 1939 itbecame the largest steel producer in the British empire.

Under the stewardship of the then Prime Minister Shri Jawaharlal Nehru,the Indian steel industry expanded and the first government steel company,Hindustan Steel Limited was started which set up 3 plants in India

In 2006, Mittal steel, founded by Laxmi Mittal acquired Arcelor for$34.3billion to become the worlds biggest steel maker, ArcelorMittal. Itcontrols 10% of the worlds output

In Jan 2007, India's TISCO acquired $11.3 billion offer to buy European steelmaker Corus Group.

Properties of different types of Steel

Major consumers of Steel in the world

Stainless steel

Stainless steel generally contain between 10-20% chromium as the main alloying elementand are valued for high corrosion resistance.With over 11% chromium, steel is about 200times more resistant to corrosion than mildsteel.

Stainless Steel Grade316

CHEMICAL FORMULA

Fe,

Chemical properties of Stainless Steel Grade316 Subject to pitting and crevice corrosion in warm chloride

environments, stress corrosion cracking above about60C.

Considered resistant to potable water with up to about1000mg/L chlorides at ambient temperatures, reducingto about 500mg/L at 60C.

Good oxidation resistance in intermittent service to870C and in continuous service to 925C. It is moreresistant to carbide precipitation

316 is usually regarded as the standard marine gradestainless steel, but it is not resistant to warm sea water

Cannot be hardened by heat treatment Excellent weldability by all standard fusion and

resistance methods, both with and without filler metals.

Stainless steel 316

Applications Food preparation equipment particularly in

chloride environments

Pharmaceuticals

Marine applications

Architectural applications

Medical implants, including pins, screws and orthopaedic implants like total hip and knee replacements

Fasteners

Accidents, Health & Safety

Accidents: Due to massive equipment size, hightemperatures, and moving objects there is a highpossibility for accidents to occur therefore safety hasbecome a priority and is a direct responsibility ofplant superintendent.

Health hazards: Radiant energy Noise Exposure to gases like carbon monoxide

Prevention : protective masks , eye shields & earprotection

Steel Price trend

Revenue trend of steel from major players

SAIL - Steel Authority of India Limited, a PSU

TSL - Tata Steel Limited ( TISCO)

RINL - RashtriyaIspat Nigam Limited, a PSU

JSW - is one of the lowest cost steel producer in the world

Jindal Steel - is largest stainless steel producer in the world

Steel producers

Various Manufacturing Processes

Blast Furnace Steelmaking

Electric Arc Furnace Steelmaking (EAF)

Basic Oxygen Steelmaking(BOS)

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Criteria Blast Furnace EAF BOS Best Process

Thermodynamic Feasibility

1200-2000C or above

1800C 1700C- 2000C EAF

Economic Cost Very High Economically Very Feasible

Moderate EAF

Raw Material Availability

Easily Available Easily Available, Flexibility in Raw Material

Alloy Has to be produced, Rest Available

EAF

Yield and Conversion Very High Moderate Very High Blast Furnace

Process Condition Extreme Moderate Moderate EAF, BOS

Safety Aspects High Moderate Moderate EAF, BOS

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Best Process Selection

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Benefits Of EAF Process :Increased productivity due to shortest melting and idle times.High flexibility of charge materials.Low tapping temperatures and minimum slag carryovers.Low Power ConsumptionEconomically feasible than Blast furnace process and BOS.

Electric Arc Furnace

Raw Materials Used :- Iron Ore, Steel Scrap, Lime

Process Conditions : Scrap should be pre-heated upto 600 Melting Power 125- 130 MW Temperature goes upto 1700

Consumption Values : Electricity : 340 kWh/t Electrodes : 1.2 kg/t Carbon injected : 7kg/t Temperature : 1100 - 1800C

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Construction :

A direct arc furnace consists of heavy steel shell lined with refractory brick, silica for and lined furnace and magnezite for basic lined furnace.

Acid lining is preferred with good shell scrap law so that removal of these two element is not require, the heat are produce much faster.

A basic lined furnace is advantageous because inferior scrap may be used to make good steel the basic process removes should P from the melt.

The roof of the E.A.F. consists of steel roofing in which silica bricks are fixed in position.

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The direct are furnace may be charged either from the charging door which also serves from removing slag from the molten metal or from the furnace roof which is made to lift off and swing clear of the F.C.

A few roofs can be made available at all times at the roof does not have a very long time.

Depending upon whether is it a two phase or three phase E.A.F., two or three graphite electrodes are inserted through the hole in the roof into the furnace.

Electrodes can be raised up or down for a 50 ton furnace each electrodes are inserted carries a current of the order of 25000 Amperes.

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Reactions :

2FeO + Si SiO2 + 2Fe

FeO + MnMnO.Fe

MnO + SiO2 MnO.SiO2

FeO + SiO2 FeO. SiO2

FeS + MnO + C MnS + Fe + CO

P2O5 + 3FeO (FeO)3.P2O5

(FeO)3.P2O5 + 3CaO (CaO)3.P2O5

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Process Flow Diagram

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Operation Steps : The interior of the furnace is preheated before charging the

metal charge in the furnace. The furnace is charged either by swinging over the roof or

through the charging door. Then the electric arc is flown between the electrodes and

surface of the metal charge, by lowering electrode down fill the current jump the gap between the electrode and the charge surface.

Three arcs burning simultaneously produce a temp of the order of 11000F and readily melt flux, sand etc. covers the molten pool of metal slag present on the top of the molten metal both reduce its oxidation.

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The molten pool increases in the size with the passage of time fill the whole of the scrap is melted.

Before the pouring the liquid metal into the ladle the furnace is tilted backward and the slag is poured off from the charging door.

The furnace is then tilted forward and the molten metal is emptied into ladles.

Hearth side walls and roof the furnace are repaired with the help of suitable refractory material after each heat.

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Advantages of EAF Process

Unlike crucible furnace direct arc furnace undertake a definite metal refining sequence.

Electric furnace lead themselves to close temp. and heat control.

Analysis of metal can be kept accurate limit.

A direct arc furnace has a thermal efficiency as high as about 70%.

Arc furnace is preferred for its :

Quicker readiness for use.

Longer hearth life.

Ease of repair.

Great independence of the quality of charge.

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Steel Production Capacity (in past years):

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