39939186 Basics of Steel Making

8/2/2019 39939186 Basics of Steel Making

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Customer Technical SymposiumSteelmaking 101


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Todays Topics

Steelmaking Flowline

Blast Furnace

Basic Oxygen Furnace: BOF

Vacuum Degasser

Continuous Casting

Hot Strip Mill

Pickler

Cold Strip Mill

Box Annealing

Temper Mill

Hot Dip Coating Line

Electrogalvanizing Line


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Iron Ore

Limestone

Coal

Pellets

Sinter

Crushed

Coke Ovens

Blast Furnace

Slag Molten Iron

Scrap

Lime & Flux

Oxygen

Electric

Furnace

Basic Oxygen

Furnace


Artwork: American Iron and Steel Institute


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Continuous Casting

Ladle

Metallurgy

Temper Rolling

Slab Hot Strip Pickling

Annealing

Cold Strip

Coating

Artwork: American Iron and Steel Institute


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Basic Steelmaking Flow

COKE OVENS

BLAST FURNACE

BASIC OXYGEN

FURNACECONTINUOUS CASTER

HOT STRIP MILLCOLD STRIP MILL PICKLING

TEMPER MILL COATING LINE

SHIPPING

SHIPPING

ANNEALING

SHIPPING SHIPPING


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Recipe

Blast Furnace

IRON ORE +

LIMESTONE +

COKE +

HOT AIR


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Blast Furnace Raw Materials

COKE

CRUSHED

SINTER

PELLETS


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Blast Furnace

Input Iron ore, coke, limestone and heatedair

Output

Molten Iron (Pig Iron) is cast intoTorpedo Cars

Transferred to Basic Oxygen

Furnace (BOF)

Metallurgy

Chemical reactions cause heating,reduction and melting

Impurities separate and float on top ofthe molten iron as slag


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Blast Furnace


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COKE (carbon) + OXYGEN CARBON MONOXIDE + HEAT

C+O2 CO + HEAT

IRON ORE + CARBON MONOXIDE IRON + CARBON DIOXIDE

FeO + CO Fe + CO2

LIMESTONE SLAG - LIQUID BLANKET - FLOATS ON IRON BATH

Blast Furnace


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Input Molten iron, scrap, and high purityoxygen

Output

Molten steel is tapped into a ladle Transferred to the ContinuousCaster after chemistryadjustments or vacuum degassing

Metallurgy

Impurities are oxidized and someseparate / float on top of the moltensteel as slag


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OXYGEN + CARBON CO + HEAT

OXYGEN + MANGANESE MnO (SLAG)

OXYGEN + PHOSPHORUS P2O5 (SLAG)

OXYGEN + SILICON SiO2 (SLAG)



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Vacuum Degasser

Input Molten steel from basic oxygenfurnace (BOF)

Metallurgy

Vacuum degasser snorkels insertedinto ladle of molten steel

Argon gas siphons molten steelthrough a vacuum chamber

Dissolved gases and carbon are

removed

Output Ultra-low carbon steel

Transferred to the ContinuousCaster

To Vacuum

Pump

Ladle

Inert Gas Inlet


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Continuous Caster

Input

Molten steel from ladle is transferred

into a holding vessel (tundish) on top

of the Continuous Caster

The tundish continuously meters

molten steel into a water-cooled,oscillating mold via a Submerged

Entry Nozzle (SEN)

Output

Solid slabs are torch-cut

Slabs transferred to Hot Strip

Mill for Rolling


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Continuous Caster


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HotStrip Mill

Input

Slabs from the Continuous Casterare reheated and placed on a rollingtable

Six roughing mill stands reduceslabs thickness to 1.25 -

producing a bar The bar is sent through sevenadditional 4-high finishing millstands to further reduce thickness

Output

Hot bands from


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HotStrip Mill


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Pickler

Input

Hot bands of steel are processed

through a chemical bath to remove

surface oxides

Output

Pickled (Oiled) Band - free of

surface rust and scale

Transferred to Cold

Mill orShipped to Customer.


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Cold Strip Mill

Input

Pickled Bands are rolled through fivemill stands (4 or 6-High)

Output

Cold Roll Full Hard coils with proper

thickness and surface finish Transferred to Box Annealing, HotDip Coating Line or shipped toCustomer


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Box Annealing

Input

Cold rolled Full Hard coils are

stacked, covered and a non-oxidizing

atmosphere is introduced

A furnace is lowered over the coverand fired to a prescribed cycle of time

and temperature

Output

Annealed steel with improved

mechanical properties

Transferred to TemperMill


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Temper Mill

Input

Annealed coils

Output

Cold Roll steel with continuous yielding,improved flatness and a uniform surfacetexture

Thickness typically reduced


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Hot Dip Coating Line

Input Coils are welded together forcontinuous processing

Continuous annealing in-line

Continuous coating on both sides

Zinc or Aluminum

Output

Hot Dip Galvanized, Galvannealed orAluminized steel

Shipped to Customer


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Electrogalvanized Line

Input Cold Roll (Box Annealed &Tempered) coils are welded togetherand continuously processed throughthe line

Plating cells use electric current toapply zinc to the steel

Output

Electrogalvanized

steel Shipped to

Customer


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Electrogalvanized Line


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39939186 Basics of Steel Making

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