5

Iron Ore and Steel

A.) Mining Iron Ore

1.) Drill and blast

Hematite (Fe203)

Magnetite (Fe304)

2.) Shovel into a truck and bring to mill

3.) Crush into a powder

4.) Add clay and roll into balls, harden in kiln

5.) Ship to steel mill

http://www.cleveland-cliffs.com/MiningOperations&Technology/

Open Pit Mining

Blasting Hauling

Crushing

Secondary MillPrimary Mill

Separating Iron Concentrate from Impurities

Settling Tank Magnetic Separation

Removing Water Rolling into Pellets

Hardening in Kiln Pellet Stockpile

B.) Making Pig Iron from Iron Ore

1.) Melt Iron Ore in a Blast Furnace with Limestone and coke.

2.) Coke is almost pure carbon made from coal.

3.) Limestone is a flux, it helps remove impurities such as sand from the iron.

4.) Blowing hot air (11000F) past the coke causes a reaction that creates high enough temperatures (30000F) to melt the iron.

B.) Making Pig Iron from Iron Ore

Figure prepared by John A. Ricketts, Ispat Inland, Inc.

B.) Making Pig Iron from Iron Ore

Figure prepared by John A. Ricketts, Ispat Inland, Inc.

C.) Making Steel from Pig Iron

1.) heating pig iron (4%C) in a Converter burns off Carbon to 2% or less.

a.) Electric Arc Furnace

b.) Oxygen Lance Furnace

2.) scrap steel and alloying elements are added to the pot .

3.) test steel composition.

4.) steel is cast into ingots or or continuous pours.

Iron Ore and Steel

Figure from AISI website: http://www.steel.org/learning/flowline/index.htm

Basic Oxygen Steelmaking Plant showing scrap being charged into the BOF vessel. A ladle full of hot metal is seen to the right. John Stubbles photo

C.) Making Steel from Pig Iron

A ladle of molten steel leaving for the ladle metallurgical facility or the caster. John Stubbles photo

BOF Vessel in Its Operating Positions

BOF Vessel in Its Operating Positions. (Ref: Making, Shaping, and Treating of Steel, 11th Edition, Steelmaking And Refining Volume. AISE Steel Foundation, 1998, Pittsburgh PA)

1.1. 2.

3. 4.

5. 6.

C.) Making Steel from Pig Iron

Section through the BOF vessel during oxygen blowing. (Ref: Making, Shaping, and Treating of Steel, 11th Edition, Steelmaking And Refining Volume. AISE Steel Foundation, 1998, Pittsburgh PA)

C.) Making Steel from Pig Iron

Figure from AISI website: http://www.steel.org/learning/flowline/index.htm

C.) Making Steel from Pig Iron - Electric Arc Furnace

Figure by Jeremy A. T. Jones, Nupro Corporation

D.) Rolling Mill

Figure from AISI website: http://www.steel.org/learning/flowline/index.htm

D.) Rolling Mill1.) Slabs are rolled into sheets (<1/4”)or plates (>1/4”).2.) Blooms are made into Billets.3.) Billets are rolled into bars and

shapes.4.) Bars can be drawn into wire.5.) Effects of rolling.

a.) Anisotropic properties.b.) Cold rolling hardens steel more than hot rolling.

E.) Nomenclature

10--Plain Carbon

11-- Free Machining

13--High Manganese

2---Nickel Steels

Etc.

http://www.geneva.com/tour.html

http://www.geneva.com/tour.html

G.) References1.) AISI Website http://www.steel.org/learning

2.) John A. Ricketts, Ispat Inland, Inc.

3.) John Stubbles, Steel Industry Consultant

4.) By Jeremy A. T. Jones, Nupro Corporation

F.) Forging

1.) Open-Die Drop-Forging

CAST IRON

A.) Gray Cast Iron

1.) Composition (in addition to Fe):4% Carbon (+) in the form of graphite

flakes that form tiny cracks. 1-3% Silicon (Si) Trace amounts of Mn and P

2.)Classified by Tensile Strength

ASTM 20 means u = 20 ksi

A.) Gray Cast Iron

3.) Advantages

soft, easy to machinegood damping inexpensive

A.) Gray Cast Iron

B.) White Cast Iron

1.) Composition (in addition to Fe):2.5-3.5% Carbon (+) C in combined form

(iron carbide) 1-3% Silicon (Si)

2.)Classified byu, y, and %LExample/ 60:40:18

3.) Advantageshard (BHN > 400) - good wear resistance

( grinding mills etc.) good dampinghigh compressive strength ( 200,000 psi)

B.) White Cast Iron

4.) DisadvantagesBrittleDifficult to machine

B.) White Cast Iron

C.) Ductile Iron

1.) Composition: Carbon is in nodular (round) form instead of free flakes or iron carbide):

2.5-3.5% Carbon (+) 0.80% Mn 1.8-2.8% Si

2.)Classified byu, y, and %L Example/ 60:40:18

C.) Ductile Iron

1.) Nodule Photo

3.) AdvantagesHigh Tensile Strength (50-100ksi)

(40-150 ksi Compressive Strength)High Ductility (2-15%)

3.) DisadvantagesHigher Cost than Gray Cast Iron

C.) Ductile Iron