Puddling Furnace
Bessemer Process
u Sir
Henry Bessemer
t Inventions
Low Arched Roof With
Two Chambers
u Molten Iron &
Combustion Chamber
Are Separated
u
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t Bessemer Process (Beginning 1855)
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Bessemer Process (Continued)
u Very
Simple Idea
t Dismissed At First By All So-Called Experts
t Observation
Bessemer Process (Continued)
u Numerous
t 770 lb Iron (1/3 Ton) & Required 30 Minutes
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t Ordinary Air - 21% Oxygen
t Converter (Pear) Tilted For Charging & Pouring
u Process
t Recall, To Convert Molten “Cast” Iron To Wrought
Iron, The Carbon Must Be Removed
t Bessemer Blew Cold Air Through The Molten Iron
t Though He Produced Wrought Iron
t However, He Produced Malleable Iron “Steel”
u Produced
u Process
Bessemer Process (Continued)
u
t Experts Thought It
Would Cool Iron
Like A Volcano
u Most Spectacular
Sight In Iron & Steel
Industry
u Clear Flame Finally
From Converter
u Shown - 25 Ton
Difficulties
t Bessemer Licensed Process
t Licensees Could Reproduce Quality Of Steel
Bessemer Process (Continued)
Iron Gets Hotter As
Cold Air Passes
Through It
Mild Steel
t Could Be Bent & Formed Without Heat
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u
Patents (1855 To 1856)
Setup
u Experimental
Experimental Plant At
St. Pancras
t Ore Mined At Blaenavon
Blaenavon,,
Gwent (No Phosphorous)
u
u
Bessemer Plant At
Sheffield (1905)
t Made A Fortune
t Steam Boilers (1860)
t Railway Rails (1863)
1
Thomas Process
u P.G.
Thomas, Police-Court Clerk & Scientist
Phosphorous Problem
u Removed
t Lined Converter With Dolomite
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u Thomas
Process Spread Quickly To Regions
With Phosphorous Iron Ores (Most Abundant)
Siemens Process
u C.W.
Siemens,, Germany
Siemens
t Improving Furnaces For Glass Making
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t First Applied To Steel Making In France
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Basic Oxygen Process
u Advancement
Of Bessemer & Thomas
Process
u Air Is Replaced With High Pressure Stream
t Pure Oxygen
t Oxygen Lance (Water-Cooled Tip)
t Supersonic Speed
u 275
tons Per hour
Siemens Process (Continued)
u Phosphorous
& Non-Phosphorous Molten Iron
u Cost
t Bessemer Was Cheaper (No Fuel) But Required
Molten Iron
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t Siemens Required Fuel
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u Speed
t Siemens Process
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t Bessemer - 30 min
t Siemens - 10 hours
u Could
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Open-Hearth Process
u Derived
From Siemen’s Process
u Components
t Rectangular Brick Hearth (20’x30’x8’)
t Regenerative Preheating
u Operates
At 3000oF
t Steel Melts At 2500oF
u Produces
100 tons Per hour
Melt Scrap Iron
Open-Hearth Furnace
u Process
Of Producing Steel
t Furnace Can Be Charged With
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t Carbon Content Is Lowered By
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t Impurities Combine With Limestone As Slag
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Open-Hearth Furnace
Electric Furnaces
u Electric
Arc Or Electric Induction
u Primary Use Is Alloy & Specialty Steels
t Charge Is Usually Scrap
t Limestone & Iron Ore Are Added In Small Amounts
t No Contamination From Fuel
t Alloying Elements Are Added In Charge Or Later
u Electric
Arc
t Refractory Lined Vessel Of Drum Shape
t Heat Is Generated By Electric Arc
u Electric
Induction
t Electric Current Induces Secondary Current In Vessel
Electric-Arc Furnace
Classifications Of Steels
u Carbon
Steels
Steels
u High-Strength Low-Alloy Steels
u Stainless Steels
u Tool Steels
u Alloy
Carbon Steels
u 90%
Of All Steels
u Composition
t Varying Amounts Of Carbon
t Less Than 1.65% Maganese
t Less Than 0.60% Silicon
t Less Than 0.60% Copper
u Uses
t Auto Bodies, Machines, Structural Steel For
Buildings, Ship Hulls, Etc.
Alloy Steels
u Composition
t Certain Percentages Of
Vanadium, Molybdenum, Or
Other Elements
t Larger Amounts Of Maganese
Maganese,,
Silicon, & Copper Than Carbon
Steels
u Uses
t Auto Gears & Axles, Knives
3
High-Strength Low-Alloy Steels
u Called
HSLA
u Combination
Between Carbon Steels &
Alloy Steels
u Cost Less Than Alloy Steels
u Stronger Than Carbon Steels
Stainless Steels
u Composition
t Chromium
t Nickel
t Other Alloying Elements
u Properties
t Corrosion Resistance
t Hard & Strong
Tool Steels
u Composition
t Tungsten
t Molybdenum
t Cobalt
t Other Alloying Elements
u Properties
t Hardness
4