IT 111 Iron and Steel

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IT 111 Iron and Steel

• Lecture 4
• Thomas E. Scott

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Definitions

• Pig Iron product of blast furnace
• Cast Iron - gt 4 carbon, malleable at all temps
• Nodular Cast Iron adding magnesium or cerium
  higher strength ductile iron
• Steel malleable alloy of iron and carbon,
  usually significant quantities of manganese
• Carbon steel properties related to carbon
• Alloy steelproperties to element besides carbon
• Hardenabilitydepth and distribution of hardness

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Examples

• See Table 6 of Machinery Handbook 24
• HANDOUTS FOR LECTURE 4
• Laboratory 3

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Tool Steels

• Examples
• W-1 Water hardening 1 carbon used for cold
  working of metals
• D3 High chromium with 2.25 carbon for cold
  working applications
• S2 Shock resistant hammer or chisel steel
• SEE TABLE 3 of Machinerys Handbook 24

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Heat TreatmentDefinitions

• Annealing heating to a temperature, holding,
  and cooling at a suitable rate
• Aging - Time and temperature change in properties
  of certain alloys
• Heat treating Combination of heating and
  cooling to attain desired properties
• Quenching Rapid cooling
• Stress Relieving process to reduce internal
  residual stress

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Heat TreatmentDefinitions

• Tempering reduction of brittleness
• Critical temperature Transformation at which a
  change in phase occurs

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Heat Treatment

• Phase Diagram page 457
• Machinerys Handbook 24
• Austenite normal solution at high temp
• Martensite solution formed when rapid cooling
  suppresses formation of pearlite (HIGH HARDNESS)
• (Ferrite or Cementite) and Pearlite normal
  solution at lower temperatures

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Surface Hardening

• Case Hardening
• Carburizing (carbon powder), nitriding (Nitrogen
  gas), cyaniding, carbon-nitriding
• Flame hardening
• Surface heating and then quenching
• Induction hardening
• Electrical heating (coil high frequency)