Alloy Steel

Alloy Steel
Alloy Steel
• Other elements (besides carbon) can be
added to iron to improve mechanical
property, manufacturing, or environmental
property.
• Example: sulfur, phosphorous, or lead can
be added to improve machine ability.
– Generally want to use for screw machine
parts or parts with high production rates!
– Examples: 11xx, 12xx and 12Lxx
• Again, elements added to steel can dissolve in
iron (solid solution strengthening):
– Increase strength, hardenability, toughness, creep,
high temp resistance.
• Alloy steels grouped into low, med and highalloy
steels.
– High-alloy steels would be the stainless steel groups.
– Most alloy steels you’ll use fall under the category of
low alloy.
Alloy Steel
• > 1.65%Mn, > 0.60% Si, or >0.60% Cu
• Most common alloy elements:
– Chromium, nickel, molybdenum, vanadium,
tungsten, cobalt, boron, and copper.
• Low alloy: Added in small percents (<5%)
– increase strength and hardenability
• High alloy: Added in large percents (>20%)
– i.e. > 10.5% Cr = stainless steel where Cr improves
corrosion resistance and stability at high or low
temps
Alloying Elements used in
Steel
Manganese (Mn)
• combines with sulfur to prevent brittleness
• >1%
– increases hardenability
• 11% to 14%
– increases hardness
– good ductility
– high strain hardening capacity
– excellent wear resistance
• Ideal for impact resisting tools