IRON & STEEL
Alloy steel is steel alloyed with a variety of elements in amounts of between 1 and 50% by weight to improve its mechanical properties. Alloy steels are broken down into two groups: low alloy steels and high alloy steels. The differentiation between the two is somewhat arbitrary; Smith and Hashemi define the difference at 4%, while Degarmo, et al., define it at 8%. However, most commonly alloy steel refers to low alloy steel.
These steels have greater strength, hardness, hot hardness, wear resistance, hardenability, or toughness compared to carbon steel. However, they may require heat treatment to achieve such properties. Common alloying elements are molybdenum, manganese, nickel, chromium, vanadium, silicon and boron.