Chemical composition is the most widely used basis for classification.
Alloy Steel is steel containing substantial quantities of nickel, chromium, silicon, manganese, tungsten, molybdenum and vanadium to increase hardness, strength or chemical resistance. The more carbon that is dissolved in the iron, the less formable and the tougher the steel becomes. Typically used in automotive body applications. Tool Steel is any high carbon or alloy steel that can be used for cutting, shaping, forming and blanking steels and other materials. They have additional applications in which strength, toughness, and resistance to wear are required.