The chemistry of steel determines why and how it should be tempered.
The potential hardness of a steel is determined by its carbon content. Adding small amounts of other elements to the mix can produce enormous improvements in strength, toughness, and
resistance to rust and the response of the steel to heat treatment.
Steels referred to as alloy steels have additional elements such as chromium, nickel, vanadium,
cobalt, manganese, molybdenum, silicon, and tungsten included.