Heat treating is a group of
industrial and
metalworking processes used to alter the
physical, and sometimes
chemical, properties of a material. The most common application is
metallurgical. Heat treatments are also used in the manufacture of many other materials, such as
glass. Heat treatment involves the use of heating or chilling, normally to extreme temperatures, to achieve a desired result such as hardening or softening of a material. Heat treatment techniques include
annealing,
case hardening,
precipitation strengthening,
tempering, normalizing and
quenching. It is noteworthy that while the term
heat treatment applies only to processes where the heating and cooling are done for the specific purpose of altering properties intentionally, heating and cooling often occur incidentally during other manufacturing processes such as hot forming or welding.