Editing Heat treating (section)

===Cold and cryogenic treating===
{{Main|Cryogenic treatment}}
Although quenching steel causes the austenite to transform into martensite, all of the austenite usually does not transform. Some austenite crystals will remain unchanged even after quenching below the martensite finish (M<sub>f</sub>) temperature. Further transformation of the austenite into martensite can be induced by slowly cooling the metal to extremely low temperatures. Cold treating generally consists of cooling the steel to around -115˚F (-81˚C), but does not eliminate all of the austenite. Cryogenic treating usually consists of cooling to much lower temperatures, often in the range of -315˚F (-192˚C), to transform most of the austenite into martensite.

Cold and cryogenic treatments are typically done immediately after quenching, before any tempering, and will increase the hardness, wear resistance, and reduce the internal stresses in the metal but, because it is really an extension of the quenching process, it may increase the chances of cracking during the procedure. The process is often used for tools, bearings, or other items that require good wear resistance. However, it is usually only effective in high-carbon or high-alloy steels in which more than 10% austenite is retained after quenching.<ref>''Heat treater's guide: practices and procedures for irons and steels'' By ASM International - ASM International 2007 Page 12-13</ref><ref>''Handbook of residual stress and deformation of steel'' by George E. Totten, Maurice A. H. Howes, Tatsuo Inoue - ASM International 2002 Page 331-337</ref>