Cold & Cryogenic Treating
Quenching steel results in transformation of austenite into martensite, it is not completely transformed. There are some of the crystals of austenite that remain unchanged and are not affected by quenching below martensite-finish temperature. This can further be transformed into martensite, through slow cooling of the metal at extremely lower temperatures. Normally, cold treating includes steel`s cooling to -115F/-81C. this temperature doesn`t eliminate the austentite completely. In cryogenic treating, it is cooled-down to even lower temperatures, which normally fall within -316/-192C for transforming majority of respective austensite in to the martensite. Cryogenic and cold treatments are normally done techniques after quenching, but before tempering and increase wear resistance and hardness & reduce internal stresses within the metal. Due to the fact that it is a quenching process`s extension it increases cracking chances during the ongoing process. this process is used for bearings, tools and other items requiring good wear-resistance. This process is effective mostly in case of high carbon or high alloy steels within which there are over 10 percent maintenance of austenite after quenching.