“Cryogenic temperature” is defined by the Cryogenic Society of America as temperatures below -140 ° C. For this reason, it is separated from the so-called sub-zero process or cold process by thermal processors. The temperatures used in the mentioned processes are at most -100°C.
The cryogenic process is a continuation of the heat treatment process which ends at room temperature. The aim is to maintain the martensitic transformation by decreasing to low temperatures and to reduce the residual austenitic amount as much as possible. Cryogenic treatment is performed in specially designed processor controlled chambers.