The cryogenic process is a continuation of the heat treatment process that ends at room temperature. The aim is to keep the martensitic transformation at low temperatures and to reduce the residual austenite amount as much as possible. Cryogenic process is carried out in specially designed processor controlled chambers.
Effects of the cryogenic process:
Removal of residual austenite and transformation of the structure into martensite
Homogeneous precipitation of very fine η-carbide (etacarbide) particles in martensite matrix
Regulation of the hardness distribution
Elimination of internal stresses / residual stresses (affects many mechanical properties)
Increases toughness, increases wear resistance, increases fatigue strength