Cryogenic hardening

Cryogenic hardening is a cryogenic treatment process where the material is cooled to approximately , usually using liquid nitrogen. It can have a profound effect on the mechanical properties of certain steels, provided their composition and prior heat treatment are such that they retain some austenite at room temperature. It is designed to increase the amount of martensite in the steel's crystal structure, increasing its strength and hardness, sometimes at the cost of toughness. Presently this treatment is being practiced over tool steels, high-carbon, and high-chromium steels to obtain excellent wear resistance. Recent research shows that there is precipitation of fine carbides (eta carbides) in the matrix during this treatment which imparts very high wear resistance to the steels.