The principle of nitriding barrel mainly involves nitriding treatment, this is a chemical heat treatment process that penetrates nitrogen into the surface of steel parts, is aimed at forming a nitrogen-rich hardening layer. nitride treatment is usually carried out at the temperature of 500~600℃. the active nitrogen atoms generated by the decomposition of ammonia permeate and diffuse to the surface layer of steel, forms an iron-nitrogen alloy, which changes the mechanical properties.