Cryogenic Treatment is a heat treatment method that involves cooling metal materials to extremely low temperatures. Typically, materials undergo normal heat treatment before being subjected to cryogenic treatment. The principle of cryogenic treatment is to utilize the changes that occur in the material at these low temperatures to improve its properties.
The main principles of cryogenic treatment include the following points:

1. Reduction of Residual Austenite: Austenite is a high-hardness and brittle phase that often forms on the surface or within materials. Cryogenic treatment can transform the residual austenite inside the material into a more stable structure, thereby reducing its negative impact on the material’s performance.
2. Promotion of Grain Refinement: Cryogenic treatment can promote the refinement of the material’s grain structure, which in turn enhances its hardness and strength.
3. Reduction of Stress: Cryogenic treatment can reduce the internal stresses within the material, thus minimizing deformation and fracture.

The process of cryogenic treatment involves placing the material in liquid nitrogen for cooling, with typical cooling rates of about 1°C to 10°C per second, maintained for a specific duration. Cryogenic treatment is commonly applied to high-strength and high-hardness metal materials such as high-speed steel, tool steel, stainless steel, and titanium alloys.

Furthermore, cryogenic treatment is not an independent heat treatment method; it serves as an auxiliary process to other heat treatment methods, and its effectiveness is influenced by those methods.