Shot peening is also the name of a mechanical surface treatment process, and similar processes include sand blasting and shot peening. Shot blasting is a cold treatment process, which is divided into shot blasting cleaning and shot blasting strengthening. As the name implies, shot blasting cleaning is to remove impurities such as oxide scale on the surface and improve the appearance quality. Shot peening is to continuously impact the surface of the strengthened workpiece with high-speed projectiles (60- 1 100 m/s) and force the target surface and surface layer (0. 10-0.85 mm). 2. Uneven plastic deformation leads to residual compressive stress on the outer surface and residual tensile stress on the inner surface; 3. The roughness of the outer surface changes (larz). Influence: It can improve the fatigue fracture resistance of materials/parts, prevent fatigue failure, plastic deformation and brittle fracture, and improve fatigue life.