Shot blasting is also the name of a mechanical surface treatment process. Similar processes include sand blasting and shot blasting. Shot blasting is a cold treatment process, which is divided into shot blasting cleaning and shot blasting strengthening. As the name suggests, shot blasting cleaning is to remove impurities such as surface oxide skin and improve the appearance quality. Shot blasting strengthening is to continuously impact the strengthened workpiece surface by using the high-speed projectile flow (60-110m / S). Continuous sand blasting and shot blasting forces the following changes to the target surface and surface layer (0.10-0.85mm) in the process of cyclic deformation: 1 The microstructure was modified; 2. Residual compressive stress is introduced into the non-uniform plastic deformation outer layer, and residual tensile stress is generated in the inner surface layer; 3. The outer surface roughness changes (RA RZ). Effect: it can improve the fatigue fracture resistance of materials / parts, prevent fatigue failure, plastic deformation and brittle fracture, and improve fatigue life.