The shot peening process involves using high - hardness and high - velocity moving shot to violently impact the surface of parts. During this process, intense plastic deformation occurs on the surface of the parts, resulting in the formation of a dense strengthening layer and a residual compressive stress layer on the surface layer. This can significantly improve the fatigue resistance and stress - corrosion resistance of the parts. It can also effectively delay the initiation and propagation of cracks, and even enhance the wear resistance of the parts, leading to a qualitative leap in the service life of the product.