What is the effect of shot peening on the material surface?

 　Shot peening is a process that impinges on the workpiece surface by using sand and iron shot sprayed at high speed to improve the mechanical properties of parts and change the surface state. It can be used to improve the mechanical strength of parts, wear resistance, fatigue resistance and corrosion resistance, and can also be used for surface extinction, skin removal and optimization of casting, forging, welding residual stress.

　　Shot peening process is the process of spraying a large number of projectiles to the surface of the parts, like countless small hammer hammer on the surface, therefore, the surface of metal parts produce very strong plastic deformation, the surface of the parts produce a certain thickness of cold hardening layer, known as the surface strengthening layer, the strengthening layer will significantly improve the fatigue strength of parts.