According to modern metal strength theory, increasing the dislocation density inside the metal is the main direction to improve the strength of the metal. Practice has proved that shot blasting is an effective process to increase the metal dislocation structure. This is of great significance for some metals that cannot be hardened by phase transformation (such as martensitic quenching) or require further strengthening on the basis of transformation hardening. Aviation, aerospace industry, automobiles, tractors and other parts require lighter weight, but the reliability requirements are getting higher and higher. An important process measure is to use shot blasting to improve the strength and fatigue strength of components.