In modern industrial manufacturing, fatigue failure of metal components is one of the key factors affecting equipment life and safety. To improve the fatigue strength of metal materials, the engineering community widely adopts an efficient and economical surface hardening process called shot peening. Shot peening effectively delays the initiation and propagation of cracks by introducing compressive residual stress layers on the surface of the metal, thus significantly improving the fatigue life of components.



The basic principle of shot peening is to use high-speed pellets to impact the metal surface, causing plastic deformation on the material surface. Since the material inside is still in an elastic state, this deformation will cause compressive stress on the surface while tensile stress is formed inside to maintain mechanical balance. This surface compressive stress can offset the tensile stress generated by the external load, especially in areas of component stress concentration, such as notches, holes, or welding joints, which can significantly inhibit the initiation and propagation of fatigue cracks.

　　From the perspective of materials science, fatigue failure usually originates from micro defects or stress concentration areas on the material surface. Shot peening, by improving surface integrity, not only introduces beneficial compressive stress layers but also seals surface microcracks, improves surface hardness, and improves the microstructure. These factors work together to make the material more fatigue-resistant under repeated loading.kkkkkkk



Shot peening is widely used in fields that have extremely high requirements for fatigue performance, such as aviation, automotive, rail, and shipping. For example, critical components such as landing gears, turbine blades, gears, springs, and welded structural components usually undergo shot peening to enhance their service life. Studies have shown that through reasonable parameter control, shot peening can increase the fatigue limit of components by 20% to 100%, greatly enhancing the safety and reliability of the structure.

　　However, the effect of shot peening is influenced by many factors, such as the material of the pellets, size, jet speed, coverage, and jet angle. Therefore, in practical applications, it is necessary to optimize the shot peening process parameters according to the type of material and the component structure to ensure the best hardening effect. At the same time, with the development of science and technology, new surface hardening technologies such as laser shot peening (LSP) and ultrasonic shot peening (USP) are also emerging, providing more choices for further improving fatigue strength.



In summary, shot peening, as a mature surface hardening technology, has a significant advantage in enhancing the fatigue strength of metal materials. It can not only effectively extend the service life of components but also improve the safety and reliability of equipment operation, and has important engineering application value. In the future, with the continuous increase in the demand for high-performance materials in the manufacturing industry, the technology of shot peening will also continue to develop in process optimization and technological innovation.