1. Process 1: The hot pressure process of the spring
In addition to improving the resistance to permanent deformation, the hot press process of spring can also increase the fatigue life. This process is mainly used in coil springs that require high resistance to permanent deformation.
2. Process 2: Shot peening process of spring
① Combination shot peening technology. Combination shot peening is generally called multiple shot peening. Most economical processes are mainly used for secondary shot peening, which is achieved by using different diameters of shot peening. Large pellets to obtain residual compressive stress and surface finish.
② Stress shot peening process. The stress shot peening process is also a relatively classic shot peening process, but it is difficult to apply to mass production. However, in recent years, due to the rapid development of stress shot peening equipment, high-stress automobile suspension springs have been mass-produced Production, especially the combined application of stress-strengthening shot peening and other shot peening processes, has realized a good strengthening effect. The fatigue strength is improved.
3. Process 3: Heat treatment strengthening process technology of spring
① Protective atmosphere heat treatment. That is, the protective atmosphere heat treatment can eliminate surface decarburization and oxidation, and improve the surface quality of the material. In China, the heat treatment of springs with wire less than 15mm, oil quenched and tempered steel wire and toughened steel are all used in this Kind of craft.
②Induction heating or protective atmosphere induction heating heat treatment. This process is generally carried out on the wire before the coil spring is formed, and has a good strengthening effect. The induction heating speed is fast, which helps to refine the crystal grains and reduce surface decarburization. It can give full play to and improve the strength and toughness of the material.
③Surface nitriding heat treatment technology. In recent years, in order to achieve reliable fatigue life for high-stress valve springs or other high-stress clutch springs, surface nitriding technology has also been adopted. Now the more advanced technology is low-temperature gas nitriding technology. The nitriding temperature is 450~470℃, and the gas nitriding time is 5~20h.