How to improve the service life of profiled springs?
1. Deformation Heat Treatment
Deformation heat treatment is a combination of deformation strengthening and heat treatment strengthening of steel to further improve the strength and toughness of steel. Deformation heat treatment has high temperature, medium temperature and low temperature.
High-temperature deformation heat treatment is in a stable austenite state immediately after quenching after deformation, can also be combined with forging or hot rolling, that is, hot forming immediately after quenching.
2. isothermal quenching of springs
For a small diameter or hardenability enough spring can be used isothermal quenching, which not only reduces deformation, but also improves toughness. After isothermal quenching, it is best to perform a tempering.
can improve the elastic limit, tempering temperature and isothermal quenching temperature is the same.
3. Shot Peening
Shot peening is currently one of the most widely used methods to improve the surface quality of the spring. Spring requires a high surface quality, scratches, folding, oxidation decarburization and other surface defects often
Will become the spring work where the stress concentration and fatigue fracture source. If the spring surface with fine steel shot at high speed, shot peening, not only to improve the surface quality of the spring, but also to improve the surface strength, so that the surface of the
Can also improve the surface strength, so that the surface is in a state of compressive stress, thereby improving the spring fatigue strength and service life.
4. Spring relaxation treatment
Spring work for a long time under the action of external forces, due to stress relaxation, will produce a small amount of permanent (plastic) deformation, especially the high temperature work of the spring, the stress relaxation phenomenon in high temperature
More serious, so that the accuracy of the spring is reduced, which is not allowed for general precision springs. Therefore, this type of spring should be quenched and tempered after relaxation treatment.
5. Heat treatment process
The spring is preloaded so that the deformation exceeds the amount of deformation that can be produced when the spring is working. Then heated at a temperature higher than the working temperature of 20 ℃, holding 8-24h.
6. Low-temperature carbonitriding
For coil springs using a combination of tempering and low-temperature carbonitriding (nitrocarburizing) process, can significantly improve the fatigue life of the spring and corrosion resistance.