2022

How to prolong the service life of spring?

Author

2022-03-31 10:04

1. The isothermal quenching of precision springs can be used for springs with small diameter or sufficient hardenability, which can not only reduce the eccentricity, but also improve the strength and toughness. Conduct another tempering after isothermal quenching to increase the elastic limit. Tempering temperature is the same as isothermal quenching temperature. 2. Deformation heat treatment, which combines the deformation strengthening and heat treatment strengthening of steel to further improve the strength and toughness of steel. The deformation heat treatment is divided into high temperature, medium temperature and low temperature. High-temperature deformation heat treatment refers to quenching immediately after deformation in a stable austenitic state, or it can be used in combination with forging or hot rolling, that is, quenching immediately after hot forming. The automobile leaf spring made of 60Si2Mn steel is subject to high temperature deformation heat treatment (930 ° C, thermal variable 18%, oil quenching) and × Conduct rapid tempering at 3.25min. Its strength and fatigue life have been greatly improved. 3. Shot peening, shot peening is one of the methods to improve the surface quality of spring. Springs need high surface quality, and surface defects (such as scratches, wrinkles and oxidation decarburization) often become places where stress concentration and fatigue fracture occur during spring operation. If the surface of the spring is shot peened and shot peened with small steel shot at high speed, not only the surface quality of the spring can be improved, but also the surface strength can be improved, and the surface will be in the state of compressive stress, so that the spring surface will be in the state of compressive stress. Improve the fatigue strength and service life of the spring. 4. The release spring has worked for a long time under the action of external force. Due to stress relaxation, a small amount of long-term (plastic) deformation will occur. Especially for the spring working at high temperature, the stress relaxation phenomenon is more serious at high temperature, thus reducing the accuracy of the spring. Springs are not allowed. Therefore, this type of spring should be relaxed after quenching and tempering. Heat treatment process: preload the spring to make its deformation exceed the deformation that may occur when the spring works. Then heat it to a temperature 20 ℃ higher than the working temperature and keep it for 24h. 5. Low temperature carbonitriding For coil springs, tempering combined with low temperature carbonitriding (soft nitriding) can significantly improve the fatigue life and corrosion resistance of springs.