With the increase of industrial products, spring products have become more enriched, the amount of spring has been gradually increased, and spring-related technologies have gradually matured. How to increase the spring life is the spring production enterprises need to face the following to share with you some of the commonly used spring mattress wire method.
(1) deformation heat treatment
Deformation heat treatment is the combination of steel deformation strengthening and heat treatment to strengthen and further improve the strength and toughness of steel. Deformation heat treatment has high temperature, moderate temperature and low temperature. High-temperature heat treatment is a deformation in the steady state of austenitic deformation immediately after quenching can also be combined with forging or hot rolling, that is, quenching immediately after thermoforming. 60Si2Mn steel automotive leaf springs, high temperature deformation heat treatment (930 ℃ + 18% of thermal variables, oil quenching), the use of high temperature 650 ℃ × 3.25min rapid tempering, the strength and fatigue life have been greatly improved.
(2) isothermal quenching of the spring
For smaller diameter or hardenability adequate spring isothermal quenching, it can not only reduce the change of heart, but also improve the toughness. After isothermal quenching is best to conduct a further tempering, can increase the elastic limit, tempering temperature and isothermal quenching temperature the same.
(3) Shot peening
Shot peening is one of the most widely used methods for improving the surface quality of springs. Spring requires a higher surface quality, scratches, folds, oxidation and decarburization and other surface defects tend to be the spring work stress concentration and fatigue fracture source. If a small steel shot blasting the spring surface at high speed, shot peening, not only improve the spring surface quality, improve the surface strength, the surface is in a state of compressive stress, thereby increasing the spring fatigue strength and service life.
(4) spring relaxation treatment
Spring for a long time under the action of external force, due to stress relaxation, will produce a small amount of permanent (plastic) deformation, especially the high temperature work of the spring, stress relaxation phenomenon is more serious at high temperatures, the spring accuracy, which is generally sophisticated Spring is not allowed. Therefore, this type of spring after quenching, tempering should be relaxed. Heat treatment process: the pre-load on the spring, making it more than the amount of deformation of the spring may produce deformation. Then heated above the working temperature of 20 ℃, incubated for 8 ~ 24h.
(5) low-temperature carbonitriding
For the spring coil with tempering and low temperature carbonitriding (nitrocarburizing) combination of technology, can significantly improve the spring fatigue life and corrosion resistance.