Ways to improve spring quality

There are several ways to improve spring quality:
(1) Austempering of springs For springs with small diameters or sufficient hardenability, austempering can be used. It can not only reduce the centering, but also improve the strength and toughness. It is best to perform tempering again after austempering, which can improve The elastic limit, the tempering temperature is the same as the austempering temperature.
(2) Thermomechanical heat treatment is a combination of deformation strengthening and heat treatment strengthening of steel to further improve the strength and toughness of steel. Thermomechanical heat treatment is divided into high temperature, medium temperature and low temperature. High temperature deformation heat treatment is a stable austenite It can be quenched immediately after deformation occurs in the state, or can be combined with forging or hot rolling, that is, quenched immediately after hot forming. Automobile leaf springs made of 60Si2Mn steel are subjected to high temperature deformation heat treatment (930℃+thermal variable 18%, oil quenching) After that, using 650℃×3.25min high temperature rapid tempering, its strength and fatigue life have been greatly improved.
(3) Spring relaxation treatment. Springs work under external force for a long time. Due to stress relaxation, a small amount of permanent (plastic) deformation will occur. Especially for springs that work at high temperatures, the stress relaxation phenomenon is more serious at high temperatures, making the spring The accuracy is reduced, which is not allowed for general precision springs. Therefore, this type of spring should be relaxed after quenching and tempering. Heat treatment process: pre-load the spring to make its deformation exceed the deformation that may occur when the spring is working Quantity. Then heat it under the condition of 20℃ higher than the working temperature and keep it for 8~24h.
(4) Shot peening Shot peening is currently one of the most widely used methods to improve the surface quality of springs. Springs require high surface quality, and surface defects such as scratches, folds, and oxidative decarburization often become springs when they work. The place where the stress is concentrated and the source of fatigue fracture. If small steel shots are used to spray the surface of the spring at high speed and perform shot peening, it will not only improve the surface quality of the spring, increase the surface strength, and put the surface in a state of compressive stress, thereby improving the fatigue strength and use of the spring life.
  (5) Low-temperature carbonitriding is a combination of tempering and low-temperature carbonitriding (soft nitriding) for coil springs, which can significantly improve the fatigue life and corrosion resistance of the spring.