The manufacturing process of coil spring includes: rolling, processing of both ends (referring to compression springs) or the production of hooks (referring to tension springs or torsion springs), heat treatment and workmanship inspection, and important springs are also subjected to strong pressure treatment.
There are two types of spring forming processes, cold rolling and hot rolling. When the diameter of the spring wire is less than or equal to 8mm, the cold rolling method is usually used. No matter the low cold coil or the hot coil spring, different heat treatments are required. After the spring is rolled and heat treated, surface inspection and process tests are required to identify the quality of the spring. After the spring is made, special treatment (such as strong pressure treatment or shot peening treatment) can be carried out to improve the bearing capacity and fatigue life of the coil spring.