1, (Jiusheng Spring) heat treatment in protective atmosphere. In China, the heat treatment of springs, oil-quenched tempered steel wires and tempered steel with steel wires less than 15mm is carried out in a protective atmosphere. Heat treatment in protective atmosphere can eliminate decarburization and oxidation on the surface and improve the surface quality of materials.

2, induction heating or protective atmosphere induction heating heat treatment. This process is usually carried out on-line before the coil spring is formed. In order to reduce costs, some spring factories put wire heat treatment and spring production together. Induction heating treatment has good strengthening effect and fast induction heating speed, which is helpful to refine grains, reduce surface decarburization, and give full play to and improve the strength and toughness of materials.

With the more and more extensive application of springs, the requirements for the technicality of spring fittings and the diversity of products are getting higher and higher.