​Special-shaped springs include circlips, extension springs, and torsion springs. Generalized special-shaped springs also include serpentine springs, wave springs, rod springs and other springs with complex shapes. Special-shaped springs are basic parts with a wide range of applications and various varieties in automobiles, motorcycles, electrical appliances, and instrument products. Their quality and life span directly affect the performance of the host product. Modern automobile manufacturing has listed it as one of the key parts.

More than 90% of special-shaped springs at home and abroad are made of lead-quenched cold-drawn carbon steel or cold-work-hardened austenitic stainless steel. Its characteristics do not need to be quenched, and only need low-temperature tempering after winding, which eliminates cold drawing The residual stress in the process of, hardening and coiling of the spring simplifies the process and is widely used. Carbon steel wire and stainless steel wire are mainly graded according to their tensile strength. Commonly used domestic carbon steel wires are grade D and C, Japanese and Korean grades are SWP-B, SWP-A; domestic stainless steel grades are 1Cr18Ni9, Japan and Commonly used grades in Korea are SUS302 and SUS304.

Development and material requirements of special-shaped springs
With the rapid development of the automobile industry, the technical content of special-shaped springs is constantly improving. The entry of WTO has made the competition between the foreign automobile industry and the domestic industry more fierce. Technical barriers are currently facing problems, and independent product development is the development trend. The technical focus of special-shaped springs is different from that of valve springs and precision springs. They are not under long-term dynamic load conditions of reciprocating work. They mainly bear the static load during assembly. Size and deformation are the key indicators of special-shaped springs. Product design One unit always gives priority to size fit. Therefore, the current special-shaped springs are basically manufactured according to the patterns designed by the customers, but the joint design and development of products with the OEM tends to increase.

The quality of raw materials is the key to forming special-shaped springs. The quality of raw materials affects the supply of springs. Compared with foreign materials, domestic raw materials have the following gaps, such as: large dispersion of strength, obvious bamboo joints, surface folding, etc., which make it difficult to control the size during the manufacturing process, and cracks or breaks are prone to bends. Stainless steel materials are especially obvious. All are processed with imported materials.