Spring material: high-quality chromium alloy spring steel is used, which has the characteristics of high temperature resistance, high rigidity and long life. Material modeling: It has a rectangular cross-section and rounded edge shape, which is different from the general rectangular right-angled edge. The spring can reduce stress concentration when running at high speed. Strong pressure treatment: The spring is subjected to more than three times of strong pressure treatment, which eliminates the internal stress before use, and will not deform and shorten the spring.