弹簧在使用期间主要承受弯曲或扭转应力,并且在弹簧表面的应力达到最大值,因此其主要破坏方式是疲劳。这就要求弹簧材料必须具有高疲劳强度,尤其是扭转疲劳强度。螺旋弹簧的常规制作方法,不能使弹簧的强度分布对应地工作条件下的应力分布,也沒有考虑使晶粒细化。“循环加热淬火工艺”是 The spring is mainly subjected to bending or torsional stress during use and the stress on the spring surface reaches its maximum, so the main failure mode is fatigue. This requires that the spring material must have high fatigue strength, especially torsional fatigue strength. The conventional method of making a helical spring does not allow the distribution of the spring’s stress distribution to correspond to the working conditions nor to refine the grain. “Circulation heating quenching process” is