材料期刊网

随着对汽车轻量化和安全性要求的不断提高，改善疲劳性能成为弹簧钢研究与开发的一个重要主题。本文在Amsler HFP 5000高频疲劳试验机上研究了弹簧钢55SiCrA轴向拉-压加载的疲劳性能，测定了其条件疲劳极限及S-N曲线，利用扫描电镜(SEM)和E-DAX对疲劳断口及夹杂物进行观察，对断口进行了宏观和微观分析，研究了疲劳破坏的机理。试验结果表明：试验钢的条件疲劳极限为820MPa，σ-1p/σb=0.562（Nf=107）；疲劳裂纹源主要起源表面，较大的夹杂物（约20、30μm）也成为了疲劳裂纹源；疲劳裂纹稳定扩展区的疲劳条带宽度约为1.5~2.0μm。

Improving the fatigue properties of spring steel has became an important theme of R&D on spring steel with continuous improvement requirements of automotive lightweight and safety. In this paper, the axial tension and compression load fatigue behavior of spring steel 55SiCrA was studied by Amsler HFP 5000 high-frequency fatigue testing machine. Fatigue limit and S-N curve were measured. Fracture surfaces and non-metallic inclusions were observed by SEM and E-DAX, and mechanism of fatigue failure was analyzed. The results showed that the fatigue limit of 55SiCrA was 820MPa and σ-1p/σb was 0.562(Nf=107). Fatigue crack initiated mainly from surface and non-metallic inclusions (about 20、30μm). Fatigue striation in fatigue crack growth zone was 1.5~2.0μm in width.