Abstract: In view of the 38Si7 spring steel of industrial production with fatigue failure, using optical microscopy and scanning electron microscopy, combined with mathematical theoretical models, the reason of 38Si7 spring steel with fatigue failure was analyzed from the perspective of inclusion. The results show that the inclusions in 38Si7 spring steel of industrial production is mainly composed of CaO(MgO)Al2O3SiO2 ternary complex inclusions, and the Al2O3 composite contents of complex inclusion in the central region of round cross section are significantly lower than the outer layer. According to the projected area equivalent inclusion model, when the fatigue failure is from an internal crack, the critical inclusion size is approximately 6.5μm; when the fatigue failure is from the surface crack, the critical inclusion size is approximately 5.5μm. When the inclusion size in the spring steel is larger than the critical size of inclusions, the probability of fatigue failure will increase.
张宏亮,冯光宏,贾志立. 疲劳性能不合格的38Si7弹簧钢夹杂物分析[J]. 钢铁, 2011, 46(5): 85-88.
ZHANG Hongliang,FENG Guanghong,JIA Zhili. Analysis of the Inclusions in 38Si7 Spring Steel With Fatigue Failure. Iron and Steel, 2011, 46(5): 85-88.