Improving the high-cycle fatigue life of a high-strength spring steel for automobiles by suitable shot peening and heat treatment

ABSTR A C T Shot peening (SP) treatment is a common and useful method that can affect the fatigue life of metallic com-ponents. In this work, the high-cycle fatigue (HCF) lives of 50CrMnMoVNb spring steels with different SP in-tensities and conditions were investigated. Meanwhile, the differences in the microstructures and crack initiation sites were compared. The fatigue life of the investigated steels is greatly improved via suitable heat treatment. Furthermore, SP treatment is beneficial to the improvement of the fatigue life of heat-treated specimens with higher strength, and the optimal SP intensity is 0.15 ~ 0.25 mmA. However, SP deteriorates the HCF life of the as-received specimens with lower strength. This study can enrich the fundamental knowledge on how to improve the HCF life of spring steels and provide new ideas about the influence of different SP intensities on the surface layer and fatigue properties.