Effect of Micro-Shot Peening on the Fatigue Performance of AISI 304 Stainless Steel

The effects of micro-shot peening on the rotating bending fatigue resistance of AISI 304 stainless steel (SS) were investigated in this study. The strain-hardening, surface roughness and induced residual stress were inspected and correlated with fatigue strength. Micro-shot peening caused intense strain-hardening, phase transformation and residual stress but was also accompanied by a minor increase in surface roughness. A nanograined structure, which was advantageous to fatigue resistance, was observed in the severe shot-peened layer. The absence of microcracks, minor increase in surface roughness, nanograined structure and induced high compressive residual stress in the shot-peened layer were responsible for the improved fatigue strength of AISI 304 SS.