Effects of Shot Peening on SS304 Fatigue Performance: Residual Stress Relaxation and Life Prediction Modeling

In this study, the shot peening–induced residual stress relaxation process of specimens machined from SS304, a commonly used austenitic stainless steel in engineering, with various shot peening intensities (0.1, 0.25, and 0.4 mmA), was characterized. Then, the surface morphological distortion against enhanced peening intensities was also tested and analyzed with the 3‐D white light interferometer and finite element method. Finally, a novel life prediction model considering the residual stress relaxation process and fatigue failure process of shot‐peened specimens was constructed, which presented satisfied life prediction results regarding specimens with different shot peening intensities subjected to various cyclic mechanical loads. The newly proposed life prediction model in this study indicates that shot peening process has both advantages and disadvantages on fatigue performance, where, more specifically, shot peening process is truly beneficial to fatigue performance when the applied mechanical load is inconsiderable, while shot peening process is harmful to fatigue performance when the load is considerable.