To extend the lifetime and enhance the safety level of aging pressurized equipment, it is vital to develop improved methods for assessing the fatigue life of austenitic stainless steel, which is a highly ductile material used for equipment and structural components in nuclear power plants. Shot peening is one of the most promising methods for increasing the lifetime of welds and other components that are subject to regular plant inspections. In this study, the effect of peening with Zr shot of varying size on fatigue crack growth and crack opening behavior in notched specimens was investigated. Large-diameter shot that could still reach the notch tip was effective at reducing both fatigue crack occurrence and the width of fatigue crack openings. This benefit was highest at low applied loads. However, once a crack had occurred, Large-diameter shot was effective at increasing the crack growth rate.
