Suppression of fatigue crack propagation with hydrogen embrittlement in stainless steel by cavitation peening

In the use of hydrogen energy, the hydrogen embrittlement should be investigated, and it is necessary to improve reliability and safety of machine components which are used in hydrogen environment. The hydrogen sensitivity of material depends on material structure, defect and stress distribution. There is a possibility that the hydrogen invasion into material and the fatigue crack propagation with hydrogen embrittlement can be suppressed by introducing compressive residual stress by using surface modification such as cavitation peening. The cavitation peening is a one of the peening technique, and enhancement of the fatigue strength of the mechanical components and structural materials by cavitation peening have been revealed. In this study, the austenite stainless steel JIS SUS316L with precrack were charged by a cathodic hydrogen charging method, and the fatigue test with and without hydrogen charge were conducted by a plate bending fatigue test. The results demonstrated that the fatigue crack propagation with hydrogen embrittlement can be greatly suppressed by cavitation peening.