Effects of Hydrogen on Fatigue Life Properties of Cold-Rolled Metastable Austenitic Stainless Steels With Artificial Defects

It is important to understand the effect of hydrogen on the fatigue properties of materials to ensure the safety and reliability of hydrogen components. In this study, a cold-rolled metastable austenitic stainless steel, JIS-SUS301, with a tensile strength of around 1.3 GPa was prepared and subjected to plane-bending fatigue tests in air at room temperature by using uncharged and H-charged plate specimens with a thickness of 2 mm. A drilled hole or a sharp notch was introduced at the center of the plate specimens to control crack initiation sites. The H-charged specimens were exposed to 100 MPa hydrogen gas at 270°C for 200 h. The results showed that in high-stress amplitude regimes, the fatigue life of the specimens with a drilled hole or a sharp notch was significantly degraded by hydrogen. In contrast, the fatigue limit of the specimens with a drilled hole, which was determined by the critical stress for crack initiation, was not degraded by hydrogen, or was slightly raised, while the fatigue limit of the specimens with a sharp notch, which was determined by the threshold stress for crack propagation, was not affected or was only slightly degraded by hydrogen. Although the effect of hydrogen on the fatigue limit differed between the drilled hole and sharp notch, the difference was not significant.