Effects of γ， η precipitates and grain size on hydrogen damage (HD) of JBK-75 precipitate-strengthened austenitic steel were examined using the method of high-pressure thermal hydrogen charging and tensile tests. The hydrogen content in the charged specimens was 25.2 wppm. At the condition of η phase-free precipitating, the HD of the steel increased with increasing γ size, fine spherical γ dispersively dis-tributed was beneficial to improve the hydrogen-resistant property. η-phae precipitated at grain boundary increased HD tendency, while intragranular cellular η had less effect on it. Fine austenitic gruin Aize was beneficial to decrease theHD. At the condition of η phase-free precipitating, both hydrogen changed and uncharyed specimens of the steel fractured in ductile transgranular mode, whilst hydrogen promoted the intergranular fracture when obvious η precipitates were found.
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