3504 ステンレス鋼微小予き裂材の疲労強度に及ぼす水素チャージの影響(S20-2 水素チャージ材の強度特性,S20 材料強度特性に及ぼす水素の影響)

抄録

Absorption of hydrogen into the material might be occurred during long-term operation when the hydrogen utilization machines are used in the high-pressurized hydrogen gas. Therefore, investigation of fatigue strength properties of hydrogen charged materials is important. And the effect of hydrogen on fatigue strength might be different depending on the material hardness. In this study, highly work-hardened stainless steel SUS304 was used for fatigue test. Micro fatigue crack, which depth was 25μm was introduced to the fatigue specimen as initial defect. And smooth specimen was also used. Hydrogen charge was done by cathodic charge method before fatigue test. Fatigue strength of pre-cracked specimen was significantly reduced by hydrogen pre-charge. Crack propagation rate was increased and ΔK_<th> shows a trend to reduce. There was little effect of hydrogen pre-charge on fatigue strength of the smooth specimen.