3514 機械構造用材料のフレッティング疲労強度に及ぼす水素ガス環境の影響(S20-3 水素ガス雰囲気での疲労特性,S20 材料強度特性に及ぼす水素の影響)

抄録

The effect of hydrogen gas environment on fretting fatigue strength was investigated. The materials were low alloy steel SCM435H and precipitation hardened stainless steel SUH660, which will be used for hydrogen utilization machines. And the effectiveness of nitriding in hydrogen gas environment was also examined. Hydrogen gas pressure was 0.12MPa in absolute pressure. Fretting fatigue strength of both materials in hydrogen gas was slightly increased than in air. However, in SUH660, fretting fatigue strength in hydrogen gas was decreased than that in air in long-life region. Failure of specimen was caused at approximately 20% lower stress amplitude compared with fretting fatigue limit in air defined as at 3×10^7 cycles. Improvement of fretting fatigue strength by nitriding in hydrogen gas environment was at the same level as that obtained in air.