Hideaki Nishikawa

A13 水素ガス中における低炭素鋼S10Cの疲労き裂伝ぱ挙動に及ぼす繰返し速度の影響(A1 材料力学(水素I))

It is necessary to clarify the load frequency and duration time effects on the fatigue crack growth behavior to estimate the fatigue life and strength [1,2]. It has been reported that the fatigue crack growth rate of austenitic stainless steel and aluminum alloy in hydrogen gas environment accelerate at a low test frequency and it saturates below a certain frequency. This tendency is based on the slip-off mechanism of fatigue crack propagation. However, the fatigue crack growth rate of carbon steel in hydrogen gas is more than ten times the rate in nitrogen. The fracture surface in hydrogen gas exhibits quasi-cleavage fracture with brittle striations [3]. It may have another mechanism for the fatigue crack growth [4,5]. Therefore, there is a possibility that the loading frequency effect differs from austenitic stainless steel and aluminum alloy.