3511 SUS310S鋼の疲労き裂伝ぱ速度に及ぼす水素雰囲気の影響およびその周波数依存性(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)

Abstract

In order to investigate whether hydrogen enhance the fatigue crack growth (FCG) rate of stable austenitic stainless steels or not, FCG tests of a type 310 steel were performed in a hydrogen gas environment and in a nitrogen gas environment. The FCG rate tested at 5.0Hz in hydrogen is higher than that in nitrogen. It seems that the acceleration of FCG rate in hydrogen does not necessarily need the formation of strain-induced α' martensite, though it increases the degree of the acceleration. The cause of the acceleration of type 310 seems to be hydrogen enhanced concentration of slip at a crack tip. The degree of the acceleration became smaller in a frequency of 0.1Hz. It seems that the generation of heat at the crack tip concern. Further investigation is necessary.