Abstract
In the near future, hydrogen energy is expected to become a practical energy source. However, it is known in previous studies, that steels become brittle and fractures early in hydrogen environment. This phenomenon is called hydrogen embrittlement, and it has become a problem for hydrogen energy to become a practical energy source. In order to prevent hydrogen embrittlement, it is necessary to understand fatigue crack growth behavior in hydrogen environment. Thus in this study, we conducted crack growth analysis using the value of hydrogen concentration obtained by hydrogen diffusion analysis. The objective of this analysis is to investigate the effect of work hardening coefficient on crack growth behavior in hydrogen environment. As a result, it is found that the hydrogen concentration around a crack tip with higher work hardening coefficient is higher than that with lower work hardening coefficient. This phenomenon cased the increase of acceleration rate of fatigue crack growth rate in hydrogen environment. These results showed that the material which has low work hardening coefficient have a resistance for hydrogen embrittlement at the crack growth process which is different from that of a notched specimen.
