Effects of hydrogen pressure and test temperature on fatigue crack growth rate of SM490B and SCM435

Abstract

In order to investigate the effects of hydrogen gas pressure and temperature on fatigue crack growth characterizations of low carbon steel JIS-SM490B and low alloy steel JIS-SCM435, fatigue crack growth tests using a CT specimen were conducted in pressurized gaseous hydrogen in various temperature. In low-pressure hydrogen gas, the fatigue crack growth rate was decreased with increasing of temperature. On the other hand, in high-pressure hydrogen gas, the fatigue crack growth rate was not depending on temperature. The mechanism of fatigue crack growth under hydrogen environment with various temperature and pressure was discussed based on the theory of dislocation trapping of hydrogen.