抄録
A study has been made on the influence of hydrogen on fatigue crack initiation and propagation of SNCM420 steel with special interest on the role of internal defects. Fatigue fracture under hydrogen attack starts at the surface of specimen when fatigue test were carried out under relatively higher stress amplitude while the fatigue fracture starts at internal defects when stress amplitude is relatively lower than fatigue limit of the material. It may be also concluded that hydrogen degradation in low stress fatigue can be explained from the possible accumulation of hydrogen damage during loading period.
