The elastic-plastic fracture toughness and fatigue crack growth properties of the soluted and the sensitized SUS 304 stainless steel were investigated in high pressure hydrogen at room temperature.
The results obtained are as follows;
(1) J1H value of the sensitized SUS 304 was smaller than that of the soluted one and both of them decreased with increasing hydrogen pressure.
(2) On the fracture surface of the sensitized SUS 304 fractured in hydrogen, the brittle and transgranular fracture as well as the intergranular fracture were observed, but no streched zone was observed. For the soluted one, only the brittle and transgranular fracture was observed.
(3) The fatigue crack growth rate of SUS 304 in hydrogen was larger than that in argon for both the soluted and sensitized ones. The hydrogen susceptibility of the sensitized SUS 304 was larger than that of the soluted one.
(4) The brittle and transgranular fracture was mainly observed on the soluted SUS 304 and the intergranular fracture was observed on the sensitized one in the fatigue tests under high hydrogen pressures.
