Fatigue properties of soluted and sensitized SUS 304 stainless steel have been investigated in high pressure hydrogen up to 4.02MPa and atmospheric argon at room temperature. The results obtained are as follows:
(1) The number of cycles to failure of both the soluted and the sensitized steel decreased with increasing hydrogen pressure. Large decrease was observed on the sensitized steel in comparison with the soluted steel.
(2) The fatigue limits of the soluted and the sensitized steel decreased with increasing hydrogen pressure. Little difference was observed on the fatigue limits between the soluted and the sensitized steel.
(3) Typical fatigue fracture modes were observed on the fracture surface in fatigue crack growth area (Area II) depending on the type of gas, that is argon or hydrogen. In this area, striations were observed on the surface fractured in argon and brittle transgranular fracture in hydrogen.
