Deformation Microstructures of Austenitic Stainless Steels - Reduced Amount of Nickel and Molybdenum for Hydrogen Energy Systems

High pressure gaseous hydrogen is regarded as one of the effective means of energy transportation and storage. To confirm the compatibility of newly developed austenitic stainless steels with reduced amount of nickel and molybdenum for hydrogen energy systems, tensile properties were evaluated in high pressure gaseous hydrogen and helium up to 90 MPa and in air at room temperature. Elongation of new austenitic stainless steels "STH1" increased with increasing the hydrogen and helium pressure up to 90 MPa than in air. The deformation microstructure of STH1 after tensile test in gaseous hydrogen and helium was closely observed by transmission electron microscope. The effect of twinning induced plasticity on high pressure gaseous hydrogen and helium is discussed.