Comparison of tensile properties of X60 pipeline steel tested in high pressure gaseous hydrogen using tubular and conventional specimen

Developing engineering standards for the hydrogen economy requires extensive materials testing at relevant operating conditions, i.e. in gaseous hydrogen at various pressures and temperatures. One method to satisfy the need for a high and affordable output of test results is materials testing using tubular specimens where the hydrogen pressure is applied inside the tube. This study focused on the comparison of tensile properties of X60 pipeline steel tested in high pressure gaseous hydrogen using tubular (TS) and conventional specimen (CS) tested in an autoclave. The reduction of area (RA) of TS showed comparable trends known from literature for CS upon a variation of strain rate and residual oxygen content. However, when the identical X60 steel was tested in ambient air, RA of the TS was lower compared to the CS. When tested in hydrogen, RA of the TS is higher compared to the CS. Both could be interpreted and explained by differences in the necking behavior, with and without hydrogen.