Material Performance of Line Pipe Steels for the Hydrogen Infrastructure

Abstract Since the upcoming hydrogen infrastructure will set high demands on efficient pipelines and thus on the line pipe material as well, test series are presented to investigate in detail the material behavior of typical line pipe steels. Various steels from pipes from different production routes with a range of steel grades from X52 to X70 were selected and tested under gaseous hydrogen. Hydrogen impact on the mechanical behavior of these standard steels is estimated by different test series on base material and weld material. Slow strain rate tests under quasi-static loading are used to evaluate the hydrogen effects on the stress-strain behavior with focus on yield strength, ultimate tensile strength, uniform elongation, and the ductility ratios derived by the comparison of tests performed in hydrogen and inert gas (nitrogen). The materials tested reach high ductility ratios for all steels considered, irrespective of steel grade, production route or microstructure. Further on, the threshold stress intensity factor KIH required in the current ASME B31.12 code is experimentally determined under severe test conditions (high pressure 180 bar). Test procedure, results and validity are evaluated and discussed.