Susceptibility of Vintage Pipe to Embrittlement in Hydrogen-Natural Gas Blends

Abstract Hydrogen gas is considered as one of promising renewable energy alternatives in the wave of global decarbonation and zero emission. Storage and transporting hydrogen gas impose huge risks in existing pipeline system as result of known hydrogen embrittlement issues with mild carbon steel. Vintage pipe (pre-1970s) typically has higher impurity levels and lower toughness in comparison to the same grade modern steels, so might be expected to have higher susceptibility to hydrogen embrittlement and thus lower pressure/capacity in operation with hydrogen gas or mix of hydrogen and natural gas. In the current work, fracture toughness of a vintage X60 (1971) line pipe material was investigated in a wide range of hydrogen pressures, from 0.5 bara to 100 bara. The J-R curve, initiation toughness and corresponding KJ values are summarized with respect to hydrogen pressures.