Discussion on Material Selection of Hydrogen Subsea Pipeline

Aiming at the domestic first hydrogen subsea pipeline, based on the analysis of common hydrogen-induced failure forms and mechanisms, refering to domestic and international relevant standards and codes, and considering the particularity of subsea pipeline installation, the material of hydrogen subsea pipeline is recommended to select using API 5L SPEC X42 and X52 seamless pipes (PSL2 level priority). The heat treatment process of quenching and tempering should be adopted. At the same time, some factors which have influence on hydrogen embrittlement should be controlled, such as the content of alloy elements, carbon equivalent, pipe hardness, non-metallic inclusions and so on. The mechanical properties of pipeline materials can be evaluated by slow strain rate test, fracture toughness test, crack growth rate test, fatigue life test and disk pressure test in the hydrogen environment, so as to judge the hydrogen embrittlement susceptibility of material in hydrogen environment and provide support for practical engineering applications.