Assessing the hydrogen embrittlement susceptibility of an existing L360NB natural gas pipeline steel for 100 % hydrogen transport

In this study, a section of an existing L360NB natural gas pipeline with a girth weld is sampled to evaluate the hydrogen embrittlement susceptibility upon repurposing for pure hydrogen transport. In various wet and dry hydrogen environments with and without H 2 S, the base and welded material are investigated by constant load tests. The applied load increases hydrogen uptake in the majority of the testing environments. The weld shows a higher hydrogen uptake compared to the base material in all testing environments. In wet H 2 S containing environments under loading, the formed FeS layer helps in reducing the hydrogen uptake. • L360 base and welded material do not fail by HE at 120 bar H 2 . • The addition of 1 bar H 2 S and 5 % NaCl brine also causes no failure. • Dry conditions and wet conditions without H 2 S result in low hydrogen uptake. • The formed FeS layer in the wet H 2 S-containing environments results in reducing the hydrogen uptake with increasing stress.