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 H2S, 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 H2S containing en- vironments under loading, the formed FeS layer helps in reducing the hydrogen uptake.