Quantifying the hydrogen embrittlement of pipeline steels for safety considerations

In a near future, with an increasing use of hydrogen as an energy vector, gaseous hydrogen transport as well as high capacity storage may imply the use of high strength steel pipelines for economical reasons. However, such materials are well known to be sensitive to hydrogen embrittlement (HE). For safety reasons, it is thus necessary to improve and clarify the means of quantifying embrittlement. The present paper exposes the changes in mechanical properties of a grade API X80 steel through numerous mechanical tests, i.e. tensile tests, disk pressure test, fracture toughness and fatigue crack growth measurements, WOL tests, performed either in neutral atmosphere or in high-pressure of hydrogen gas. The observed results are then discussed in front of safety considerations for the redaction of standards for the qualification of materials dedicating to hydrogen transport.

► Necessary to improve the means of quantifying hydrogen embrittlement of pipelines.
► Many experimental ways to address hydrogen embrittlement.
► Definition of associated embrittlement indexes.
► Addressing the sensitivity of each index in terms of embrittlement mechanisms.
► Need for improved standards and codes for hydrogen transportation.