The effect of low hydrogen content on hydrogen embrittlement of additively manufactured 17–4 stainless steel

Abstract

This work aims to evaluate the impact of small amounts of hydrogen on the hydrogen-assisted cracking (HAC) of 17-4 martensitic stainless steel (SS) prepared by additive manufacturing (AM). To elucidate the effect of processing on the hydrogen–material interactions, the obtained results were compared with a conventionally manufactured (CM) counterpart. It was found that the hydrogen uptake of AM 17-4 SS is higher compared to CM; however, its resistance to HAC is improved. These differences are attributed to the presence of stronger hydrogen trapping sites, retained austenite and the absence of Nb-rich precipitates in the AM 17-4 SS. The effect of processing on the microstructure and the susceptibility to hydrogen-induced damage and hydrogen embrittlement is discussed in detail.