Comparison of hydrogen resilience of three different corrosion-resistant martensitic steels

• Strongest H trapping in N-alloyed martensitic steel related to M23(C,N)6 precipitates. • Slightly weaker trapping in dual hardening Hybrid60, mostly at M23C6. • Primary carbides/carbonitrides act as crack initiation in N-alloyed and high-C steels. • Dual hardening Hybrid60 performed best in H charged slow strain rate testing. • High-C steel performed worst regarding mechanical strength and H/D retainment. Hydrogen gas is a critical resource for future sustainable energy production, with stainless steels playing a substantial role in applications where components are exposed to hydrogen gas environments. In this work, the resistance to hydrogen embrittlement of three ultra-high strength martensitic stainless steels was investigated. The materials comprised of one high carbon, one nitrogen-alloyed and one dual precipitation hardened steel. The experiments involved a combined deuterium charge, followed by atom probe tomography, and hydrogen gas charge, followed by slow strain rate testing. This approach enabled the study of each steel’s resilience to hydrogen gas and allowed correlations between mechanical behaviors after hydrogen charging and their hydrogen trapping capabilities, as well as the presence of undissolved primary carbides or carbonitrides. Results showed that while the nitrogen-alloyed stainless steel demonstrated the highest hydrogen trapping capability, the presence of undissolved primary carbides or carbonitrides within it served as crack initiation sites during slow strain rate tests, reducing its hydrogen resistance. The dual precipitation-hardened steel, which lacked undissolved carbides, exhibited the least hydrogen embrittlement.