Comparative study on the effects of Cr, V, and Mo carbides for hydrogen-embrittlement resistance of tempered martensitic steel

In this study, the ideal alloying element (among Cr, V, and Mo carbides) to enhance the resistance to hydrogen embrittlement (HE) in tempered martensitic steel was investigated. Four types of steels were designed to contain cementites, Cr-rich M3C, V carbides, and Mo carbides, respectively, tailored to possess comparable tensile strength (-1.6 GPa). The HE resistances of these steels were evaluated through slow strain rate and cyclic corrosion tests. Results displayed enhanced HE resistance in samples with V and Mo carbides, with Mo carbide being the most effective, attributed to its high resistivity, inhibited hydrogen penetration, and suppression of strength loss due to internal hydrogen. This research highlights growing trends in the steel industry towards high-strength materials, emphasizing the significance of understanding HE challenges in tempered martensitic steels. Despite importance, limited research has focused on carbide compositions' impacts on HE properties in these steels, thus underlining the necessity for further investigation to exploit V carbides' hydrogen-trapping capabilities and their effects on overall HE resistance.