The effect of carbon on hydrogen embrittlement in stable Cr-Ni-Mn-N austenitic stainless steels

The effect of carbon on hydrogen embrittlement in stable austenitic stainless steels is investigated by adding either 0.02 or 0.1 wt.% C. During deformation, planar slip is pronounced and fine dislocation structures develop, which is followed by mechanical twinning in both steels. After hydrogen pre-charging, the alloy with higher carbon is more susceptible to hydrogen embrittlement. Based on strain hardening behaviour, it is proposed that C enhances planar slip and refines mechanical twins. Therefore, a higher C concentration results in more sites available for stress concentration and hydrogen trapping, and accelerates the embrittlement.