Effect of low temperature carburizing on the corrosion and mechanical behavior of AISI 304 austenitic stainless steel after hydrogen charging

Paper in proceeding, 2023

Hydrogen is a clean and renewable energy that could replace fossil fuels, being beneficial to sustainability. Many metallic components in hydrogen energy systems are made from austenitic stainless steels. This research evaluates the effect of hydrogen uptake on the mechanical and corrosion properties of AISI 304 commercial austenitic stainless steel with and without low temperature carburising (LTC) process S³P feat. Kolsterising®. Both solution annealed (SA) and cold worked (CW) conditions were included. Hydrogen was introduced into the steel by the cathodic electrochemical hydrogen charging method. Open circuit potential (OCP) test and potentiodynamic polarisation were employed to evaluate the corrosion resistance in 3.5 wt.% NaCl solution. Specific tensile tests were performed to evaluate susceptibility to hydrogen embrittlement (HE). It has been found that hydrogen uptake causes surface cracking, reduces OCP, corrosion potential, and breakdown potential considerably, accelerating corrosion. LTC samples showed increased OCP and corrosion potential compared to untreated samples after hydrogen uptake. For cold worked 304, LTC treatment improves the resistance to HE significantly due to stabilized austenite and consequently reduced deformation-induced martensite. In solution annealed condition, HE susceptibility was improved slightly by LTC treatment. The results from the current study demonstrated the beneficial effect of this surface engineering approach, i.e., LTC treatment on achieving an improved material performance when exposed to hydrogen.