Comparison of hydrogen effects on additively manufactured and conventional austenitic steels

• In-situ testing of hollow specimen in gaseous hydrogen at slow strain rates. • Comparison of additively manufactured and conventional austenitic stainless steel. • Hydrogen enhanced degradation is shown for every tested material, most severe in 304L. • Similar to higher loss of ductility is shown for PBF-LB/M 316L compared to conventional 316L. Hydrogen and its derivatives are promising energy carriers for future renewable energy supplies. Austenitic stainless steels, such as AISI 316L, are commonly used in hydrogen transportation systems. While often thought to be resistant to hydrogen embrittlement, studies have shown that 316L is susceptible under certain conditions. As demand for hydrogen applications grows, additive manufacturing (AM) technologies offer design flexibility and customisation benefits. However, data on AM parts behaviour in hydrogen environments is lacking. This study investigates the influence of hydrogen on mechanical properties using slow strain rate testing (SSRT) on conventional AISI 304L, 316L and AM 316L specimens. The results indicate a greater effect of hydrogen on 304L compared to 316L, with AM 316L showing increased susceptibility. However, the ductility of AM 316L remains comparable to conventional 316L due to its initial ductility. The study provides insights into the performance of conventional and AM austenitic stainless steels in gaseous hydrogen environments.