A review on factors affecting cryogenic mechanical properties of austenitic stainless steel weld metal

With the development of cryogenic environments down to 77 K, cryogenic engineering has put forward increasingly stringent requirements for mechanical properties of austenitic stainless steel welded joints. Cryogenic strength, impact toughness and resistance to hydrogen embrittlement of weld metal have become critical components for ensuring secure operation in such circumstances. Therefore, influence of cryogenic temperatures on impact toughness and strength of austenitic stainless steel weld metal and two behaviors of hydrogen embrittlement caused by varying temperatures were discussed in this research. Additionally, effects of ferrite phase, martensitic phase transformation and nitrogen content on low temperature strength of weld metal was introduced, as well as these factors, precipitates and inclusions further reducing impact toughness at low temperature. Then, it also explored remarkable stability of austenitic phase in weld metal, emphasizing its resilience to both favorable consequences of hydrogen embrittlement and unfavorable impacts of ferritic phase. Multiple factors simultaneously affected the performance of weld metal in practical applications. In turn, investigating these variables’ effects on different attributes could improve safety of austenitic stainless steel weld metal in cryogenic conditions.