Fatigue and fracture of three austenitic stainless steels at cryogenic temperatures

Abstract

For the past couple decades, 316LN stainless steel has remained the "go-to" alloy for structural components intended for cryogenic temperature service, partially because of its favorable mechanical properties, but also because of the data available in the literature for T = 4 K. In recent years, some interest has arisen to investigate and develop stronger and tougher alloys for cryogenic structural components, particularly for magnet systems like ITER. This study presents new 4 K fatigue crack growth rate (FCGR) and fracture toughness data for Nitronic® 50 and JK2LB stainless steels, compiles existing data for these alloys, and compares them with 316LN data found in literature. This study intends to further expand the existing cryogenic data set for these alloys, clarify key differences between them to better facilitate mechanical design, and potentially bolster further alloy development.