Experimental and Hutchinson–Rice–Rosengren field analysis of J-integral resistance in pre-strained SUS316L at cryogenic temperatures

Large hydrogen storage tanks are often fabricated from metastable austenitic stainless steels, yet residual fracture resistance after pre-straining under cryogenic service conditions is not fully quantified. This difficulty reflects coupled effects of cryogenic temperature, hydrogen environment, and strain-induced martensitic transformation. We introduced pre-strain at ten uniaxial tensile levels and performed 18 compact-tension tests for SUS316L under two cryogenic conditions. Eight conditions were tested at 20 K in liquefied hydrogen, and ten conditions were tested at 77 K in liquefied nitrogen. Fracture toughness decreased systematically with increasing pre-strain at both temperatures. Among the 18 tests, 12 showed significant pop-ins. These were treated according to ASTM E1820 by adopting 𝐽 Q u at the earliest significant event and excluding data acquired after that event from 𝐽 R regression. For trend representation, we employed a modified three-parameter Cosham-type model within an HRR-based framework and calibrated early-stage resistance using 𝐽 Q . The model reproduced the observed pre-strain dependence and provides a quantitative basis for screening and fitness-for-service assessment after severe events in large cryogenic hydrogen storage tanks.