Effect of cryogenic temperatures on the mechanical behavior and deformation mechanism of AISI 316H stainless steel

Abstract

AISI 316H stainless steel, which is a type of cryogenic temperature steel, has excellent potential in the cryogenic engineering field. However, its performance at cryogenic temperatures, especially its mechanical properties, has not been adequately investigated. This study investigates the quasi-static mechanical behavior and strengthening mechanism of 316H at cryogenic temperatures using uniaxial tensile testing. The dynamic mechanical behavior and strengthening mechanism were initially investigated at different temperatures and strain rates using the Split-Hopkinson pressure bar (SHPB) test. During quasi-static deformation at decreasing temperatures, the yield strength and tensile strength increased significantly and the elongation decreased. Additionally, martensitic transformation was observed at temperatures below −120 °C, which is the main cryogenic temperature strengthening mechanism. During the SHPB test, the flow stress increased as the temperature and strain rate decreased and increased, respectively. The strain rate and temperature sensitivity factors were negatively correlated with temperature, and the cryogenic temperature had a significant strengthening effect. A modified Johnson-Cook constitutive model, which considers the effect of cryogenic temperatures, was established to describe the mechanical properties of 316H over a wide range of temperatures and strain rates.