Investigating the Fracture Properties of 316 Stainless Steel

Austenitic stainless steel 316's role in industrial applications has spurred extensive but fragmented studies, presenting challenges in synthesizing its diverse properties. This study comprehensively investigates its fracture properties, analyzing the interplay of mechanical traits, microstructural nuances, strain rates, operational temperatures, hydrogen and helium impacts, heat treatment effects, and fracture behaviors across varying operational parameters. Analysis reveals a robust correlation between microstructure and mechanical characteristics, specially yield stress and fracture topography. Predictive models like Hall-Petch equation and Gibson-Ashby micromechanical model adeptly project these mechanical attributes. Deformation strain-rate surpasses relative porosity density in impact. Higher relative density prompts increased slip bands and grain deformation at constant strain rates, indicating local shear as the primary fracture mode, evident from observed shear bands. Hydrogen's influence, though delayed, assumes a secondary dominant deformation mechanism. While low strain rates do not alter failure modes due to hydrogen damage, its primary impact lies in reducing stress required for dislocation displacement and crack propagation, thereby diminishing tensile strength. External hydrogen exhibits a pronounced effect in some instances. Heat treatment significantly modifies the ferrite-cementite phase interface, impacting fracture morphology, notably at higher temperatures. Controlled annealing enhances fracture resistance at the expense of potential strength reduction, necessitating cautious execution due to heightened hydrogen embrittlement risk from reduced grain boundary chromium. This study seeks to consolidate insights into 316 SS fracture behavior, offering future research directions and practical implications for optimizing its performance in varied industrial settings.