On the stress corrosion crack initiation behaviour of Alloy 800 in high-temperature hydrogenated water

The stress corrosion cracking (SCC) initiation behaviour of annealed Alloy 800 was studied in high-temperature hydrogenated water through slow strain rate tensile (SSRT) test. The results indicate that Alloy 800 exhibits higher SCC initiation resistance than 304 stainless steel (SS), with a comparable length percentage of grain boundary surface cracking but much shallower crack depth. The higher SCC resistance of Alloy 800 is primarily attributed to its higher Cr content, which enhances the alloy's resistance to intergranular oxidation. However, Alloy 800 is still susceptible to SCC initiation, as most high-angle grain boundaries are prone to penetrative oxidation.