Sensitization and Stress Corrosion Crack Response of Dual Certified Type 304/304L Stainless Steel

Abstract

Sensitization has previously been implicated in the stress corrosion cracking (SCC) susceptibility of carbon-containing Type 304 stainless steel (SS) in oxygenated water. Thus, Type 304L SS, with low carbon content, is expected to be resistant to sensitization and therefore SCC susceptibility. The current work evaluates the SCC response of two heats of dual certified Type 304/304L SS that exhibit different microchemical characteristics. One heat contains elevated boron content, while the other heat has delta ferrite stringers in the matrix. It is shown that both heats can be susceptible to SCC because of their unique microchemical features under certain combinations of heat treatment, water chemistry, and deformation level, while under other conditions they remain relatively resistant to SCC.