Stress Corrosion Cracking of Austenitic Type 304 Stainless Steel in Solutions of Hydrochloric Acid + Sodium Chloride at Ambient Temperature

Abstract

Austenitic type 304 (UNS S30400) stainless steel is susceptible to stress corrosion cracking (SCC) in acidic chloride (Cl–) solutions at ambient temperature. In this study, a layer of adsorbed product film enriched in chromium and nickel was found to form on the metal surface in the solutions. This product film had a protective role over the base metal. The nucleation of stress corrosion cracks was connected with the formation of the film and the buildup of a high local concentration of Cl–. Observation by scanning electron microscopy and transmission electron microscopy showed the propagation of stress corrosion cracks was associated with selective corrosion of deformation-induced martensite. The probable mechanism of transgranular SCC in this system was slip dissolution.