Microstructural Investigation of Stress Corrosion Cracking in Cold-Formed AISI 304 Reactor

Abstract

The aim of this study was to investigate cracking behavior of AISI 304 stainless steel that had been exposed to a high temperature MgCl2 solution for several years. The microstructure of the cracked area of the reactor was studied by in-depth microstructural characterization. Transgranular stress corrosion cracking only occurred at the cold-formed part of the reactor. It was observed that approximately 10–20% of the austenite matrix was transformed into alpha prime martensite due to cold forming at the lower head of the reactor. The preferential path for crack propagation was found to be strain-induced alpha prime martensite. The present study reveals that strain-induced martensitic transformation in austenitic stainless steel has a negative effect on stress corrosion cracking.