Threshold Strain and Cyclic Stress Effects on Stress Corrosion Cracking of Duplex Stainless Steel 2205 in Chloride Environment and White Liquor

Abstract

The stress corrosion crack initiation and the effect of cyclic stress on Stress Corrosion Cracking (SCC) of Duplex Stainless Steel (DSS) 2205 in concentrated chloride solution and caustic White Liquor (WL) were investigated. The threshold stress/strain for stress corrosion crack initiation of DSS 2205 was determined in the chloride and WL environments. Low frequency cyclic tests were performed and stopped after certain cycles, and the crack initiation events were examined after these tests. In concentrated chloride solution, corrosion pits are the preferential sites for crack initiation of DSS 2205 under cyclic loading. In WL environment, precipitates tend to be the preferential sites for cracks to initiate, especially the ones at or near the interface of the phase boundary and grain boundary.