Abstract
Service failure and many accidents induced by stress corrosion cracking (SCC) frequently occur in the structures made of duplex stainless steel. In this paper, the duplex phase effect on susceptibility of SCC in duplex stainless steel weld metal was discussed analytically by an electro-chemical computer simulation method.
The following properties became evident after examining the analytical results. Susceptibility of SCC became lowest under the condition of α content being nearly 30%, which was closely connected with the transition of weld metal solidification mode. As for the duplex phase effect on susceptibility of SCC, in the case that α content being less than 30%, α phase was found to play an important role of preventing SCC initiation by the so-called keying effect which is caused by the potential deviation toward noble potential. On the other hand, γ phase was simultaneously subjected cathodic protection by α phase. High resistance for SCC of duplex stainless steel was confirmed to be based on the interaction of these phenomena.
