The influence of microstructural evolution on selective corrosion in duplex stainless steel flux-cored arc welded joints

The influence of microstructural evolution on selective corrosion in duplex stainless steel flux-cored arc welding joint was investigated by the modified double loop electrochemical potentiokinetic reactivation in acidified chloride. Due to the lower pitting resistance equivalent number, the secondary austenite was preferentially attacked over the ferrite and primary austenite phases, and inclusions acted as nucleation sites for micro-pits in the weld metal. Localised corrosion was generated in the secondary austenite and Cr-depleted zone around the Cr2N and sigma phases in the heat-affected zone. The weld metal exhibited the smallest susceptibility to localised corrosion because of the least weak phases.