Microstructure and corrosion behavior of S32101 stainless steel underwater dry and wet welded joints

Abstract

This work focused on the microstructures, secondary phase precipitation and susceptibility to localized corrosion of UNS S32101 duplex stainless-steel welded joints that were welded using underwater dry and wet flux-cored arc welding (FCAW-136). The size and proportion of the austenite phases of the underwater dry welded joints were larger than those of the underwater wet welded joints under the same heat input conditions. In addition, the weld metal exhibited a better resistance to localized corrosion than the heat-affected zone. The high-temperature heat affected zones of the welded joints prepared using underwater dry welding showed improved performance compared with those prepared using underwater wet welding under the same heat input because of the reduced precipitation of chromium-rich nitrides. The resistance to localized corrosion of the low-temperature heat affected zone increased with increasing heat input for the underwater wet welded joints, whereas a reverse trend was observed for the low-temperature heat affected zone of the underwater dry welded joints.