On the pitting resistance of friction stir welded UNS S82441 lean duplex stainless steel

摘要

Friction stir welding has been considered as an alternative to fusion welding processes of stainless steels. A lean duplex stainless steel, grade UNS S82441, has been recently developed and is prone to localized corrosion, such as pitting when exposed to harsh conditions during use. However, pitting resistance of UNS S82441 has not been previously investigated. In this study, UNS S82441 lean duplex stainless steel was friction stir welded, and its microstructure and localized corrosion resistance were investigated by phase volumetric fraction, scanning electron microscopy, transmission electron microscopy and electrochemical tests. The pitting resistance of each zone was investigated by polarization tests and by determining the critical pitting temperature. The results indicated that microstructural changes promoted by friction stir welding affected the pitting resistance of the lean duplex stainless steel.