Effect of post-weld heat treatment on microstructure evolution and pitting corrosion behavior of UNS S31803 duplex stainless steel welds

Abstract The effect of tungsten inert gas welding and subsequent post-weld heat treatment on the microstructure evolution and pitting corrosion behavior of duplex stainless steel UNS S31803 was investigated. Detailed microstructure examination demonstrates that ferrite presents higher volume fraction and is easier to suffer attack of pitting corrosion than austenite in the welded zone of as-welded metal. After post-weld heat treatment, the volume fraction of austenite in the heat affected zone and weld metal is elevated significantly. The highest pitting corrosion resistance is obtained at 1080 °C with the highest critical pitting temperature and pitting nucleation resistance.