Abstract: Duplex stainless steels, especially super duplex stainless steels have very smart corrosion resistance and properties of strength. The pitting corrosion resistance of as welded duplex stainless steels SAF2205 decreased in CPT about 10℃ from that of their base metals. The properties of strength decreased in an acceptable extent, showing good weldability and post pitting corrosion resistance. For the weld of super duplex stainless steel SAF2507, the CPT was as high as that of its base metal, about 65～68℃．The decrease of its properties of strength was very small. The width of its HAZ is rather narrow and the tendency of grain growing was also small, showing remarkable pitting corrosion resistance and weldability. The reason for the change in their properties is studied with chemical composition and microstructure analysis.

Key words: Duplex stainless steel　Butt resistance welding　Pitting corrosion　Property