Effects of flux cored arc welding parameters on pitting corrosion resistance of duplex stainless steel clad metals

Abstract

Most engineering applications require both high strength and corrosion resistant materials for long reliability and performance. This can be achieved by cladding the surface of steel with a metallurgically compatible corrosion resistant alloy. In recent years, duplex stainless steel has been extensively used for weld cladding. It has excellent pitting and crevice corrosion resistance, high yield strength, good toughness and weldability. During cladding, pitting resistance may be compromised by the formation of intermetallic precipitates, or by excessive precipitation of secondary austenite in the surface regions. Redistribution of alloying elements as a result of such transformations may lead to local reductions in pitting resistance. This may result from the dilution of the filler metal with the base metal and the heat input during cladding. Hence, control of dilution and heat input is very important to maintain the required pitting corrosion resistance. The present paper highlights an experimental study and analysis of various welding parameters influencing PREN and pitting potential in duplex stainless steel cladding deposited by flux cored arc welding (FCAW). Pitting resistance equivalent number (PREN) was found to decrease with increased welding current and welding speed and to increase with increased welding angle and tip to workpiece distance. Pitting potential increased with increased welding current, and tip to workpiece distance and heat input during cladding, and decreased with increased welding speed and welding angle.