Effect of Heat Input and Shielding Gas Mixture on the Microstructure of Super Duplex Stainless Steel Welds

Abstract

Duplex stainless steels find ever-increasing applications in chemical, off-shore, paper/pulp and fertilizer industries owing to their excellent combination of mechanical and corrosion properties [1-3]. More demanding situations prefer super duplex stainless steels, which have higher pitting resistance equivalence [4]. Even though many of the conventional welding processes are employed for joining of these high-performance materials, still the industries face the problem of achieving the desired properties - especially the corrosion resistance, in the resultant weldments [5-7]. Welding upsets the ferrite-austenite microstructural balance in the weld metal and in the high temperature heat affected zone. More so, industrially different gas/gas mixture combinations are employed for achieving the desired properties [8-10]. In the current work an attempt has been to study the effect of different welding processes on weld metal microstructure in the super duplex stainless steel grade SAF 2507.