Microstructural and electrochemical behavior of 2205 duplex stainless steel weldments

The paper describes the joining of rolled plates of 2205 Duplex stainless steel (DSS) by Gas tungsten arc welding (GTAW) and shielded metal arc welding (SMAW). The development of different phases upon welding without any post heat-treatment - especially in the heat affected zone (HAZ) - and their consequent different corrosion resistance were investigated through optical microscopy, scanning electron microscopy (SEM), X-ray diffraction (XRD) method and potentiodynamic Tafel scan in aqueous NaCl solution. Comparison of mechanical properties and fracture surface morphology of the welded joints were also made. GTAW weldment was found more effective towards corrosion resistance due to the presence of relatively larger amount of secondary austenite (γ2) i.e. acicular austenite in HAZ - when compared with the HAZ of SMAW.