Influence of Heat Input on Corrosion Resistance of Welded UNS S32205 Investigated By EIS

The corrosive behavior of the UNS S32205 duplex stainless steel (DSS), as base metal and welded by the welding of inert gas of tungsten (IGT) process with pulsed current, was investigated using different heat inputs. The corrosion evaluation was performed by means of electrochemical tests such as Potentiodynamic Polarization and Electrochemical Impedance Spectroscopy in a solution of 3.5% NaCl. The change in microstructure was visualized by optical microscopy revealing the presence of metastable pits that did not have the time or the favorable conditions for growth. The results indicate that welding processes with higher heat inputs generate a lower cooling rate in the welding region, guaranteeing a higher austenite phase precipitation, making the microstructure more balanced, thus increasing the corrosion resistance compared to samples welded with lower heat inputs.