Effect of dynamic wire in the GTAW process: Microstructure and corrosion resistance

:: The final publication is available at link: https://doi.org/10.1016/j.jmatprotec.2020.116758

Experimental tests were carried out to evaluate and compare welding bead characteristics depending on wire’s oscillation frequency in the GTAW with dynamic wire feeding. Two constant currents (200 A and 250 A) and three frequencies (0 Hz, 5 Hz and 18 Hz) were used to lay an Inconel 625 filler metal over ASTM A36 steel substrates. The weld metal microstructure analysis was based on Scanning Electronic Microscopy (SEM) and the corrosion performance was assessed by means of the Cyclic Potentiodynamic Polarization method. As main results, the increase in wire’s frequency tends to promote more convex welding beads and a 22 % reduction of dilution, in addition to a higher spreading (and higher isotropy) of the precipitates in the material’s structure. For the high energy condition (250 A) the highest frequency also increased significantly the welding bead corrosion resistance. However, for 200 A cases the effect of the wire’s oscillation in the dilution and bead’s reinforcement was not so pronounced, although with higher frequency a greater spreading in phases precipitated was verified.
Keywords: TIG wire oscillationWire pulsationWire vibrationNickel-based alloy weld metallurgyPrecipitates spreading

RIFFEL, K. C.; SILVA, R. H. G.; HAUPT, W.; SILVA, L. E.; DALPIAZ, G.. Effect of dynamic wire in the GTAW process: Microstructure and corrosion resistance. Journal of Materials Processing Technology (2020), doi.org/10.1016/j.jmatprotec.2020.116758