Abstract
The pulsed gas metal arc welding (GMAW-P) process has many attractive features as it allows control of the current waveform. The performance of the alternating current (AC) version of the GMAW-P (henceforth GMAW-AC) process applied to the welding of aluminum plates in overlapped joints with a variation in the root opening between the sheets will be analyzed and discussed in this article, as the welding involved process phenomena. For comparison, in this study, the more usual direct current (DC) version of this process was employed. In addition to evaluating the root opening performance of each modality and the effect of negative polarity on the welding, the behavior of the geometric interactions of the wire, arc, and molten pool were addressed and evidenced through high-speed filming. It was possible to clearly observe the main effects of negative polarity on the electrode wire, such as the arc climbing on the wire, and also the influence on the formation and morphology of the weld bead. Results showed that both versions of the GMAW process were able to fill gaps of up to 2.0 mm, but, with regard to avoiding melt-through of thin aluminum sheet, the AC modality presented a significant advantage.
Reference:
ROSA, A. F.; CIRINO, L. M.; NOGUEIRA. R. R.; SCHWEDERSKY, Mateus B.; MARQUES, C.; SILVA, Regis H. G.. Root Opening Performance and Geometric Weld Features in GMAW-AC. Welding Journal, v. 101, n. 3, p. 62-67, 2022.