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Weld bead characteristics in pulsed GMA welding of Al-Mg alloys

Publisher : Welding Journal (Miami, Fla)

Year : 1999

Abstract : The object of this investigation was to determine a suitable pulse parameter combination to obtain good-quality welds for a given weld bead size. Weld bead characteristics have been influenced by the parameters of pulsed current, i.e., peak current (IP), peak duration (TP), background current (IB) and background duration (TB). The effect of pulsed current parameters on gas metal arc (GMA) weld bead geometry was studied, and a single diagram in the non-dimensional form was developed, representing many aspects of weld bead characteristics. This diagram was then used to select the most suitable combination of GMAW-P parameters for a given weld bead size in the welding of a 6-mm (0.236-in.) thick AA 5083 Al-Mg alloy base metal, using 1.2-mm (0.047 in.) diameter ER 5356 filler metal. The correlation of the cross-sectional area of penetration, total cross-sectional area of weld and nondimensional width of weld bead with operating parameter `n' (a nondimensional heat input rate that governs the dimension of the weld pool) was obtained. Nondimensional terms were used to plot the results for all materials and welding variables on a single diagram, with many aspects of plate fusion behavior represented on a single graph.

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