Effect of Alloying Elements in Electrode Wires on Gas Metal-Arc Welding of Aluminum

Abstract

Using six series of aluminum-alloy electrode wires, bead-on-plate specimens were made in Ar-N₂ mixed gas atmospheres. The effects of titanium, zirconium, silicon, copper, zinc and magnesium in electrode wires on the surface appearance, depth of penetration, porosity and nitrogen content of weld metals were systematically studied.
The main results obtained are as follows:
(1) Al-Ti, Al-Zr, AI-Si and Al-Cu wires are prone to cause puckered welds at PN₂=0.1-0.5 atm (PAr=0.9-0.5 atm).
(2) Zinc and magnesium are effective alloying elements to prevent puckering phenomena in Ar-N₂ atmospheres.
(3) Use of Al-Zn and Al-Mg wires gives rise to good profiles of penetration even in nitrogen- rich Ar-N₂ atmospheres.
(4) Use of Al-Ti, Al-Zr, Al-Si and Al-Cu wires increases the porosity of aluminum welds in Ar-N₂ atmospheres.
(5) The nitrogen content of weld metals decreases with increasing Ti, Zr, Si, Cu, Zn and Mg contents in electrode wires.
(6) From the view point of welding process, Al-Zn or Al-Mg electrode wires are fit for the Ar-N₂ gas metalarc welding of aluminum.