Droplet transfer during conventional gas metal arc and plasma-gas metal arc hybrid welding with Al 5183 filler metal

When welding with 5xxx series aluminium filler wires, explosion of droplets occurs during droplet transfer, which results in spatter formation. In plasma-GMA (gas metal arc) hybrid welding, the coaxial plasma arc surrounding the GMA enables more stable droplet transfer and lower GMA current. In this study, bead-on-plate welding tests were conducted using conventional GMA welding and plasma-GMA hybrid welding. Droplet transfer behaviours for both processes were observed using high-speed imaging, and droplet explosion behaviour was analysed under various welding conditions. In plasma-GMA welding, the droplet transfer was stabilized without in-flight explosion, even for high welding current and higher melting rate was achieved by the additional plasma arc. (C) 2012 Elsevier B.V. All rights reserved.