Effect of main arc voltage on arc behavior and droplet transfer in tri-arc twin wire welding

Abstract

Increasing the weld deposition rate invariably increases the welding heat input in monofilament arc welding or high efficiency twin wire arc welding and hence cannot be easily optimized to satisfy the needs of special applications requiring high weld deposition. Tri-arc twin wire welding using direct current pulse power supply and variable polarity power supply is proposed. This helps reduce the welding heat input in the work-piece and increase the deposition rate. With increasing the main arc voltage, the droplet transition changed from an unstable mixing transition to a stable repulsion particle transition. In addition, the main arc voltage was increased to 35 V, three arcs could be observed simultaneously. The main arc pulse, when switched on, changed the M arc, arc force, spot force, and plasma flow force. These changes hampered the balance of the original force system and promoted the generation of welding spatter. It may be noted that a sufficient main arc welding voltage can provide appropriate process stability. The third arc provided an additional separation force for the wire droplets and promoted the droplet transfer.

Keywords

• Tri-arc
• Twin-wire
• Heat input
• Droplet transfer
• Arc behavior