ABSTRACT
This chapter presents the developments in multiple-wire welding from the technology and research perspectives. The multiple-wire welding uses more than one electrode, in which the electrodes travel simultaneously with the same or different feed rates through a joint contact tube. The twin-wire welding is the most investigated and frequently used variant of the multiple-wire technology. In twin-wire welding, the two wires are positioned in-line or at any angle across the seam with a single or multiple power sources. One of the significant developments in twin-wire welding is power source synchronization. If the power sources operate in a constant voltage mode, the flow of total and bypass currents depends on wire feed speed and voltage setting. The major concern in multiple-wire welding is the arc instability due to the electromagnetic intersection between the arcs that can be reduced but cannot be completely eliminated.
