Plasma Welding of Aluminum Alloys with the Use of Two Direct ARCS on Reverse-Polarity Current

The use of plasma-based technologies elevates productivity and product quality in the fabrication of welded structures made of aluminum and its alloys. High-power heat sources must be used to achieve high levels of productivity in the welding of aluminum structures. Also, the presence of an oxide fi lm that impedes the formation of the weld dictates the use of reverse-polarity current in the arc welding of such structures. The use of combination heat sources can resolve the problem of improving quality and productivity in the welding of aluminum alloys. This article presents results from a study of the plasma welding of aluminum alloys with the use of a dual-arc plasmotron that provides for the combustion of two direct arcs on reversepolarity current. It is shown that the plasmotron can operate stably under these conditions. Use of the given technology reduces the thermal load on the plasmotron, enhances its ability to melt through the alloys, improves cathodic cleaning of the metal's surface in the region of the weld, and ensures the formation of welds that are free of defects.