Physical properties of the plasma-MIG welding arc

Describes measurements of the temperature distribution and the composition of the plasma-MIG arc system using optical spectroscopy. It is found that the central part of the arc contains the elements Fe, Mn, Cu, Ca and Ar at a temperature of about 7000K. The outer regions of the arc show only argon spectral lines and have much higher temperature value ( approximately=13000K). From these measurements a number of conclusions can be drawn about the physical properties of the plasma-MIG welding arc. The most important conclusion is that only a very small part of the wire current flows through the bright inner arc.