METAL VAPOUR IN ATMOSPHERIC-PRESSURE ARCS

摘要

Metal vapour plays an important role in many applications of atmospheric-pressure arcs, including arc welding and circuit interruption. For example, in gas-metal arc welding, metal vapour is formed mainly by evaporation of the wire electrode, and its concentration can reach over 50%. The presence of vapour strongly affects the arc temperature and the weld penetration. In low-voltage circuit breakers, metal vapour is formed by evaporation of the electrodes (runners) and the splitter plates, and can have a major influence on the motion of the arc, in particular as it enters the splitter plates. Experimental and modelling results on the influence of metal vapour in gas-tungsten arc welding, gas-metal arc welding and low-voltage circuit breakers will be presented. The effects of the metal vapour will be explained in terms of its influence on the transport and radiative properties of the plasma.