The rate of melting of the electrode during arc welding. The influence of discrete removal of the melt

Molten droplets a.re removed periodically from the electrode's tip during are welding. During the process the thickness of the molten layer that separates the heat source (plasma) from the solid wire to be melted also changes periodically. Correspondingly, the instantaneous rate of melting experiences periodic variations. It is shown that the periodicity of removal of the melt affects the average rate of melting. The effect is small for small Peclet numbers (Pe = vL/alpha, where v is the rate of melting, L is the size of the detaching droplets and Lu is the thermal diffusivity), but it is very pronounced for high Peclet numbers. Comparison of the calculated rate of melting with the rate measured during are welding shows that good agreement has been obtained taking convection of the melt into account.