Stability of droplets in gas metal arc welding

A method is developed to compute the stability of droplets detaching from the consumable electrode in gas metal arc welding. An aluminium electrode is used as the model system. Theoretical predictions and supporting experiments are used to ascertain the rate of transfer of droplets for a range of current encompassing globular and spray transfer, and to examine the transition between these distinct modes of metal transfer. The method uses dimensional analysis to correlate the mass, rate of transfer, and force acting to detach droplets. The correlation is found to undergo a notable change in slope at the transition between globular and spray transfer. The accuracy of the correlation is assessed by comparing the theoretical and measured rate of transfer of droplets in gas metal arc welding using aluminium electrodes of variable diameter.