Determining the critical transition current for metal transfer in gas metal arc welding (GMAW)

It is of great significance to determine the critical transition current from globular transfer to spray transfer in gas metal arc welding (GMAW) because metal transfer modes affect the weld quality and welding productivity. In this study, a simple model is developed to calculate the critical transition current based on the analysis of various forces exerted on a pendent droplet at the electrode tip. It is found that the force exerted by the incoming molten metal from the wire on the drop, i.e., the term <c v c, plays an important role in determining the critical transition current. For mild steel wires and argon shielding gas, the critical transition current is predicted with different levels of wire diameter and extensions. The calculated results match the experimental ones. © Higher Education Press and Springer-Verlag GmbH 2008.