Droplet transfer and spatter generation in DC-AC pulse tandem gas metal arc welding

Tandem welding increases productivity in gas metal arc welding (GMAW). We investigate asynchronous DC-AC pulse tandem GMAW. We analyse welding arc and droplet behaviour for two tandem welding processes, DC standard-AC pulse and DC pulse-AC pulse. Spatters were generated by attractive and repulsive arc interferences. The attractive arc interaction hinders stable droplet transfer and the repulsive one can induce short-circuiting of the hanging droplets. We examine the effect of process parameters on droplet transfer and spatter generation. During DC pulse-AC pulse tandem GMAW, high peak current of the DC pulse increases arc stiffness and enhances droplet detachment. The observed consistency in arc length, droplet formation, and droplet transfer confirms the stability of asynchronous DC pulse-AC pulse tandem GMAW.