Investigation on welding arc interruptions in the presence of magnetic fields: Arc length, torch angle and current pulsing frequency influence

摘要

Arc interruptions have been observed in tandem pulsed gas metal arc welding (GMAW). This fact, which is likely related to magnetic interaction between the arcs, motivated previous study concerning the influence of the welding current on this phenomenon. In order to promote further understanding, this paper investigates the effects of arc length, torch angle, and high-frequency current pulsing on the arc resistance to extinction. To mimic the situation found in tandem GMAW (magnetic field induced by one arc acting on the other arc), external magnetic fields were applied to gas tungsten arc welding arcs. It was verified that short arc lengths and torch angles set to push the weld pool increase the arc resistance to extinction, whereas the utilization of high-frequency current pulsing tends to weaken the arc resistance to extinction. According to a model devised from the results, the arc extinction takes place if the heat generated inside and the heat transferred into the arc column become insufficient to counterbalance the total heat loss in this arc region.