2016 Volume 34 Issue 4 Pages 223-230
GMA welding under pure argon shielding gas atmosphere (pure argon-GMA welding) is suitable to obtain a high-strength and high toughness welded joint. However, it is difficult to apply pure argon-GMA welding practically to welding structure because of arc instability. In order to perform stable pure argon-GMA welding, duplex current feeding GMA welding has been developed. The duplex current feeding GMA welding consists of primary GMA welding current by constant-voltage power source and secondary current by constant-current power resource. In previous experimental study, it was found that the temperature of a droplet by duplex current feeding GMA welding was higher than the conventional GMA welding. In this study, mechanism and basic characteristics of duplex current feeding GMA welding are investigated by numerical simulation with a simplified duplex current feeding GMA welding model. As a result, it was found that total welding current was largely increased by conducting the secondary current in addition to the primary GMA welding current under the same arc voltage and wire feed speed. Furthermore, the droplet temperature was also increased due to the increase in total welding current.