An arc welding method has been. developed in which welding current is switched alternately to each electrodes of TIG and MIG welding methods to prevent the arc interaction between the two electrodes. This method is hereinafter referred as switching TIG-MIG welding method. In this method, the polarity of the tungsten electrode of TIG is negative to eliminate the consumption of the electrode and the polarity of the feeding wire of MIG is positive to increase melting of the feeding wire.
In observing the arc phenomena of this method, authors clarify that stable arcs without any interactions between the two electrodes are maintained by feeding the welding currents switched by transistor curcuits in a frequency of about 200 Hz. Furthermore, the feeding wire is easily melted at the tip and the droplets of the weld metal are periodically removed from the top of the wire without spattering due to exposing the. feeding wire in thee arc of TIG.
In this welding method, since the welding currents of TIG and MIG are able to change independently to each other, the feeding wire of MIG can feed without varing the heat input complementing insufficient welding current to penetrate the base metal by the heat input of TIG.
