CO₂ arc welding is widely accepted since a high current density in the process assures a high reliability in the welding and CO₂ gas is cheap in comparison to Ar and other shielding gases. But it has a drawback in the spattering that is brought about by short-circuiting of welding wire and base metal. This paper is aimed to determine an optimum current waveform that suppresses the spattering. With the optimization, the droplet produced at the tip of the welding wire is transfered from the wire toward the base metal without short-circuiting. The way a droplet is transfered has been investigated with various kinds of pulse current waveforms by taking high-speed framing pictures.
The results are as follows:
(1) The repetitive application of double pulse current is suitable to transfer the droplet regularly without short-circuiting. With the pulse current, the droplet falls off before it grow too large.
(2) The droplet transfer is reproducible in every cycle of the double pulse current as far as the voltage across the arc is maintained constant at the starting-point of the pulse.