| 摘要 |
PURPOSE:To expand the range of adaptation by changing the waveforms of pulse currents to be superposed on base current thereby improving the stability of the arc in a small current region and decreasing an average welding current value of a lower limit. CONSTITUTION:The 1st pulse trains P1, P3 having a uniform period T are generated, and the 2nd pulse trains P2, P4 are generated with delay of a certain time (t) (t<T/2). The reference pulse trains P1, P3 and the delay pulse trains P2, P4 are superposed on base current IB. With the superposed currents as welding current, arc welding is executed. Then, for example, when a droplet is transferred to base materials at the reference pulse P1, the delay pulse P2 preheats a welding wire, and assists the transfer of droplets at the pulse P3 right thereafter. If the droplet fails to transfer at the pulse P1, the droplet can be transferred at the pulse P2 right thereafter. As a result, the excessive growth of the droplet is prevented, and the sure transfer of the droplet with lower current is made possible. |
