PURPOSE:To increase the maintaining performance of the molten pool and to improve the working efficiency in all position welding, by supplying the pulse current which is synchronized in phase with the medium frequency DC pulse current of welding current, to the filler wire. CONSTITUTION:The DC welding current which is pulse controlled to several tens to several hundred Hz in frequency, is supplied from pulse power source 7 to electrode 8 of welding torch 3, and the welding arc is generated. Pulse power source 9 is controlled by phase controller 10 simultaneously with the starting of welding, and the pulse current generated from pulse power source 9 is supplied to filler wire 5 after it is controlled in synchronizing phase with the pulse waveform of DC welding current. Then the end of filler wire 5 is inserted into the molten pool as it is melted rapidly by passing it through the high temperature plasma gas flow of welding arc column from the backside of proceeding direction A of torch 3 and thus the welding is proceeded. Moreover, when a bias current is added to current Ib which is supplied to filler wire 5, the molten pool can be maintained more effectively.
展开▼
