WELDING METHOD BY COMBINATION OF COMPRESSED AND FREE ARCS Russian patent published in 2022 - IPC B23K9/95 B23K9/16 

FIELD: metallurgy.

SUBSTANCE: invention can be used for welding metals with a combination of compressed and free arcs. A compressed arc of direct action of direct polarity is ignited using a duty arc between a tungsten electrode and a nozzle from a high-frequency arc exciter. Then the duty arc is ignited in case of accidental breakage of the working arc. A refractory insert made of a non-melting electrode is fixed at the end of the plasma torch nozzle. Between this insert and the product, a free arc is ignited, powered from a source of multipolar current pulses with a frequency of at least 50 Hz. The ratio of the average over the period of the current of the pulses of direct polarity in a free arc to the total average current of this arc is chosen in the range of 0.5-0.9. The close location of the compressed and free arcs provides the effect of tandem welding, leading to an increase in the penetration ability compared with single-arc welding. When welding aluminum alloys, the free arc is located in front of the welding direction and cleans the surface from the aluminum oxide film. When welding high-alloy steels, each of the arcs can be placed first.

EFFECT: ignition of compressed and free arcs is performed in any sequence, depending on the technological requirements of the process.

4 cl, 5 dwg, 2 tbl, 2 ex