Study On The Arc Behavior In The YAG Laser+Double-wire MIG Hybrid Welding With Single Power

Laser-Arc Hybrid Welding was proposed by W. Steen from the British ImperialUniversity in the late1970s. Currently, hybrid welding researches are mainly focusedon the applications of welding process and simulation of laser+single arc hybridwelding, but on laser+twin-arc hybrid welding is rarely researched. When two wireswere connected on the single power, in parallel, the unique phenomena of alternatearcing will happen. Tests show that the alternate arcing frequency is the key factorthat affects the stability of this welding process.In this study, a single power twin-MIG arc welding system and a YAG laser+single power twin-MIG arc hybrid welding system have been established. Electricsignals and synchronous high-speed camera signals are applied to explain two kindsof alternate arcing in the pulse mode and the unusual alternate arcing in thedirect-current mode based on the twin arc welding tests without laser and to analyzethe effect of each welding parameters on the alternate arcing frequency. Comparingthe YAG laser+single power twin-MIG arc hybrid welding system and the singlepower twin-MIG arc welding system, analyze the effect of the laser on the alternatearcing frequency through the change of arc behavior and droplet transfer because oflaser.Under certain conditions, there are two forms of alternate arcing in pulse mode,the one with the short circuit and the one with no short circuit; under certainconditions, the above-mentioned two forms of alternative arcing can happen in onewelding process in the DC mode. With two-wire distance decreasing, the alternatearcing frequency increases; with arc voltage decreasing, the alternate arcing frequencyincreases; when wire feed speed increases, the alternate arcing frequency increases;With welding speed gradually increasing from3mm/s to10mm/s, the alternatearcing frequency decreases firstly and then increases, it reaches the minimum whenthe welding speed is6mm/s; when torch angle increases, the alternate arcingfrequency decreases; under the same welding parameters, when the direction of twowires are parallel to the welding direction, the alternate arcing frequency is larger thanthe one when the direction of two wires are vertical to the welding directionComparing the YAG laser+single power twin-MIG arc hybrid welding systemand the single power twin-MIG arc welding system, at the alternating moment whendouble-wire distance is7mm, the arc is attracted to the laser, the pinning and recoileffect of the laser to the arc exists simultaneously, the droplet transition frequencydecreases, the droplet size increases and the alternate arcing frequency increases. At the alternating moment when double-wire distance is15mm, the arc is attracted to thelaser, the pinning effect of the laser to the arc is obvious, while the recoil effect almostdisappears, the welding process presents periodical. The droplet transition frequencydecreases, the droplet size increases and the alternate arcing frequency decreases. Atthe alternating moment when double-wire distance is3mm, the arc is attracted to thelaser, the recoil effect of the laser to the arc is obvious and the welding processbecomes more stable. The droplet transition frequency increases while the droplet sizeincreases.