Gas transfer flux activating TIG welding process for aluminum alloy

A new activating TIG welding process, gas transfer flux activating TIG (GTFA-TIG) welding, is proposed for welding aluminum alloy by changing the introduction method of active elements. In this process, a flux is transferred to shielding gas through an automatic powder feeder, and the shielding gas carries the active elements into the welding arc and weld pool. In this way, the welding arc is contracted, and the flow pattern in the weld pool is changed, finally, the weld depth increases. Without coating the flux, the automation of welding process is realized. Compared to the conventional AC TIG welding, the effects of fluxes on the weld shape, tensile property and defects of GTFA-TIG welding with eight kinds of single-component fluxes were investigated. It proves that most of halide and oxide fluxes can improve the weld depth up to 2.5-3.0 times of that of traditional TIG welding, while the effect of Te flux is less effective. The tensile strength of the joint with V2O5 flux is close to that of base metal, but it is lower than that of base metal when using MnCl2 and AlF3 fluxes. The X-ray detection of defects shows that the welds with V2O5, MnCl2 and AlF3 fluxes are assessed as grade I, while that with Te flux is grade III.