Effect of Nature of Flux and Flux Gap on the Depth-to-Width Ratio in Flux-Bounded TIG Welding of AA6061: Experiments and Numerical Simulations

Flux-bounded tungsten inert gas welding is a variant of activated tungsten inert gas welding wherein activating flux is applied on the weld surface with a narrow flux gap along the line of weld. In this study, bead-on-plate welds were performed with flux gaps of 2, 3, 4, 5 and 6 mm using the fluxes silicon dioxide, titanium dioxide and calcium fluoride. The weld bead profiles were obtained using a stereomicroscope from which the depth-to-width ratios (DWRs) were calculated and compared with the DWR of a tungsten-inert-gas-welded plate. The reasons for differences in DWR were explained using the mechanisms involved and the captured images of the welding arc profile. The microstructure of the weld beads revealed no entrapment of flux particles. The increase in the DWR in the presence of activating flux was also substantiated using a numerical simulation model.