The optimal welding parameter combination was determined in
the previous experiment using the Taguchi method, and the effect
of each parameter was determined by ANOVA and contribution
analysis, then experiments with activating flux GMAW were carried
out using these optimal parameters. Three activating fluxes,
i.e. Fe2O3, SiO2, and MgCO3 in powder form, were used. Single-component
flux powder was uniformly dispersed with acetone to produce
paint-like consistency and brush coating was applied on the
plate surfaces as shown in Fig. 2. Then a butt joint was welded with
a single-pass, welding a square groove on carbon steel. After welding,
experiments were also carried out to measure the welding distortion
in the butt-welded joint. Fig. 3 is a schematic diagram of
the welding distortion. The dial indicator moved a distance of DX
along the x-axis, and then a vertical displacement DZ was obtained.
Finally, the angular distortion value h was calculated from the
equation.