Study on metal transfer behaviour in metal inert gas arc welding with activating flux for magnesium alloy

The investigation on the influences of the KCl, TiO₂ and CaCl₂ fluxes on the metal transfer and the spatter loss in metal inert gas (MIG) welding of magnesium alloy is carried out. The results indicate that KCl flux favours the stability of metal transfer and reduces the spatter loss, whereas the extension of the period of metal transfer and the aggravation of the spatter loss are produced by CaCl₂ flux, compared with MIG welding. For TiO₂ flux, the metal transfer behaviour and the spatter loss are similar to those of MIG welding. The reason for promoting the metal transfer on KCl flux is that the increased electromagnetic force resulted from the enhancement of the welding current. In addition, for MIG welding with the KCl or CaCl₂ flux, the arc conductivity is affected together by the metallic atoms and the chlorine atoms contained in the two fluxes.