Welding of magnesium alloys with activating flux

Abstract

The effects of an activating flux on AZ31B alloy welding were investigated. Alternating current tungsten inert gas (ACTIG) welding was used to weld 5·0 mm thick AZ31B alloy plates with CdCl₂, AlF₃ and TiO₂ activating flux. Applying the activating flux on the AZ31B alloy surface led to an increase in weld penetration depth. Various welding conditions, such as welding current, welding arc length, welding shielding gas flowrate, welding speed and flux thickness, influenced to different extents the ability of the activating flux to increase weld penetration. Furthermore, a high speed camera was used to monitor the arc images during welding. It was found that the brightest region of the arc was broader when CdCl₂ and AlF₃ were used, while the stability of the arc was increased when TiO₂ was used, especially in the positive electrode period. In summary, it is important that a uniform flux layer is present at the alloy plate surface and suitable welding parameters are selected.