Study On The Activating Flux Coated Wire For Magnesium Alloy

For the characteristics of low density, high specific strength, good electromagnetic shielding and recyclable, Mg alloys are used in many fields, such as aerospace vehicle, automobile, consumer electronic productions. However, the filler wire of Mg and its alloy can't meet the demands of manufacturing at present and it has been the main problem which limits the application of magnesium alloy structural components. Hereby, the research on Mg filler wire is becoming a focal topic all over the world. In this paper, manufacture of the normal filler wire and flux coated filler wire, the effect of the flux coated wire on weld penetration, the complex formula of the fluxes were studied and the mechanism of weld penetration increase was discussed.The results showed that magnesium alloy welding wire can't be fabricated by drawing method as aluminum alloy wire for its poor plasticity, which results in magnesium alloy's close-packed hexagonal lattice and few slip system. In this study, hot-extruding process has been adopted with proper process parameters, and magnesium alloy welding wire has been fabricated successfully.Flux coated wire was prepared by coated the flux on the surface of the normal filler wire. The weld penetration was increased by the use of the flux coated wire, and the maximum increase level is the 300% of the weld penetration using normal wire. The boiling points of the fluxes that increased weld penetration most are mostly in the regions about 900℃. In flux coated wire weld, the welding arc constriction is generated by the dissociation of the constituent elements of the flux. The constricted welding arc leads to a increasing in arc voltage, current density and arc temperature.The interfusion ability between the droplet metal and the welding pool metal became worse in the single flux coated wire weld than the normal wire, and that indicated filling ability of the filler wire became bad. The complex formula which is composed of oxide fluxes is designed with the uniform design. The use of the complex formula flux can not only increase the weld penetration but also improve the filling ability of the flux coated wire.