Study Of Activating Fluxes Based On Oxides For Magnesium Alloys

Magnesium alloys with light weight advantages are widely used in automotivemanufacturing industry, both in the field of aerospace, notebook computers, digitalaudiovisual equipment, digital cameras and mobile phones and other fields have a verybroad application prospects. Activating flux TIG welding process is simple and low costs,high efficiency, good weld formation. So chose activating flux TIG welding to studymagnesium alloys has great significance. But currently study most focus on singleactivating flux, there is little systematic research on formula of activating fluxes, so thispaper systematiclly research on formula so that get optimal formula.In this paper, three common oxides were chosen (titanium oxide, chromium oxide andcalcium oxide). Single activating flux, binary activating agen and ternary activating fluxeswere coated on the surface of the magnesium alloys, respectively, and then the magnesiumalloys were welded by TIG. After welding, optical microscopy、scanning electronmicroscopy、vickers hardness tester and X-ray diffraction were used to examine the weldshape and the effect of activating fluxes on weld penetration and width、microstructure andproperties under different conditions, and then selected the optimal mixed activating fluxcomponents. In order to further improve weld formation and performance, an externalmagnetic field was added based on the optimal mixed activating flux components, and themechanism of activating fluxes to increase weld penetration was also studied.Experimental results show that: The introduction of activating fluxes can increaseweld penetration, in all of the activating fluxes formulation, titanium oxide increase weldpenetration best; in binary of activating fluxes, the best to increase the weld penetration isformulation which contain50%titanium oxide and20%chromium oxide; when thecontent of titanium oxide, chromium oxide and calcium oxide is50%、25%and20%respectively in ternary activating flux, the weld penetration reaches a maximum, the shapefactor reaches a minimum. The introduction of activating fluxes can increase the hardnessof weld joint, but have no influence on microstructure. After the introduction of an externalmagnetic field, when the magnetic frequency is10Hz and the magnetic current is2A, the effect to increase weld penetration is the most obvious, the weld penetration is5mm, that isthe depth of basic metal, and under this parameter, the hardness of weld joint reach amaximum of100.1HV, and the weld grain size are obviously refined.