The Effects Of Oxide Activating Fluxes On TIG Welding Of AZ31B Magnesium Alloy

In the paper, magnesium alloy AZ31B is selected with the simple operation and low cost as welding method, which use TiO₂ and Nd₂O₃ as the main active agent. The amount of active agent effected on the macro-morphologies, microstructures, mechanical properties and corrosion wear resistance are systematically studied with different coatings. The relationship of microstructure, mechanical properties and corrosion resistance are revealed. This paper also provides some theoretical basis and practical experience for the study.The aspect ratio of the weldings can reach to maximum when the amount of TiO₂ and Nd₂O₃ are 5.40mg/cm2 and 2.45mg/cm2 under these parameters. The aspect ratio of the weldings are 0.50 and 0.53 respectively with good welding morphology. The macrohardness with Nd₂O₃ is better than TiO₂. Tensile fracture of welded joints are in the position of the weld fusion zone whether or not coated with active agent. When the amount of active agent increases, the fracture mode changes from cleavage to the quasi-cleavage. Nd₂O₃ can improve corrosion resistance of welding joints, the average corrosion rate reduces from 1.15g/?m2·h? to 0.8g/?m2·h?, but TiO₂ doesn't work on it. Comparing with the effects of TiO₂ to magnesium alloy, has seen a better value.