Grain refinement and improved properties through electromagnetic stirring in AI alloy MIG welds

This paper described the effects of external excitatory parameters of current and frequency on the microstructure and mechanical properties of weld metal in M1G welding with longitudinal electromagnetic field. With a high speed video camera capturing the images of arc shape, the mechanism of arc rotation and how the periodic contraction and expansion of arc affected the movement of molten pool were investigated. The technique resulted in fine equiaxed grains in weld metal and optimum parameters of electromagnetic stirring were suggested based on the extent of refinement. Fine-grained weld metal exhibited better yield strength and significant improvement in elongation.