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In this paper,resistance spot welding were performed on 1mm-thickness magnesium AZ31B plates.The effect of welding current on the microstructure and tensile shear force was investigated.It was found that the welding current governed the nugget growth,and the nugget could not form if current levels were insufficient.The nugget revealed a homogeneous,equiaxed,fine-grained structure,which consisted of non-equilibrium microstructure of α-phase dendrites surrounded by eutectic mixtures of α and β(Mg17Al12) in the grain boundaries.With increasing welding current,the size of grains in nugget would be more smaller and uniform,and the width of plastic rings would be larger.Tensile shear tests showed that tensile shear force of the joints increased with increasing welding current when the welding current was smaller than 17 000 A.The maximum tensile shear force was up to 1 980 N.
In this paper, resistance spot welding were performed on 1mm-thickness magnesium AZ31B plates. The effect of welding current on the microstructure and tensile shear force was investigated. It was found that the welding current governed the nugget growth, and the nugget could not form if current levels were insufficient. nugget revealed a homogeneous, equiaxed, fine-grained structure, which consisted of non-equilibrium microstructure of α-phase dendrites surrounded by eutectic mixtures of α and β (Mg17Al12) in the grain boundaries. current, the size of grains in nugget would be more smaller and uniform, and the width of plastic rings would be larger. Sensile shear tests showed that tensile shear force of the joints increased with increasing welding current when the welding current was smaller than 17 000 A.The maximum tensile shear force was up to 1 980 N.