1995 Volume 13 Issue 1 Pages 54-64
The investigation results on the resistance spot weld quality of Al-Mg alloy sheet are summarized as follows;
(1) Comparison of continuous spot weldability with mild steel sheet Compared with mild steel, the Al-Mg alloy exhibits degradation and variation of tensile shear strength associated with continuous resistance spot welding, and causes excessively serious wear in electrodes.
(2) A study for variation of tensile shear strength in continuous resistance spot welding Variation of tensile shear strength in continuous resistace spot welding is due to nonuniform corona bond formation and nonuniform nugget size and profile.
(3) Effects of oxide film and heat condition, (1) The oxide film causes localized wear in electrodes, and in addition, even prevents the formation of corona bond. (2) If the heat input after saturation of nugget growth is regaded as extra heat, it promotes wear in electrodes and causes corona bond formation. (3) Variation of tensile shear strength is improved mainly by removing oxide film. In addition by reducing the heat input, it causes degradation of tensile shear strength and makes the failure mode sparse, the formation of corona bond is suppressed and then tensile shear strength become stable and electrode life is extended.
