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针对铝合金电阻点焊的工艺不稳定性和低电极寿命问题,分别采用多环圆顶电极(MRD)和平头电极对2 mm厚5182-O铝合金进行电阻点焊对比试验。通过对焊点进行拉剪与正拉强度稳定性测试,对焊点、电极表面形貌进行对比研究。结果表明:相对于平头电极,MRD由于圆环的存在使氧化膜在电极压力的作用下被挤压到圆环附近,从而使氧化膜规律性分布,通过环形触点在合金内部形成导电,电流均匀通过,提高产热效率;而且增大材料与电极间的接触面积使产热减小,提高电极寿命。因此,MRD可有效克服铝合金表面氧化膜带来的问题从而提高工艺稳定性。
Aiming at the problem of process instability and low electrode life of aluminum alloy resistance spot welding, resistance spot welding comparison experiments were carried out on 2 mm thick 5182-O aluminum alloy using multi-ring dome electrode (MRD) and flat-head electrode respectively. Through the welding point of the tensile shear and the stability of the tensile test, the welding spot, the electrode surface morphology were compared. The results show that compared with the flat electrodes, the MRD is pressed into the vicinity of the ring by the pressure of the electrode due to the presence of the ring, so that the oxide film is regularly distributed and the conductive and current flows through the ring-shaped contact within the alloy Even through to improve the thermal efficiency; but also increase the contact area between the material and the electrode to reduce heat production, improve electrode life. Therefore, MRD can effectively overcome the problems caused by the oxide film on the surface of the aluminum alloy to improve the process stability.