大电阻介质下的铝合金电阻点焊

在介绍大电阻介质材料的制备及其在铝合金点焊中的应用方法的基础上,以LF21防锈铝合金点焊为例,经金相试样分析及扫描电镜分析,对比研究了在不同的焊接电流下,应用介质材料与未应用介质材料时的熔核形貌、缺陷及组织.结果表明,未加入大电阻介质的点焊熔核均出现气孔和未熔合缺陷;而加入大电阻介质,形核效果良好,有个别小气孔但未出现影响焊点力学性能的未熔合缺陷.此外,加入大电阻介质降低了对焊件表面质量的要求,从而提高了铝合金点焊质量的稳定性;可降低焊接电流,导致较低的电极温度从而提高了电极寿命.

Resistance spot welding of aluminum alloy with great resistance medium

Based on the introduction of the preparation method of great resistance medium and its application in resistance spot welding of aluminum alloy,the shape,defect and microstructure of nugget of aluminum alloy LF21 both with medium and without medium were studied by metallographic analysis and SEM.The results show that all of the nuggets without medium appear blowholes and lack of fusion,while those with medium appear well.There are only few small blowholes,but no lack of fusion which does more damage to mechanical property of the nugget in the latter situation.Furthermore,the requirement on the surface of aluminum alloy weldment is reduced,which avoids the treatment of weldment surface.The quality of aluminum alloy nugget can be guaranteed easily.The welding current can be reduced,which produces lower electrode temperature and enhances the electrode life.