5052铝合金电阻点焊电极形状对电极寿命的影响

Influence of the Electrode Shape on Service Life in 5052 Aluminum Alloy Resistance Spot Welding

利用ANSYS软件建立了直径分别为6和8 mm的锥台电极和直径16 mm的球电极所对应的5052铝合金电阻点焊过程的有限元模型,分析了在相同的焊接工艺参数下3种类型电极几何形状对5052铝合金电阻点焊的熔核形成过程及其焊接质量和电极自身磨损的影响,并通过连续点焊试验验证了模型的准确性.结果表明:对于锥台电极,在相同的焊接电流条件下,电极端面直径越小,所得到的熔核尺寸越大,点焊接头质量越好;球电极与工件的接触面积过小,将会使得电流集中、温度过高而发生严重的电极烧损.所建模型的模拟结果与试验结果的误差在4%以内,采用直径6 mm的锥台电极进行5052铝合金薄板焊接时,电极寿命比球电极提高了20%.

Numerical simulations of resistance spot welding with different electrode(Ф6 mm, Ф8 mm cone electrodes, and Ф16 mm ball electrode) were performed by ANSYS to examine the effect of the nugget shape on the weld properties and the service life of the electrodes under the same parameters. Continuous spot welding is carried to verify the correctness of the finite model. The results indicate that as for the cone electrode, the smaller the diameter of the electrode is, the larger the size of the nugget, and the weld joint has good performance. The contact area between the ball electrode and the work piece is too small and the joule heat generated is large. So, the ignition loss of electrodes is a crucial problem for the ball electrode. The simulation results are in good agreement with the metallographic results. The service life is improved by 20% compared with the ball electrode when the 5052 thin plate is welded by Ф6 mm cone electrode, which provides the theoretical basis for selecting the electrode shape.