电阻点焊温度场分布的数值模拟

为研究点焊时焊接规范对电极温度的影响，以及镀锌钢板点焊时焊接参数的选择，利用轴对称有限元程序模拟了电阻点焊的过程中电极与工件的温度场分布，模型中采用标定法来解决接触电阻产热的问题；运用生死单元技术解决镀锌钢板焊接时镀锌层熔化的模拟问题。结果表明，有限元点焊模型可以得到与实际焊接十分吻合的模拟结果。电阻点焊时，不同规范的焊接参数对电极的温度分布影响较大，采用标准规范时电极的温度最低，故选择焊接规范时应考虑到对电极的影响。镀锌钢板焊接时，熔化的锌层对焊接过程以及电极温度分布有显著影响，若采用无锌钢板的焊接规范基本上不能形成熔核，而政党焊接时电极最高温度将比无锌钢板点焊时高出20%，因此，加何降低电极温度是一个重要问题。

Numerical Simulation on the Temperature Distribution in Spot Welding

An axisymmetric finite element program was developed to simulate the process of resistance spot welding. The effect of welding condition on the temperature distribution in the electrode and the determination of welding conditions on galvanized steel sheet were studied. A calibration method was used to deal with the contact resistance in welding. A method of active and deactive element was also employed to simulate the effect of molten zinc on galvanized steel sheet on the welding process. The results show that the model can simulate the spot welding process very well. The welding conditions have a significant effect on the temperature distribution of the electrode. The lowest temperature of electrode can be reached when using standard welding condition. The molten zinc on galvanized sheet during welding can give influence on the temperature distribution of the electrode in a great deal. It is very important to consider the cooling of the electrode when welding a galvanized sheet.