旋转电弧焊接熔池温度场与流场数值模拟

Numerical Simulation of Temperature and Flow Fields of Weld Pool during Rotary Arc Welding

建立了旋转电弧焊接热源模型,综合考虑了电磁力、熔滴冲击力、表面张力、电弧压力、浮力等外界作用,对旋转电弧焊接条件下的熔池温度场和流场进行了数值模拟。模拟结果表明,电弧不旋转焊接时,在熔池的上部,铁水由熔池中心向熔池边缘流动,流场和温度场在焊缝的横截面上均呈现出对称分布的特征;在熔池的下部,铁水由熔池边缘向熔池中心流动,这种流动导致了指状熔深的产生。旋转电弧焊接时,在熔池中产生了一个绕着电极轴线逆时针运动的涡状流动,熔池的流场和温度场在焊缝的横截面上不再对称;在熔池的下部,则没有出现铁水由熔池边缘向熔池中心流动的情况,与普通焊接相比,熔池的熔宽变大,熔深变小。

A heat source model of rotary arc welding was established, the temperature and flow fields of weld pool during rotate arc welding process were simulated. The influence of electromagnetic force, droplet impact force, surface tension, arc pressure and buoyancy was considered. The simulation results show that during the welding without arc rotation, the molten iron flows from the weld pool center to the weld pool edge in the upper part of molten pool, and the flow field and the temperature field show symmetrical distribution in the weld cross section. In the lower part of molten pool, the molten iron flows from the edge to the center of the pool, which leads to generation of finger penetration. During rotary arc welding, a vortex flow around the axis of the electrode is formed against clockwise in the molten pool, the flow field and the temperature field of the molten pool are no longer symmetrical in the weld cross section. In the lower part of weld pool, there is no molten iron flow from the edge to the center of weld pool. Compare to that of traditional welding, the weld width of molten pool becomes bigger and the penetration becomes smaller during rotating arc welding process.