铝合金激光-MIG复合焊熔滴对匙孔作用的模拟

将复合焊接过程中的反冲压力、表面张力等驱动力及熔滴过渡行为考虑在内，建立5A06铝合金激光-MIG复合焊接数值模拟热流耦合模型，由于熔池内的流动及匙孔稳定性对焊接性能有重要影响，因此针对熔滴与匙孔及熔池稳定性的影响进行了系统讨论，并且通过采用不同的熔滴落入位置进行计算.结果表明，当熔滴落入位置距激光中心较近时，熔滴对匙孔的冲击作用较大，匙孔壁的平均流速和波动频率有所增加，匙孔更易由于周期性的熔滴过渡而产生液桥发生闭合，熔滴落入位置还会影响匙孔深宽比，进而影响激光能量的菲涅尔吸收.

Simulation analysis of droplet action on keyhole during laser-MIG composite welding of aluminum alloy

In this paper, a coupled thermal flow model for 5A06 aluminum alloy laser-MIG hybrid welding is developed, which takes account of the driving forces such as recoil pressure, surface tension and droplet transfer behavior. The flow in the molten pool and the stability of the keyhole have an important impact on the welding performance, therefore, the influence of droplet and keyhole on the stability of molten pool is discussed systematically through numerical simulation with different droplet location. It is found that the impact of the melt drop on the keyhole is greater, the average velocity and wave frequency of the keyhole wall increase, and the keyhole bridge is more likely to be closed due to the periodic droplet transition, when the melting drop is close to the laser center. In addition, the location of melting drop will also affect the ratio of depth to width of the keyhole and thus affect the Fresnel absorption of laser energy.