激光扫描焊接熔池及等离子体动态行为

以5A06铝合金为试验材料，采用高速摄影技术对激光扫描焊接过程中的熔池及等离子体羽辉动态行为进行拍摄，对比分析了常规单激光焊接与激光扫描焊接条件下的熔池表面流动特征和等离子体羽辉波动特征. 结果表明，一定条件下的摆动激光光束相比于单激光光束，能够极大地增强等离子体羽辉的稳定性，延长其存在周期，同时熔池流动的方向性增强，稳定性提高，整个焊接液态熔池表面不存在“回流”现象，熔池流动产生的流体动压力对匙孔的冲击力作用降低，匙孔的稳定性提高.

Dynamic behavior of laser scanning welding pool and plasma

With the material of aluminum alloy 5A06, the weld pool and plasma plume dynamic behavior during laser scanning welding were photographed by using high-speed photography. The character of fluidity for molten pool surface and of plasma plume vibration were analyzed under conventional single laser beam and laser scanning welding.The research results showed that compared with Single laser beam, the oscillating laser beam can greatly enhance the stability of plasma, prolong the cycle, increase the direction of the molten pool flow at the same time, and improve the stability. On the whole welding molten pool surface backflow phenomenon did not occur. Dynamic pressure resulting from molten pool flow reduced the impact of the keyhole. The keyhole stability is greatly improved.