中国激光, 2007, 34 (s1): 259, 网络出版: 2009-05-25
激光-MIG复合热源焊接熔滴过渡力学行为分析
Study on Droplet Transfer Mechanical Behavior in Laser-MIG Hybrid Welding Process
光学设计与制造 激光-MIG复合焊接 熔滴过渡 受力机制 数值分析 optical design and fabrication laser-MIG hybrid welding droplet transfer force mechanism numerical analysis
摘要
针对激光等离子体和电弧等离子体共同作用下的熔滴过渡,根据气体动力学和静态力学平衡理论,对CO2激光-惰性气体金属弧焊(MIG)复合焊接过程中熔滴的复杂受力状态及其力源的产生与作用原理进行了深入分析。结果表明,一方面由于激光焊接过程中材料剧烈气化时产生的大量金属蒸气射流,对熔滴形成了巨大的反冲作用力,阻碍了熔滴过渡;另一方面,由于激光焊接产生的等离子体改变了原有惰性气体金属弧焊电弧等离子体形成路径,从而改变了原有焊接熔滴中的电流密度分布和流向而形成了一个新的复合电弧收缩力。两者综合作用降低了复合焊接熔滴过渡频率,破坏了焊接稳定性。在此基础上,进一步研究了焊接参数对金属蒸气反作用力、复合电弧收缩力等的影响规律,并采用数值分析的方法推导出了它们的数学描述;定量分析了复合热源作用下熔滴的受力机制,揭示了复合热源焊接过程中熔滴受力状态与焊接稳定性之间的内在关系。
Abstract
Aiming at the droplet transfer behavior under actions of laser plasma and arc plasma together, the origin and action principle produced the force on droplet are profoundly analyzed according to the theory of gas dynamics and the static force balance. The experimental results indicate that the rejecting force caused by metal vapour prevents the droplet from detaching when the material evaporates at the high power density of laser. On the other hand, the laser plasma from laser-induced keyhole changes the original path of MIG arc plasma, which results in that the current density distribution and flow of conventional MIG arc are varied, and produces a new hybrid electromagnetic force in the CO2 laser-MIG hybrid welding process. As a result, the droplet transfer frequency is decreased, and the welding process becomes unstable. Furthermore, the influence of welding parameters on vaporization-induced recoil force and the hybrid electromagnetic force caused by laser plasma and arc plasma together are also studied, and the mathematical descriptions is deduced by adopting numerical analysis, which consequently analyzes the force mechanism of droplet quantitatively, and discloses the internal relationship between the force state of droplet and welding stability in CO2 laser-MIG hybrid welding process.
雷正龙, 李俐群, 陈彦宾. 激光-MIG复合热源焊接熔滴过渡力学行为分析[J]. 中国激光, 2007, 34(s1): 259. 雷正龙, 李俐群, 陈彦宾. Study on Droplet Transfer Mechanical Behavior in Laser-MIG Hybrid Welding Process[J]. Chinese Journal of Lasers, 2007, 34(s1): 259.