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Nd:YAG激光-脉冲MAG复合热源焊熔滴过渡分析

Analysis of droplet behavior in Nd:YAG laser-pulsed MAG hybrid welding

  • 摘要: 采用高速摄像技术拍摄熔滴形成、长大及脱落的过程,观测并分析激光加入对电弧焊熔滴过渡的影响.结果表明,发现激光改变了熔滴的空间飞行轨迹、过渡稳定性、熔滴过渡模式.并从熔滴受力角度建立了脉冲MAG焊接熔滴力学模型,分析了激光加入后熔滴受力状态的改变情况.分析发现复合激光后,脉冲MAG熔滴还受到额外两个力的作用,即激光小孔产生的高速向上喷发的金属蒸气对熔滴过渡的反推力和激光及光致蒸气等离子体对熔滴的热辐射而使被辐射面的液态熔滴金属高速蒸发而产生的反推力,这些反推力在光丝间距小于2 mm,会阻碍熔滴过渡;并且电磁力的方向偏向激光小孔.Nd:YAG激光-脉冲MAG复合热源焊接熔滴过渡稳定性受光丝间距、激光能量、离焦量等参数影响.

     

    Abstract: This paper studies the metal transfer phenomenon of Nd:YAG laser-pulsed MAG hybrid welding. High-speed video camera has been used to record droplet formation, growth and shedding process, observation and analysis for the effect of laser on the droplet transfer of arc welding can be conducted. The results show that the laser changes the droplet flight path, the transition stability and metal transfer mode. A mechanical model established to analysis how laser join influence the force on the droplet in pulsed MAG welding. Analysis showed that when hybrid with laser, the pulse MAG droplet is also subject to additional role of two forces, one is an anti-thrust force produced by the high-speed metal vapor eruption from keyhole acted on the droplet, the other is an anti-thrust force produced by the radiation of laser and laser-induced plasma let the surface of the droplet high-speed evaporation and reverse thrust. When the distance between laser and arc less than 2 mm, these two forces will hinder the droplet, and the electromagnetic force bias direction to laser keyhole. The metal transfer stability Nd:YAG laser-pulsed MAG hybrid welding affected by such as light DLA, laser power and defocus.

     

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