CO_2激光-MIG复合焊接射滴过渡的熔滴特性

Characteristics of droplet transfer in CO_2 laser-MIG hybrid welding with projected mode

本文以 5 .0mm厚LF6防锈铝合金板为试验材料 ,进行了CO2 激光 -MIG电弧射滴过渡的旁轴复合焊接试验。试验结果表明 ,在激光锁孔效应下 ,CO2 激光 -MIG复合焊接铝合金不仅具有在较宽的参数范围内焊缝成形美观 ,熔深熔宽增加 ,无气孔等优点 ;而且还发现 ,与单MIG焊接的熔滴过渡特性相比 ,复合焊接过程中一方面由于激光能量和激光锁孔效应产生的大量金属等离子体对熔滴的热辐射作用 ,促进了熔滴过渡 ;另一方面由于激光等离子体对熔滴的吸引力和金属蒸气对熔滴的反冲力又阻碍了熔滴过渡 ,两者综合作用改变了熔滴过渡方式和过渡频率。在此基础上 ,通过对复合焊接过程中焊接电流和电弧电压波形以及熔滴过渡特征的分析 ,进一步研究了激光功率、激光与电弧的作用位置以及激光束离焦量对复合焊接过程中熔滴过渡频率的影响规律。

The experiments of CO_2 laser-MIG paraxial hybrid welding with 5.0mm-thick LF6 aluminum alloy plates have been made in the flat position. The experimental results indicate that, in a much wider parameter region, the CO_2 laser and MIG arc hybrid welding can improve the weld appearance, increase the weld penetration and width, and the porosity is also reduced significantly. At the same time, it was also found that the transfer mode and the inherent droplet transfer cycle time of conventional MIG arc are changed due to interaction between CO_2 laser and MIG arc in CO_2 laser-MIG hybrid welding process. Furthermore, according to the change of the MIG welding current and arc voltage waveform and the characteristics of droplet transfer in the hybrid welding process, the effect of laser power, the action point between laser beam and arc and the defocusing distance of laser beam on the frequency of droplet transfer was investigated in detail.