Interaction of CO 2 -laser radiation beam with electric arc plasma in hybrid (Laser + TIG) welding
Interaction of CO 2 -laser radiation beam with electric arc plasma in hybrid (Laser + TIG) welding
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混合（激光 TIG）焊接中 CO 2 激光辐射束与电弧等离子体的相互作用
DOI：
10.15407/tpwj2015.04.01
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发表时间：
2015
期刊：
影响因子：
--
通讯作者：
O. Mokrov
中科院分区：
文献类型：
--
作者：
I. Krivtsun;I. Krikent;V. Demchenko;U. Reisgen;A. Zabirov;O. Mokrov
建立了在惰性气体中运行、CO2激光聚焦光束沿弧柱传播的耐火阴极弧柱和阳极区等离子体中能量、质量和电荷传递的自洽数学模型。在这种系统中运行的过程的数学描述使用弧等离子体的单温模型，允许由于激光辐射吸收而产生的额外等离子体加热，以及与从阴极表面蒸发金属相关的多组分性质。分析了激光功率和阳极表面温度对耐火阴极弧柱和阳极区等离子体热特性和电磁特性的影响。结果表明，由于激光对弧光等离子体的局部加热，其弧柱旁轴区的温度比TIG焊各自的弧温提高5000~10000 K。这导致了弧柱近阳极区的电势和电流密度的空间分布以及电弧作用于阳极的热流密度的根本改变，从而改变了其对被焊金属的热和动态冲击的分布和整体特征。结果表明，在CO_2-激光+TIG复合焊接中，聚焦激光对电弧等离子体的冲击导致了电弧结合区域中心电流的收缩和电弧施加到阳极上的热流密度的相应增加。这促进了施加到金属上的能量的增加，这些能量在其熔化过程中被消耗，从而增加了激光-电弧热源的穿透性。结果表明，在聚焦激光照射下，阳极金属蒸发会导致近阳极区电流收缩效应的一定程度减弱。研究了在(CO2-激光+TIG)复合焊接条件下，激光在弧光等离子体中的吸收和折射对激光与其相互作用的特性及其对被焊金属表面热冲击的影响。结果表明，激光在弧光等离子体中的吸收会导致到达阳极表面的辐射功率有一定程度的下降。束流聚焦光斑在上述表面的大小几乎没有变化，即束流在弧光等离子体中的折射变得微不足道。参考文献11，表1，附图14。
Self-consistent mathematical model was proposed for the processes of energy-, massand charge transfer in the plasma of the column and anode region of electric arc with refractory cathode, running in inert gas, and exposed to a focused beam of CO2-laser radiation, propagating along the arc column. Mathematical description of the processes running in such a system uses single-temperature model of arc plasma, allowing for additional plasma heating due to laser radiation absorption, as well as its multicomponent nature, associated with metal evaporation from cathode surface. Influence of laser beam power and anode surface temperature on thermal and electromagnetic characteristics of plasma of the column and anode region of argon arc on refractory cathode was analyzed. It is shown that as a result of additional local heating of arc plasma by laser radiation, its temperature in the paraxial zone of arc column can rise by 5000—10000 K, compared to the respective arc in TIG welding. This leads to an essential restructuring of spatial distributions of electric potential and density of electric current in the arc column near-anode region, as well as density of thermal flow applied by the arc to the anode, thus changing the distributed and integral characteristics of its thermal and dynamic impact on the metal being welded. It is established that the impact of a focused laser beam on arc plasma leads to the effect of electric current contraction in the center of the region of anode binding of the arc and respective increase of the density of heat flow, applied by the arc to the anode, in hybrid (CO2-laser + TIG) welding. This promotes an increase of the energy applied to the metal, which is consumed in its melting and, therefore, an increase of penetrability of laser-arc heat source. It is shown that anode metal evaporation leads to a certain weakening of the effect of electric current contraction in the arc near-anode region, which is exposed to a focused laser beam. The influence of laser radiation absorption and refraction in arc plasma on the characteristics of laser beam interacting with it and its thermal impact on the surface of metal being welded under the conditions of hybrid (CO2-laser + TIG) welding was studied. It is shown that laser beam absorption in arc plasma leads to a certain decrease of radiation power, reaching the anode surface. The size of beam focusing spot on the above surface practically does not change, i.e. beam refraction in arc plasma turns out to be insignificant. 11 Ref., 1 Table, 14 Figures.