基于光谱诊断的氧化物活性TIG焊电弧特征分析

Analysis of Arc Characteristics in Oxide Active TIG Welding Based on Spectroscopy Diagnosis

活性钨极氩弧焊(A-TIG焊)作为一种新型的焊接方法,通过在母材表面预先涂覆活性剂来增加焊缝熔深、提升焊接效率,在实际生产中已经得到了广泛的应用。氧化物作为A-TIG焊中最为常见的活性剂配方之一,其影响电弧行为的机制目前仍存在一定争议。为明晰氧化物对TIG焊电弧行为的影响机制,文中搭建了电弧形态与电弧空域光谱同步采集系统,研究了氧化物作用下电弧空域中活性剂粒子及氩、铁等带电粒子的谱线分布规律和电弧形貌特征,并基于Boltzmann作图法计算了不同区域的电弧电子温度。研究发现:电弧空间中的ArⅡ谱线相对强度随距阴极区距离的增大逐渐减小,这是因为越靠近阴极区电弧能量密度越集中,越有利于促进Ar原子的电离;SiO_(2)、B_(2)O_(3)能够促进Ar粒子的电离,TiO_(2)能够抑制Ar粒子的电离;FeⅡ谱线相对强度在轴向方向的分布规律与ArⅡ谱线的相反,从阳极区附近到阴极区附近,谱线相对强度逐渐减小,这是因为越靠近熔池表面(阳极区附近),蒸发进入到电弧空间的铁蒸气浓度越高、电离越明显;3种氧化物活性剂的引入都会使FeⅡ谱线的相对强度降低。涂覆TiO_(2)活性剂的电弧空间中并未检测到明显的TiⅠ特征谱线和电弧收缩现象,且电弧温度场并未发生明显的变化,因而TiO_(2)活性剂对电弧行为的影响非常微弱;涂覆SiO_(2)、B_(2)O_(3)活性剂的电弧空间中都检测到了SiⅠ、BⅠ特征谱线,且两种活性剂能够引起电弧收缩,但电弧收缩并不会对电弧温度场产生明显的影响。

As a new welding method,active tungsten argon arc welding(A-TIG welding),which increases weld penetration and improves welding efficiency by coating active agent on the surface of base metal,has been widely used in actual production.As one of the most common active flux formulations in A-TIG welding,oxide’s influence mechanism for arc behavior is still in debate.In order to clarify the influence mechanism of oxide on the arc behavior of TIG welding,a synchronous acquisition system of arc morphology and arc spatial spectrum was established.The spectral line distribution and arc morphology characteristics of active agent particles,argon,iron and other charged particles in the arc spatial space under the action of oxide were studied,and the arc electron temperature in different regions was calculated based on Boltzmann mapping method.It is found that the relative intensity of ArⅡspectral lines in the arc space decreases gradually with the increase of the distance from the cathode region.This is because the closer the arc is to the cathode region,the more concentrated the arc energy density is,the more favorable it is to promote the ionization of Ar atoms.SiO_(2)and B_(2)O_(3)can promote the ionization of Ar particles,while TiO_(2)can inhibit the ionization of Ar particles.The distribution law of the relative intensity of FeⅡspectral lines in the axial direction is opposite to that of ArⅡspectral lines.The relative intensity of the spectral lines gradually de⁃creases from the vicinity of the anode region to the vicinity of the cathode region.This is because the closer it is to the surface of the molten pool(near the anode region),the higher the concentration of iron vapor evaporated into the arc space is and the more obvious the ionization is.The introduction of three kinds of oxide active agents can reduce the relative intensity of FeⅡspectral lines.In the arc space coated with TiO_(2)active agent,no obvious TiⅠcharacteristic line and arc contraction phenomenon were detected,and the arc temperature field did not change sig⁃nificantly,which means that the influence of TiO_(2)active agent on the arc behavior is very weak.The characteristic spectral lines of SiⅠand BⅠwere detected in the arc space coated with SiO_(2)and B_(2)O_(3)active agents,and the two ac⁃tive agents can cause arc contraction,but the arc contraction has no obvious effect on the arc temperature field.