极性对自保护药芯焊丝电弧焊光谱特征的影响

由于自保护药芯焊丝具有抗风性以及优异的焊缝性能，已广泛应用于野外管道焊接以及大型机械的修复过程。电极极性是影响焊接过程的重要工艺参数。为了研究电极极性对电弧等离子体的影响机理，设计电弧等离子体空域中各点逐步扫描的同步采集系统，通过光谱特征谱线的分析，采用Stark谱线轮廓法计算电子密度，并且基于Boltzmann作图法计算电弧等离子体的温度，同时针对Al和Mg活性元素的分布特征进行分析。结果表明，靠近电极处，沿y轴负方向，直流正接时(焊丝接电源负极性),弧柱中心区电弧电子密度、电弧温度和活性元素呈现“水滴状”分布。而直流反接时(焊丝接电源正极性),弧柱中心区电弧电子密度、电弧温度和活性元素的分布特征表现为“手指状”分布。根据“自磁收缩”的原理，直流正接条件下，活性元素在径向方向受到的电磁力较小，整体分布呈现发散状。直流反接条件下，活性元素在径向方向受到的电磁力较大，收缩较为严重，整体表现为收缩状态。采用相同的电参数时，直流反接条件下弧柱中心区的电弧电子密度、电弧温度均大于直流正接条件下得到的电子密度和电弧温度，其中电子密度分布特征和带电粒子的电离程度是影响电弧温度的主要因素。在相同的电...

The Effect of Electrode Polarity on Arc Plasma Spectral Characteristics of Self-Shielded Flux Cored Arc Welding

Owing to the wind resistance and excellent weld bead performance of self-shielded flux cored wire. It has been widely used in pipeline welding and the repair of large machinery in the field. Especially, electrode polarity has a great effect on the welding process. In order to study the influence mechanism of electrode polarity on arc plasma, a synchronous acquisition system was designed to scan each point in arc plasma space. Through the analysis of characteristic spectra lines, the Stark profile method was used to calculate the electron density, and the arc plasma temperature was calculated based on the Boltzmann mapping method. At the same time, the distribution characteristics of Al and Mg active elements were analyzed. The results show that electron density distribution, arc plasma temperature and active elements in the central area of the arc column were like the water drop along the negative direction of the Y axis in DCEN (direct current electrode negative). Under the DCEP (direct current electrode positive), the distribution characteristics of arc plasma electron density, arc temperature and active elements in the central area of the arc column were fingerlike. According to the principle of self-magnetic contraction, the electromagnetic force was less in the radial direction under DCEP, and the distribution of active elements was divergent. Under DCEP, the active elements are subjected to more electromagnetic force in the radial direction, and the shrinkage was serious. In addition, the arc plasma electron density and arc temperature in the center of the arc column were higher in DCEP than those under DCEN when the same electrical parameters were used. The distribution characteristics of electron density and ionization degree were the main factors affecting the arc plasma temperature. The arc plasma temperature and electron density were raised with the current and voltage increase under the same electrode polarity.