镁合金钨极氩弧焊焊接电弧电势与电流密度的数值模拟

为了分析钨极氩弧焊(GTAW)焊接电弧电势与电流密度在三维电弧空间内的分布,以镁合金的GTAW焊接电弧为研究对象,建立了包含焊丝、焊接电弧以及工件的三维瞬态联合数值模型,对电弧等离子体的电场进行了数值计算,之后得到了电弧电势与电流密度在电弧空间的分布。研究结果表明:在整个电弧空间中电极端部的电势梯度最大,并在此处产生了最高的电流密度。在焊接条件稳定的前提下,电极正下方对称轴线上电流密度最大,弧柱中心处的电流密度要高于周边区域。电弧横断面上的电流密度在弧长1,2,3,5mm处及工件表面上均符合高斯分布。

Numerical Simulation of Electric Potential and Current Density in a Gas Tungsten Arc Welding Arc of Magnesium Alloy

In order to analyze the distribution of electric potential and current density in the three-dimensional(3D) arc space,a united 3D transient numerical model is established for a magnesium alloy gas tungsten arc welding(GTAW) arc to study the electric potential of arc plasma,which covers the electrode,welding arc and workpiece.After that,the distribution of electric potential and current density in the arc space are obtained.The results indicate that the greatest gradient of electric potential in the whole arc space exists around the electrode tip,thus the biggest electric current density comes into being there.It is also predicted that in the arc space the current density has the maximum value around the extending center line of the electrode under a condition of stable welding parameters.Therefore,current density in the center of the arc column is larger than that in the surrounding area.Finally,the distribution of current density in cross section of arc is consistent with Gaussian distribution at 1,2,3,5 mm arc length and arc-metal interface.