基于图像分析的焊接电弧空间电流密度分布测量

焊接电弧空间电流密度分布是反映电弧热-力耦合作用、影响焊接冶金与成形质量的重要因素之一.文中提出了一种针对非熔化极气体保护焊（gas tungsten arc welding, GTAW）电弧的电流密度空间分布的测量方法:首先通过拍摄GTAW电弧在一定特征谱线波长上的图像，利用标准温度法计算得到电弧空间温度场的分布；然后通过建立电势场偏微分方程，根据温度与电导率的关系、边界条件、截面电流守恒条件，求解得到电流密度分布.经对比，该方法计算所得电流密度与文献中同等条件试验测得数据具有较好的一致性.该方法采用非侵入式方法实现电弧电流密度分布的测量，为实现焊接过程的实时监测和质量控制提供了技术基础.

Spatial distribution measurement of gas tungsten arc current density based on image analysis

The spatial distribution of the arc current density is one of the key factors for revealing the thermal-force coupling in the welding process which determines the metallurgy and forming quality. A method to measure the spatial distribution of gas tungsten arc (GTA) current density was proposed. The GTA images acquired by monochromatic imaging were analyzed to calculate the temperature field using the Fowler-Milne technique, and then the spatial distribution of the current density was obtained by solving the partial differential equation of electric potential with the constraints such as the relationship between temperature and conductivity, the corresponding boundary conditions and the current conservation conditions, and so on. The result has good consistency with the data measured under the same experimental conditions in literature. The proposed method is able to measure the spatial distribution of the GTA current density in a non-invasive way, and therefore provides a basis for techniques of real-time monitoring and quality control of the welding process.