等离子焊接电弧电流密度分布模型

Distribution model for current density of plasma welding arcs

采用分裂阳极法对于不同压缩状态的焊接电弧进行测试,将大量测试结果应用概率统计知识在概率纸上进行拟合检验,发现阳极平面电流密度分布精确地服从威布尔分布规律。在分裂阳极测定基础上建立的威布尔二维联合分布密度函数可以作为阳极平面电流密度分布的数学模型。运用这一模型可以求得阳极平面任一点的电流密度,这一模型在电弧中心部分与正态模型十分接近,但在偏离中心处,则具有较高的精确性,且能确定电弧边界,而这一点正态模型是无法做到的。

In this paper, the partitioned an(?)de method is used to measure welding arcs compressed in different conditions, and the experimental records are put on various probability papers to be examined with the principles of probability theory and statistics, It was found that the distribution patterns of current density are in consistence with the regularity of Weibull distribution, A two-dimantional Weibull distribution density function, established on the basis of measurement with the partitioned anode, may be regarded as a common modef for the distribution of current density on the anode plane. By means of this mathematical model, the current density at any point of the anode plane can be calculated. In the central part of the arc dross-section, the calculation values from this model are close to those from the model of normal distribution, but, in the outlying part of the arc cross-section, this model gives more accurate results than those from the model of normal distribution. Furthemore, with this model the arc border can be determined clearly, which is impossible to be achived with a normal distribution density function.