熔池表面形状对电弧电流密度分布的影响

电弧电流密度分布决定着电弧热流密度、电弧压力的分布，是了解焊接电弧物理本质，建立 焊接过程数学模型的基础.根据电弧物理的基本原理，建立了电弧电流密度在变形熔池表面 上的分布模型，定量分析了熔池表面形状对电流密度分布的影响规律.计算表明，电流密度 在电弧中心线附近呈双峰分布，在离开电弧中心线一定距离处变为单峰分布，熔池表面形状 对电流密度分布有明显的影响.基于该模型计算的焊缝几何形状与实测结果符合得较好.关键词：熔池表面变形电流密度分布模型

THE INFLUENCE OF WELDPOOL SURFACE SHAPE ON THE DISTRIBUTION OF ARC CURRENT DENSI TY

The distribution mode of arc current density determines the distribution modes o f both arc heat flux and arc pressure, which are the basis to understand the phy sical nature of welding arc and to establish the mathematical model of welding p rocesses. Based on the general principle of arc physics, a distribution model of current density on the deformed weldpool surface is established in this paper. Quantitative analysis is carried out to determine the influence of weldpool surf ace shape on the distribution of current density. The predicted results show tha t the distribution of current density is bimodal distribution near the arc cente rline, and that with increasing distance from the arc centerline the bimodal dis tribution is gradually diminished. The distribution mode of current density is m arkedly modified by the shape of weldpool surface. According to this distributio n model, the predicted weld geometry is in agreement with the measured one.