摘要
目的研究外加纵向磁场对倾斜电极TIG焊接的电弧温度分布、流动模式和工件所受热力作用的影响。方法建立磁场-电弧复合焊接热、电、磁、流动的三维数学模型。通过数值模拟和高速摄像实验,揭示倾斜电极电弧在外加磁场作用下的流动、形貌及温度演化机制。结果外加纵向磁场后,电弧流动速度明显增加,流动模式由沿电极方向喷射变为近似沿竖直方向旋转向下的流动模式;电弧对工件的热作用均匀性提高,热作用中心向电极正下方靠近,但在焊接横向方向上存在偏离;工件受到表面的电弧旋转拖拽力和内部的旋转洛伦兹力作用,最大洛伦兹力可达50 000 N/m^(3)。结论基于所建立数学模型的模拟结果与实验电弧形貌吻合良好,结果表明,外加纵向磁场能够显著改变电弧的形态及流动模式,提高电弧热流密度的均匀性,并能够对熔池产生有效的搅拌作用。
The work aims to study the influence of an external magnetic field on arc temperature distribution, flow pattern and thermal action of workpiece in TIG welding with inclined electrode. A three-dimensional mathematical model of heat, electricity, magnetism and flow in magnetic field-arc hybrid welding was established. Through numerical simulation and high-speed camera experiments, the flow, morphology and temperature evolution mechanism of arc of TIG welding with inclined electrode under external magnetic field were revealed. After the longitudinal magnetic field was applied, the arc flow speed increased and flow pattern changed from a spray mode along the electrode direction to a downward flow pattern which was approximately rotating in the vertical direction. The uniformity of the heat input of the arc to the workpiece was improved, and heat center approached directly below the electrode, but deviated from the horizontal welding direction. The workpiece was subject to the arc rotating drag force on the surface and the internal rotating Lorentz force, and the maximum Lorentz force reached 50 000 N/m^(3).The simulation results based on the established mathematical model are in good agreement with the morphology of the experimental arc. The results show that the external longitudinal magnetic field can significantly change the shape and flow pattern of the arc, improve the uniformity of the arc heat flux, and can effectively stir the molten pool.
作者
母中彦
胡仁志
庞盛永
MU Zhong-yan;HU Ren-zhi;PANG Sheng-yong(State Key Laboratory of Materials Processing and Die&Mould Technology,Huazhong University of Science and Technology,Wuhan 430074,China)
出处
《精密成形工程》
北大核心
2021年第6期123-129,共7页
Journal of Netshape Forming Engineering
基金
国家重点研发计划(2017YFB1103100)。
关键词
复合焊接
电弧焊接
等离子体
磁场
数值模拟
hybrid welding
arc welding
plasma
magnetic field
numerical simulation
