TIG焊电弧-熔池传热与流动数值模拟

发布时间：2018-05-27 02:17

本文选题：钨极惰性气体保护焊 + 统一模型　；参考：《机械工程学报》2015年10期

【摘要】：针对钨极惰性气体保护(Tungsten inert gas,TIG)焊,采用一组满足整个求解域的偏微分方程组和合理的边界条件,建立包括钨极、电弧和母材的三维瞬态统一模型。以SUS304不锈钢为母材,求解获得电弧-电极(熔池)的温度场、流场、压力、电流密度、电磁力等结果,并与已有的试验结果和其他相关的研究结果做对比。在此基础上,通过分析阳极热输入,求得焊接热效率为86.3%。重点比较浮力、电磁力、等离子流拉力和Marangoni剪切力单独作用下的熔池流动特性,并将计算结果和格拉晓夫数Gr、磁雷诺数Rm和表面张力雷诺数Ma相结合,分析了这几种驱动力的相对作用大小,将计算结果和Peclet数Pe相结合强调了熔池热对流与热传导的相对作用。结果表明,与等离子拉力和Marangoni剪切力相比,浮力和电磁力对熔池对流的作用较小;等离子拉力和Marangoni剪切力处于同一数量级,而Marangoni剪切力大于等离子流拉力,两者共同作用使熔池表面金属由内向外流动。与热传导相比,熔池金属这种向外流动导致的热对流主导传热过程,是造成TIG焊宽而且浅的焊缝形貌的本质原因。
[Abstract]:For tungsten inert gas shielded Tungsten inert gas (TIG) welding, a set of partial differential equations and reasonable boundary conditions satisfying the whole solution domain are adopted to establish a three-dimensional transient unified model including tungsten electrode, arc and base metal. The results of temperature field, flow field, pressure, current density and electromagnetic force obtained by using SUS304 stainless steel as the base metal were calculated and compared with the experimental results and other related research results. On this basis, by analyzing the anodic heat input, the welding heat efficiency is obtained to be 86.3. The characteristics of molten pool flow under the action of buoyancy, electromagnetic force, plasma flow tension and Marangoni shear force are compared, and the calculated results are combined with Graschev number, magnetic Reynolds number RM and surface tension Reynolds number Ma. The relative action of these driving forces is analyzed, and the relative effect of heat convection and heat conduction in the molten pool is emphasized by combining the calculated results with the Peclet number Pe. The results show that the effect of buoyancy and electromagnetic force on molten pool convection is smaller than that of plasma tension and Marangoni shear force, and the plasma tension and Marangoni shear force are in the same order of magnitude, while the Marangoni shear force is larger than the plasma flow shear force. The combined action of the two causes the flow of metal on the surface of the molten pool from the inside to the outside. Compared with heat conduction, the heat convection dominating heat transfer process caused by the outward flow of molten pool metal is the essential reason for the wide and shallow weld appearance of TIG welding.
【作者单位】：兰州理工大学甘肃省有色金属新材料省部共建国家重点实验室;兰州理工大学有色金属合金及加工教育部重点实验室;
【基金】：国家自然科学基金资助项目(51074084,51205179)
【分类号】：TG444.74

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