穿孔等离子弧焊接弧与熔池的耦合模拟及正交分析

发布时间：2018-03-14 10:09

本文选题：等离子弧　切入点：焊接　出处：《金属学报》2015年11期 　论文类型：期刊论文

【摘要】：针对穿孔等离子弧焊接工艺,建立了定点焊的二维轴对称非稳态数理模型,描述高温流动的电弧与工件熔池的耦合输运过程,通过数值模拟获得了电场、磁场、流场与温度场的演变规律.模拟焊缝熔合线与实验结果吻合较好,验证了数学模型的合理性.研究结果表明:W阴极尖端附近的电流密度与温度是最高的;等离子弧在工件上部呈现出"钟形",而在中心轴线处因进入小孔呈细长的"锥形";高速Ar气等离子体冲击到小孔壁面时速度急剧降低,小孔内出现高压区和Ar气等离子体的返流现象;熔池内流动与传热的综合作用使焊缝熔合线呈倒"喇叭形".进一步对焊接的操作参数及焊枪结构参数进行了影响因素的正交试验模拟.极差分析表明,焊枪的结构因素比焊接操作参数更重要,即对电极间距、电极内缩量、喷嘴孔径需予以重点考虑,以获得良好的焊缝形状.
[Abstract]:A two-dimensional axisymmetric unsteady-state mathematical model of fixed-point welding is established to describe the coupling transport process between arc and molten pool in high temperature flow. The electric field and magnetic field are obtained by numerical simulation. The evolution of flow field and temperature field. The simulation welding seam fusion line is in good agreement with the experimental results, which verifies the rationality of the mathematical model. The results show that the current density and temperature near the tip of the W cathode are the highest. The plasma arc appears "bell shape" in the upper part of the workpiece, but at the center axis, it is "tapered" because of entering the orifice, and the velocity of high speed ar gas plasma crashing into the wall of the small hole decreases sharply. High pressure region and ar gas plasma reflux in the pore; The combined action of flow and heat transfer in the weld pool makes the weld fusion line appear as an inverted "horn". The orthogonal experimental simulation of the operating parameters and the structural parameters of the welding torch is carried out. The range analysis shows that, The structural factors of the welding torch are more important than the operating parameters of welding, that is, the distance between the electrodes, the amount of shrinkage in the electrode and the nozzle aperture need to be taken into account in order to obtain a good weld shape.
【作者单位】：北京科技大学机械工程学院;北京科技大学冶金工业节能减排北京市重点实验室;山东大学材料科学与工程学院;
【基金】：国家自然科学基金重点资助项目50936003~~
【分类号】：TG456.2

【参考文献】