铝合金薄板电子束穿透焊熔池的数值模拟
发布时间：2018-12-14 10:46
【摘要】：为有效地控制电子束焊接后的焊缝成形,得到符合要求的焊接结构,本文基于电子束焊接熔池物理过程的分析,使用有限体积法(FVM)数值模拟软件Fluent,对2mm厚的2219铝合金电子束穿透焊的温度场和流场进行数值模拟,研究了电子束穿透焊时熔池的流动行为及规律.模拟结果表明,电子束焊接形成穿透型匙孔时,熔池中液态金属的流速大小和方向迅速发生改变,最大流速可以达到10 m/s;产生的金属蒸汽反冲压力会使熔池剧烈震荡,熔池中远离匙孔的液态金属在Marangoni对流的驱动下,使熔池上、下两部分形成了较中间部分更长、更不稳定的拖尾,同时促进了熔池宽度的增加;熔池宽度和熔池拖尾长度分别在35 ms、90 ms左右达到了稳定.模拟焊接熔池凝固后,正面焊缝有一定的余高,背面焊缝有一定的收缩,其表面焊缝形态与实际焊缝形态吻合良好.此外,通过对熔池中液态金属的流速分析,还可以得出结论:金属蒸汽反冲压力对熔池的驱动作用远大于重力和表面张力的影响.
[Abstract]:In order to effectively control the weld formation after electron beam welding and obtain the welding structure that meets the requirements, based on the analysis of the physical process of electron beam welding molten pool, the finite volume method (FVM) numerical simulation software Fluent, is used in this paper. The temperature field and flow field of electron beam penetration welding (EBW) of 2219 aluminum alloy with 2mm thickness were numerically simulated. The simulation results show that the velocity and direction of liquid metal in the molten pool change rapidly when the electron beam welding forms the penetrating keyhole, and the maximum velocity can reach 10 Ms. The resulting recoil pressure of the metal vapor can cause a sharp oscillation in the molten pool, where liquid metal far from the keyhole is driven by the Marangoni convection, resulting in the formation of a longer, more unstable tail on the bottom of the pool than the middle part. At the same time, the width of the molten pool is increased. The width of the weld pool and the tail length of the weld pool are stable at about 35 ms,90 ms. After simulated weld pool solidification, the front weld has a certain excess height, the back weld has a certain shrinkage, and the surface weld shape is in good agreement with the actual weld shape. In addition, by analyzing the flow rate of liquid metal in the molten pool, it can be concluded that the effect of metal vapor recoil pressure on the driving effect of molten pool is much greater than that of gravity and surface tension.
【作者单位】： 先进焊接与连接国家重点实验室(哈尔滨工业大学);
【分类号】：TG456.3
本文编号：2378479
[Abstract]:In order to effectively control the weld formation after electron beam welding and obtain the welding structure that meets the requirements, based on the analysis of the physical process of electron beam welding molten pool, the finite volume method (FVM) numerical simulation software Fluent, is used in this paper. The temperature field and flow field of electron beam penetration welding (EBW) of 2219 aluminum alloy with 2mm thickness were numerically simulated. The simulation results show that the velocity and direction of liquid metal in the molten pool change rapidly when the electron beam welding forms the penetrating keyhole, and the maximum velocity can reach 10 Ms. The resulting recoil pressure of the metal vapor can cause a sharp oscillation in the molten pool, where liquid metal far from the keyhole is driven by the Marangoni convection, resulting in the formation of a longer, more unstable tail on the bottom of the pool than the middle part. At the same time, the width of the molten pool is increased. The width of the weld pool and the tail length of the weld pool are stable at about 35 ms,90 ms. After simulated weld pool solidification, the front weld has a certain excess height, the back weld has a certain shrinkage, and the surface weld shape is in good agreement with the actual weld shape. In addition, by analyzing the flow rate of liquid metal in the molten pool, it can be concluded that the effect of metal vapor recoil pressure on the driving effect of molten pool is much greater than that of gravity and surface tension.
【作者单位】： 先进焊接与连接国家重点实验室(哈尔滨工业大学);
【分类号】：TG456.3
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，本文编号：2378479
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