摘要随着工业制造业的发展，焊接结构日趋大型化、高参化，厚壁及超厚壁焊接金属结 构件的应用越来越广泛，同时对其焊接技术的要求也越来越高。由于摇动电弧窄间隙 GMAW 焊接过程具有结构紧凑、方向性比较好、变形小、成本低、生产率高等优点， 同时摆动电弧窄间隙 GMAW 焊可以提高侧壁热输入，解决侧壁未熔合，因此摇动电弧 窄间隙 GMAW 已经成为超厚板焊接的首选方法。由于摇动电弧窄间隙 GMAW 焊接过 程中的工艺参数较多，难以优化，焊接参数搭配合适可以减少焊缝缺陷，且目前对摇动 电弧窄间隙 GMAW 焊的研究机理比较少，熔池流体流动与焊缝成型有着密切的关系， 所以对摇动电弧窄间隙 GMAW 焊的熔池流体流动进行研究。83346

本文综合考虑摇动电弧窄间隙 GMAW 焊接头的几何特征和热源移动的路径特点， 依据质量守恒定律、能量守恒定律、动量守恒定律等基础建立了适合摇动电弧窄间隙 GMAW 的三维数值分析模型，利用 Fluent 软件对结果进行模拟计算，基于计算结果对 摇动电弧窄间隙 GMAW 焊流体流动进行分析，分析熔池的流体流动行为，对熔池尺寸 的计算结果与实验结果进行比较，研究结果表明：实验结果与模拟结果的熔宽尺寸和侧 壁熔深尺寸相同，从而说明了模型的准确性，从表 3-2 中可以看到，模拟结果的熔深尺 寸大于实验结果的熔深尺寸，说明模型也存在微小偏差，这也是模型需要改进的地方。 当电弧刚移动到右侧时，金属液体向上流，熔池右侧的金属向左侧流时同时分为了两个 方向，其中一部分向下流，另外一部分向着熔池低落的方向流去，焊缝横截面图底部呈 现明显的哑铃状形态，熔池底部峰值向左移动，说明熔池中的流体在电弧压力的排挤作 用下向新的熔池流动。

毕业论文关键词：摇动电弧；窄间隙；GMAW；热源模型；熔池行为

Abstract With the development of industrial manufacturing, welding structure is becoming more and more large, the Senate, wall thickness and ultra thick wall weld metal structure parts are used more and more widely, and the welding technical requirements are also getting higher and higher。 As a result of shaking arc narrow gap GMAW welding process has compact structure and the direction of good, small deformation, low cost, high productivity advantages, while swinging arc narrow gap GMAW welding can improve the side wall of the heat input, to solve the lack of sidewall fusion, so shake arc narrow gap GMAW has  become  the preferred method for ultra thick plate welding。 As a result of shaking arc narrow gap gap GMAW welding process there are a lot of technological parameters to excellent And welding parameters appropriate collocation can decrease the weld defects and the swing arc narrow gap GMAW welding mechanism of relatively small, of fluid flow in the molten pool and weld formation has a close relationship, so to shake the arc narrow gap GMAW weld  pool  fluid flow was studied。

Considering the swing arc narrow gap GMAW welding head and the geometric characteristics of the moving heat source path characteristics, according to the law of conservation of mass, conservation of energy law, the law of conservation of momentum and foundation is established for rocking arc narrow gap GMAW three-dimensional numerical analysis model, using FLUENT software the results of simulation calculation, based on the results of calculation analysis for the swing arc narrow gap GMAW welding fluid flow, different parameters and different conditions of fluid flow in the molten pool were analyzed, size of molten pool of the calculated results and the experimental results are compared, research results show that: experimental results and the calculated results of the weld width size and side To the exclusion of fluid in the shift to the left, at the bottom of the flow direction of flow to the left on the right side of the wall penetration of the same size, but the penetration depth of different sizes, from table 3-2 in can see, the calculation results of penetration depth size is larger than the experimental results of penetration size, so that the model accuracy, but there is still a small deviation, which is the model needs to be improved。 When the arc had just moved to the right, the metal liquid up flow, molten pool of metal at the same time points to two direction, one part to dirty, another part towards the molten pool are low to weld cross section showed the dumbbell shape of molten pool at the bottom of the peak, indicating that the molten pool arc pressure new molten pool flow。