摘要作为一种轻质材料，铝合金具有密度低、强度高、热电导率高、耐腐蚀能力 强等特性；其焊接结构被广泛应用于工业制造领域。但铝合金焊接较为困难，易 出现气孔、裂纹等缺陷，且应力及变形较大；传统的 MIG 焊及高能密度激光都 无法实现其优质、高效焊接接头。80638

而激光+MIG 复合焊热源焊综合了激光焊和 MIG 焊的双重优点,克服了两者 的不足，具有提高铝合金焊接质量及效率的巨大潜力。但相较于单热源焊接工艺， 复合焊工艺参数较多，难于优化，因此，研究激光-电弧复合焊主要工艺参数对 焊缝成形的影响规律，有助于该新型焊接技术的推广应用，同时为其内部机理研 究提供基础实验数据，具有重要的学术价值和工程意义。

本文主要通过试验方法对 6mm 厚 6061 铝合金光纤激光+MIG 焊工艺进行研究，分析了激光功率、焊接电流、焊接速度、激光与电弧相对位置等主要参数对 焊缝形状尺寸、组织性能的影响。结果表明：当激光个功率由 200W 提高到 5000W， 其熔深则由 1。5mm 增大到 4。5mm，但熔宽变化有限；而当电弧功率增大时，则 主要熔宽增大；相较于激光前置设置，当激光在后而电弧在前时，熔深相对较大。 焊接接头部分的热影响区会出现软化过时效区，使得焊接接头硬度明显降低，焊 缝区晶粒细小，而热影响区组织非常复杂，晶粒尺寸不均匀性非常明显。

毕业论文关键词：铝合金，光纤激光，复合焊接，焊缝成形

Abstract As a lightweight material, aluminum alloy with low density, high strength, thermal conductance rate is high, strong corrosion resistance and other properties; the welding structure is widely used in industrial manufacturing field。 But aluminum  alloy welding is difficult, easy pores, cracks and other defects, and the stress and deformation larger; traditional MIG welding and high energy density laser are unable to achieve the high-quality, efficient welding joint。

And laser MIG hybrid welding welding integrated dual advantages of laser welding and MIG welding, overcomes the shortcomings of the two, can improve the aluminum alloy welding quality and efficiency of its huge potential。 But compared to the single welding technology, hybrid welding technology parameter is more, is difficult to optimize。 Therefore, the research study of laser arc hybrid welding process parameters influence on the formation of weld, contribute to the popularization and application of the new welding technology, provide basic experimental data for the research on the internal mechanism at the same time, has important academic value and engineering significance。

This paper mainly through the test method of 6mm thick alloy fiber laser +MIG welding process of 6061 aluminum were studied, analysis of the laser power, welding current, welding speed, the size of the main parameters of laser and arc position on weld shape, affect the organization performance。 At the same time, the use of computer simulation technology of numerical machine, welding temperature field of aluminum composite properties the alloy was analyzed。 The results show that when the laser power is increased to KW?, its penetration depth is increased from mm to mm, but the weld width changes limited; and when the arc power increases, the main weld width increases; compared to the laser pre setting, when the laser in after the arc in front, melting deep is relatively large。 The welding heat affected zone of joint part will appear over aging softening zone, the hardness of welded joints decreased, weld grains and the microstructure in heat affected zone is very complex, uneven grain size

is very obvious

Keywords：Aluminum alloy, optical fiber laser, hybrid welding, weld formation

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