摘要铝合金在工业制造中发挥着愈来愈重要的作用，应用范围逐渐扩大。但由于其特有 的物理化学特性，在焊接过程中常常伴随着气孔、裂纹等焊接缺陷，因此，铝合金焊接 技术的改进也成为重要的研究领域。本课题利用 SAF 焊机和日本 OTC 焊机，焊接 6mm 厚 的 3A21 铝合金，设计正交试验。结果验证了焊接工艺参数对焊缝的作用。焊接电流与送 丝速度具有线性关系，能够改变焊缝的熔深和余高；焊接电压的大小影响着焊缝熔宽的 尺寸，进而改变余高；焊接速度决定着填充金属的熔敷量，影响余高。另外对成形较好 的焊件进行金相观察和力学性能测试。发现焊缝的硬度大于母材和热影响区，热影响区 的硬度最低。在熔合线附近显微硬度有较大幅度的改变。74258

毕业论文关键词 铝合金 单丝 MIG 焊 OTC 焊机 显微硬度

Title  Experimental Investigation of single  wire MIG process of aluminum alloys

Abstract Aluminum alloy is playing a more and more important role in industrial manufacturing, and its application scope is gradually expanding。 However, due to its unique physical and chemical characteristics, the welding defects such as porosity, crack and so on are easy to be produced in the welding process, so the improvement of welding technology of aluminum alloy has become an important research area。 This investigation uses the SAF welding machine and the Japanese OTC welding machine to weld the 6mm thick 3A21 aluminum alloy, and designs the orthogonal experiment。 The effect of welding parameters on the welding process was verified。 Welding current and wire feeding velocity has a linear relationship, can change the weld penetration and reinforcement。 Welding voltage affects weld pool width and reinforcement。 Welding speed determines the amount of deposited metal filling, affects reinforcement。 In addition, metallographic examination and mechanical property test of the welded parts with good forming are carried out。 The hardness of the weld is higher than that of the base metal and the heat affected zone, and the hardness of the heat affected zone is lowest。 There is a significant change of the micro hardness near the fusion line。

Keywords  Aluminum alloy  Single wire MIG welding  OTC Microhardness

本科毕业设计说明书 第 I 页

目 次

1 引言 1

1。1 选题背景 1

1。2 研究现状 1

1。2。1 铝合金的焊接新技术 1

1。2。2 铝合金焊接焊缝组织和力学性能研究 2

1。2。3 铝合金的焊接缺陷控制 3

1。3 本课题研究内容 3

2 焊接材料及试验方法 5

2。1 焊接材料