摘要激光焊是一种用高能量密度的激光束作为焊接热源的熔焊方法，不仅具有高 的生产效率而且具有较高的焊接质量，是传统的熔焊方法无法比拟的。本文针对 3mm 的 T2 紫铜和 316L 不锈钢异种合金，采用激光焊的方法进行了焊接，研究 了激光功率（2~5kW）、焊接速度（0。6~1。5m/min）及激光光斑偏移量对焊缝成形 的影响，焊后通过接头的拉伸试验、显微硬度试验测试了接头的力学性能，并通 过 OM、SEM 和 EDS 观察和分析了异种合金激光焊接头不同部位的组织特征， 试验结果表明：80375

铜的熔化量对铜不锈钢异种金属焊接接头的力学性能具有显著影响。当激光 功率低于 2kW 时，由于铜熔化量不足，焊接接头的强度低于铜的母材强度。激 光光斑沿着焊缝中心或者偏向铜侧，激光功率超过 3。5kW， 焊接速度小于 1。5m/min 时，所得到的焊接接头具有较高的抗拉强度，达到 245MPa，拉伸试样 的断裂位置在铜母材上。

毕业论文关键词：铜；不锈钢；异种金属焊接；激光焊接；偏移量

Abstract Laser welding is a fusion welding method which use a high-energy density laser beam as the welding heat source。 It not only has high production efficiency but also has high welding quality。 It can not be replaced by the traditional welding methods。 This paper mainly studied laser welding process of copper and stainless steel, with a thickness of 3mm of T2 copper and 316L austenitic stainless steel test。 The aim of this article is to find the right welding parameters and to analyze the formation mechanism of welded joints。 In this test, by changing the laser power (2 ~ 5kW), welding speed (0。6 ~ 1。5m / min) and a laser spot offset, different properties of welded joints can be obtained。 Then using the tensile test and micro hardness test analyze the mechanical properties of welding joints。 And By OM, SEM and EDX element analysis to analyze the formation mechanism of joint。

The results showed that the amount of molten copper has a significant effect on the mechanical properties of the dissimilar metal weld joints。 When the laser power is lower than 2 kW, the strength of the welded joint is lower than the strength of the base material of copper because of the insufficient amount of molten copper。 When the laser spot irradiating the stainless steel side, even with a larger laser power (up to 4。5kW) and a smaller laser spot offset (offset 0。15mm), the strength of welded joints is still below the base material strength of copper, maximum only to 196MPa。 When the laser spot along the center of the weld or irradiating the copper side, the laser power exceeding 3。5KW and welding speed less than 1。5m / min, the welded joints have a high tensile strength, up to 245MPa and the tensile specimen fracture position is on the base material of copper side。

Keywords: copper, stainless steel, dissimilar metals, laser welding, offset

目 录

第一章 绪论 1

1。1 课题的研究背景与意义 1

1。2 铜/不锈钢异种材料焊接存在的问题 1

1。3 铜/不锈钢异种材料连接的研究现状 2

1。4 激光焊接的特点及原理 3

1。4。1  激光焊接的特点 3

1。4。2  激光焊的原理 4

1。4。3  激光深熔焊 5

1。5 本课题的主要研究内容 6

第二章 试验材料、设备及方法