摘要本文以车身轻量化为研究背景，提出了活性激光焊接铝合金的相应优势。进行不同工艺参数对于焊缝硬度以及Mg元素烧损的影响进行了分析，同时简要说明了焊缝中Mg元素含量与焊缝硬度的关系。78229

试验结果表明：改变激光功率、焊接速度，涂敷活性剂下焊缝区平均硬度均高于未涂敷活性下焊缝区平均硬度。涂敷活性剂的焊缝硬度随着激光功率、焊接速度的增大先增大后减小，随离焦量的增加而变大；未涂敷活性剂下焊缝平均硬度随离焦量、激光功率的增大而减小，却随着焊接速度的增大而增大。铝合金活性剂对接焊焊缝中，焊缝熔合区Mg含量较高，从母材到焊缝区Mg的含量降低，Si的含量增加；无活性剂下从母材到焊缝区Mg的含量略有减小，Si的含量明显减少，Al的含量略有增加。涂敷与未涂敷活性剂的焊缝中Mg元素含量都随着离焦量、激光功率和焊接速度的增大而减小。未涂敷活性剂时，焊接工艺参数变化时，Mg元素的含量降低，相应的焊缝硬度也降低。但当涂敷活性剂时，只有在焊接速度变化时，Mg元素的含量变化才与焊缝硬度变化趋势相一致。而当离焦量和激光功率发生变化时，在Mg元素含量降低时，相对应的焊缝硬度都存在一个先增大后减小的过程。

毕业论文关键词：活性激光焊；Mg元素；铝合金

Abstract In this paper, the light weight of the body is studied, and the corresponding advantages of active laser welding of Aluminum Alloy are presented。 Different process parameters of the hardness of the weld and the influence of evaporation loss of Mg element are analyzed, and briefly explains the relationship between weld Mg element content and the hardness of the weld。

The experimental results show that the average hardness of the weld zone is higher than the average hardness of the laser power and welding speed with the coating of the active agent。 Coated active agent weld hardness increases at first and then decrease with the laser power, welding speed, with the increasing amount of coke from the larger, uncoated active agent under the average weld hardness decreases with from defocus, laser power increases, and increases with the increasing of welding speed。 Active agent Aluminum Alloy butt weld, the weld fusion zone with higher Mg content, from the parent metal to the weld zone of Mg content decreased, increased the content of Si; no active agent from the parent metal to the weld zone of Mg content decreased slightly, Significantly reduced the content of Si, Al content increased slightly。 The content of Mg element in the weld of the coated and uncoated active agent decreases with the increase of the amount of the laser power, the laser power and welding speed。 When the welding parameters are changed, the content of Mg element decreases, and the hardness of the welding seam is decreased。 But when the application of the active agent, only when the welding speed change, the content of the Mg element is consistent with the change of the weld hardness。 When the amount of the laser and the laser power are changed, the hardness of the weld has a first increase and then decrease with the decrease of the Mg element content。

Key words : active laser welding; Mg element; Aluminum alloy

目录

第一章  绪论 1

1。1课题研究背景 1

1。2铝合金焊接现状及存在问题 2

1。3焊接方法 3

1。3。1激光焊 3

1。3。2活性TIG焊 5

1。3。3活性MIG焊 5

1。3。4活性激光焊