摘 要
汽车后桥壳是汽车底盘上的关键零件。其内部安装有主轴减速器、半轴等零件，它承受汽车的重力并将车轮上的各种作用力通过悬架系统传给车架或车身。焊接是汽车车桥制造的主要工艺手段。
本文以汽车后桥壳焊接为研究对象，在介绍了其焊接技术概况、新技术及发展趋势的基础上，完成了汽车后桥壳优质低碳化结构钢16Mn材料的焊接性分析、焊接结构分析、焊接方法的选择及焊接材料的选用，设计出了合理的汽车后桥壳焊接工艺，并设计了自动焊方案。
通过分析选用了焊后焊缝综合力学性能更好、焊接成本更低的MAG焊工艺作为汽车后桥壳与半轴套管环缝的焊接方法，并采用埋弧自动焊作为桥壳纵缝的焊接方法。通过对优质低碳化结构钢16Mn的焊接性、产品结构特点及使用要求，分别确定了MAG焊及埋弧自动焊的焊接接头的形式、坡口角度以及焊接电流、焊接电压、焊接速度等焊接工艺参数。并通过对焊后焊缝中可腀@鱿值暮附尤毕堇嘈秃筒虻姆治觯徊教岢隽颂岣吆附又柿康拇胧员Ｖげ纺芑竦酶玫暮附又柿亢妥酆闲б妗Ⅻbr>
关键词：汽车后桥壳，焊接，埋弧自动焊，MAG焊
ABSTRACT
The real axle shield is a key part of chassis in automobile, inside which installs the spindle reducer, semiaxis and other parts. The shield can bear the gravity of automobile and transmit various forces from wheels to the auto frame or body via the suspension system. Welding is the main process means for manufacturing the vehicle axles.
Based on the research for welding vehicle axle shield, after having been introduced the profile of welding, new technology as well as the tendency of its development, this paper is focused on the analysis of high-quality low-carbon steel 16 Mn, the structure of welding, selection for welding methods as well as materials. the proper welding processing of axle shield and the auto-wielding schemes have been designed.
After thorough analysis, the MAG welding processing which can be obtained better comprehensive mechanical properties and lower costs for girth wielding has been selected for jointing the axle shield and the semiaxis sleeve girth. The unionmelt welding is also adopted as a processing for jointing the shield. Under the acquaintance of the high-quality low-carbon steel 16 Mn and its requirement for welding characteristics, series of parameters for MAG and unionmelt welding have been confirmed, such as the format of welding splice, veeangle, current, voltage and the speed of welding. Types of potential defects and their causes have also been studied. Thus measures for better welding processing to secure high qualities have been put forward.
Key words：The real axle shield, welding, unionmelt welding, MAG welding
目 录
中文摘要 Ⅰ
ABSTRACT Ⅱ
1绪论 1
1.1 焊接在汽车制造中的历史现状 1
1.2 我国汽车焊接工艺概貌 2
1.3 焊接在汽车后桥壳上在国内外的应用 4
1.4 本课题的研究内容及应用意义 5
2 汽车后桥壳产品焊接结构 6
2.1后桥的结构特点 6
2.2后桥的焊接结构 8
2.3后桥焊接残余应力的影响和消除 8
2.3.1焊接残余应力的形成 8
2.3.2焊接残余应力的影响 8
2.3.3焊接残余应力的消除 8
3汽车后桥壳材料的焊接性 9
3.1焊接裂纹的敏感性 9
3.1.1 16Mn冷裂纹 9
3.1.2热影响区脆化 10
3.2 16Mn焊接性的改进 11
4焊接方法和焊接材料的选用 12
4.1常用的焊接方法介绍 12
4.1.1手工电弧焊 12
4.1.2钨极氩弧焊（TIG焊） 13
4.1.3二氧化碳气体保护焊 14
4.1.4 MAG焊 15
4.1.5摩擦焊 16
4.1.6埋弧自动焊 17
4.2焊接方法的选择 17
4.3焊接设备的选择 19
4.3.1上下桥壳连接的焊接设备 19
4.3.2轴套管和桥壳的焊接设备 20
4.4焊接材料的选择 20
5焊接工艺设计 21
5.1焊接接头及坡口的设计 21
5.2埋弧自动焊焊接规范参数设计 22
5.3 MAG焊的焊接参数设计 23
6自动焊方案设计 25
6.1工艺流程 25
6.2设计思想 25
6.3主要装备组成 25
6.4控制系统 26
7结论 28
参考文献 29
