熔化极气体保护焊焊缝成形研究（本科毕业论文设计）.doc

摘 要

熔化极气体保护焊（GMAW）是焊接生产中最常用的焊接方法之一。由于熔化极气体保护焊广泛用于各行各业焊接结构的生产，其产品品质倍受人们关注。焊缝几何尺寸是焊接质量的重要影响因素，如何使焊缝达到要求的形状和尺寸，是焊接生产中必须解决的问题。
本文通过分析焊接工艺规范参数对焊缝成形的影响，来探讨焊接工艺与焊缝成形之间的关系。焊接工艺因素包括焊接电流、电弧电压、保护气体流量、焊丝伸出长度等。焊接工艺因素的改变会影响电弧的热输入进而引起焊缝尺寸和形状的变化并影响到焊接质量。本文分析了焊接电流、电弧电压、保护气体流量和焊丝伸出长度等焊接工艺因素对焊缝成形影响的规律。
保护气体成分的不同会引起电弧特性的变化，进而对焊缝成形产生影响。本文分析了保护气体成分的不同配比对熔化极气体保护焊的焊接稳定性影响。
焊丝伸出长度的变化通过对焊丝金属产热的影响能改变焊缝几何尺寸，本文分析了不同的焊丝伸出长度对焊缝成形影响的规律。


关键词：熔化极气体保护焊、焊接工艺参数、保护气体流量、焊缝几何尺寸、焊丝伸出长度
















ABSTRACT

Gas Metal Arc Welding (GMAW) is the dominant welding process. Given that GMAW is widely applied to welding structure, its product quality is paid more attention. Weld geometry size is one of the influence factors for welding quality .It is more important to make the welding shape proper.
By analyzing the welding parameters in pacts on the welding shape, this paper studies the relation between welding parameters and welding shape. Welding process factors consist of welding electric current, electric are voltage, welding speed, etc. The changing of welding process factors would result in the change of welding size and shape, and have effects on hot input and Welding quality .This passage analyzes the law of the effects which welding process factors have on welding shaping.
Changing the shielding gas, the characteristic of arc is changed too. The welding shape will be changed with the shielding gas’s changing. The passage analyzes the different proportion of shielding gas in pacts on the welding technology performance and quality in GMAW.
Different extensions have effects on resistance heat, and change the weld size and shape. This passage analyzes the different extensions in pacts on the weld geometry sizes.


Key words： GMAW, welding parameters, shielding gas flow, weld geometry sizes, electrode extension











目 录
摘 要 I
ABSTRACT I
目 录 II
1 绪论 1
1.1熔化极气体 保护焊应用概况 1
1.2焊接电弧 1
1.2.1电弧本质 1
1.2.2 电弧中的带电粒子 2
1.2.3 焊接电弧的产生 2
1.2.4 焊接电弧的结构与温度 3
1.2.5 焊接电弧特性 4
1.2.6 电弧力及影响因素 5
1.2.7焊接电弧的稳定性 6
1.3本课题的研究内容、目的 7
1.3.1研究目的 7
1.3.2研究内容 8
2 试验方案设计 9
2.1试验设备 9
2.2试验窗口 10
2.3试验条件 11
3 试验过程 12
3.1 实验中应注意的问题 12
3.2试验结果 12
4 试验结果分析 15
4.1 CO2短路过渡试验结果分析 15
4.1.1 焊接电流的影响 15
4.1.2 电弧电压的影响 20
4.1.3 保护气体流量的影响分析 24
4.2 Ar+CO2混合气体射流过渡实验结果分析 24
5 结论 27
致谢 28
参考文献 29