摘要焊接技术在当代工业领域有着至关重要的作用，焊接技术的更新与发展对现代工 业发展有极大的推动作用，在汽车、航空、船舶等领域对焊接技术的要求也越来越高。 随着科技的发展，激光—MIG 复合焊作为两种焊接方法的集合体，它结合了电弧焊 和激光焊的优点，具有非常好的焊接特性，这种焊接方法很值得研究探索。80923

本课题选取了 Q235 钢作为研究对象，采用 H08Mn2SiA 焊丝，采用激光-GMAW 复合焊的焊接方法对试板进行对接焊，每次的对接焊缝选取不同的焊接参数。焊接参 数包括焊接电流、电压、焊接速度、激光功率，通过固定两个参数，变动一个参数的 方式对 Q235 钢进行激光复合对接焊。由于焊缝组织状态决定焊缝的性能，故本课题 采用金相显微镜拍摄不同参数时的焊缝微观组织，根据图片对比发现各参数对于焊接 所形成的焊缝组织的影响。同时用显微硬度计来测量焊缝、母材和热影响区硬度，分 析出硬度变化，从而反映出组织均匀的参数。

研究结果表明，对于 Q235 低碳钢的激光-MIG 复合焊焊接参数的最佳焊接电流 为 200A，焊接速度为 20mm/s，激光功率为 2kW。在此参数下焊缝宏观形貌、微观 组织、硬度分布均较为合理。同时在分析过程中也很清楚的看出各参数对于焊缝宏观 和微观的各种影响。

毕业论文关键字：Q235低碳钢；激光-GMAW 复合焊；宏观形状；微观组织

Abstract Welding technology plays a vital role in the field of modern industrial and welding the renewal and development of the technology of modern industrial development has great role in promoting, in automotive, aerospace, shipbuilding and other fields of welding technology is also more and more high。 With the development of science and technology, laser MIG hybrid welding as two welding methods of collection, which combines the advantages of electric arc welding and laser welding, welding characteristics with very good, this welding method is worthy of exploration and research。

This topic selects the Q235 steel as the research object, the use of H08Mn2SiA wire, using laser hybrid welding welding method to test plate butt welding, butt welding of each selected different welding parameters。 Welding parameters such as welding current, voltage, welding speed, laser power, through two parameter is fixed, change a parameter on the surface of Q235 steel by laser hybrid welding。 Due to the weld microstructure state determining weld performance, so this topic using metallographic microscopy images with different parameters of the microstructure of the weld, according to contrast images found effect of each parameter for the welding of weld microstructure At the same time, the hardness of the weld, the base material and the heat affected zone were measured by micro hardness tester, and the hardness variation was analyzed, which reflected the uniform parameters of the tissue。

Research results show that, for low carbon steel Q235 in laser MIG hybrid welding welding parameters of the best welding current of 200A, welding speed 20mm / s, laser power 2kW。 under the parameters of weld macro morphology, microstructure, hardness distribution are more reasonable。 At the same time in the analysis process is also very clear that the parameters for the various effects of macro and micro weld。

Key words: Q235 low carbon steel; laser -GMAW hybrid welding; macroscopic shape; microstructure

目 录

第一章 绪论 1

1。1  引言 1

1。1。2  激光电弧复合焊原理及特点 2

1。1。3 激光-电弧复焊的分类 3

1。2 激光-MIG 复合焊研究现状