【作者】 牛振；

【导师】 张冬云；

【作者基本信息】 北京工业大学 ， 光学， 2008， 硕士

【摘要】 在全球交通工具向轻型化发展的背景下,铝合金在造船工业中得到了越来越广泛的应用,铝合金焊接在生产中常采用熔化极氩弧焊的方法,面临的主要问题是焊接速度慢、焊后变形大、接头性能差等,进而影响了船舶制造的质量和效率。在船舶制造中采用激光焊接可以提高生产效率、减小变形,提高焊缝性能和船舶制造质量。造船工业中使用较多的是5083铝合金,但是激光焊接过程稳定性差、深熔焊时焊缝成形较差、表面容易出现孔洞等问题成为5083铝合金焊接的难点。本文主要针对5083铝合金的焊缝成形问题进行研究,首先对船用5083铝合金激光焊接工艺参数进行试验,分析了影响5083铝合金激光焊接焊缝成形的主要因素,找出了激光功率和焊接速度、辅助气体、离焦量、光束聚焦对焊缝成形的影响规律。然后对激光焊接工艺参数对焊缝成形的影响规律进行了理论分析,对5083铝合金激光焊接焊缝成形较差的原因进行了分析,进而从小孔、熔池的受力方面对焊接过程中产生孔洞的原因进行分析。文章对几种主要缺陷的产生原因进行了分析,并提出了改善焊缝成形的方案。基于上述研究结果,文章最后对5083铝合金进行了长焊缝的激光对接焊试验,找出了优化的焊接工艺参数,并进行了金相试验、显微硬度试验和力学性能试验(如拉伸试验、弯曲试验)。研究成果有助于进一步了解铝合金激光焊接过程中激光与材料相互作用及所发生的物理现象,有助于进一步提高激光焊接过程的稳定性、提高铝合金激光焊接质量,从而提高我国铝合金高速船舶制造业水平,同时对车辆、航空航天等行业的铝合金焊接技术具有重要的指导意义。更多还原

【Abstract】 Under the background of the global light–duty trend of transport facility aluminum alloys have been applied widely in the shipbuilding industry more and more. In the manufacturing process of production, MIG is often used for welding of aluminum alloys. There are some problems that have effect on the quality and efficiency of the ship building, such as slower weld speed, bigger deformation and inferior joint performance. The Application of laser welding in shipbuilding can increase the production efficiency, reduce weld deformation and improve weld performance and ship building quality. However the instability of laser welding process, bad surface of weld seam, blowholes on the surface are the primary difficulties by the application of the 5083 aluminum alloy laser welding for ship building.This thesis aimed at the surface quality of laser weld seam of 5083 aluminum alloy. Firstly, a lot of experiments for technology parameters of laser welding of 5083 aluminum alloy have been made. Then the paper analyses the main factor which has effect on the laser welding seam quality, find the effects of the laser power, weld speed, auxiliary gas, defocusing distance and beam focused degree on the quality of the weld seam surface.Secondly, the thesis analyses abstractly the effect of laser welding parameters on the surface quality of weld seam and the possible reasons of the poor weld seam according to the keyhole and pressure of welding pool. Furthermore the investigations under improvement of surface quality of weld seam have been made.Based on the results mentioned above, the laser jointing experiments of long weld seams of 5083 aluminum alloy have been made using optimized weld parameters, and then some experiments such as metallographic test, micro-hardness test, mechanical properties of tensile and bending have been made.The research results contribute to understanding the interaction between laser beam and materials and related physical phenomena during weld progress. The study helps to improve the stability of process of laser welding and the quality of laser weld seam, what will enhance manufacturing level of high-speed ship and has an important guiding significance to the aluminum laser welding technology confronted with vehicles, aerospace industries.更多还原