Study On Weld Seam Surface Quality Of CO₂ Laser Welding 5083 Aluminum Alloys For Shipbuilding

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.