Numerical Simulation And Experimental Research On Laser-MIG Hybrid Welding Of Medium And Thick Aluminum Alloy Plates

Laser welding technology is an advanced processing technology with fast welding speed,relatively concentrated heat source,small thermal deformation of the base material during processing,high degree of automation,high precision processing,and is widely used in various fields.However,at the same time,it also has many problems.In order to further expand the application range of laser welding and get rid of the limitation of high gap requirements,laser arc hybrid welding has appeared.The laser arc hybrid welding technology combines the advantages of laser welding and arc welding to achieve a synergistic effect of 1+1>2.Compared with traditional welding methods,the heat input is small,the deformation is small,and there is no need for processing after welding.To a certain extent,it improves the welding efficiency and plays an important role in improving the quality of the weld.In addition,the quality of the weld is mainly determined by the weld surface shape,microstructure and mechanical properties.Therefore,the welding process parameters are optimized to obtain the welded joint under the best process parameters.Laser-MIG composite The application of welding engineering is of great significance.In this paper,the basic process research of laser-MIG hybrid welding of 6082 aluminum alloy with a thickness of 10 mm is carried out.First,combined with the research content,a finite element analysis model of the temperature field and stress field of laser-MIG hybrid welding of 6082 aluminum alloy plate is established.,Then use the finite element analysis model to expand the parameterized research,change the laser power,welding speed and other parameters respectively,and study the influence of different parameters on the temperature field and stress deformation of laser-MIG hybrid welding.Then,a 6 kW high-power fiber laser was used to conduct experimental research on the welding process of 10 mm thick aluminum alloy,and it was concluded that different welding process parameters(laser power,welding speed,defocusing amount,wire feeding speed)have a positive effect on the surface morphology and The internal forming influence of the weld,and finally the microstructure,microhardness,and tensile strength are studied according to the optimal parameters.The research content is as follows:(1)Adopt the combined volume heat source simulation program,establish a three-dimensional geometric model,simulate and analyze the temperature field and stress field of laser-MIG hybrid welding 6082 aluminum alloy thick plate under different welding process parameters(laser power,welding speed).The results show that the laser power has a greater impact on the penetration depth of the molten pool;speed up the welding speed and obtain a stable temperature field and deformation field,indicating that laser-MIG hybrid welding can achieve high-speed welding.(2)Based on the laser arc hybrid welding method,analyze the weld seam after welding.When the laser power is 4.0 kW,the weld seam is the best.When the welding speed increases from 0.9 m/min to 1.5 m/min,the quality of the upper surface of the weld is gradually improved.Different defocus amounts have a greater impact on the weld width.(3)The microstructure and material tensile strength of the weld joint of 6082 aluminum alloy medium and thick plates based on laser-MIG hybrid welding were tested and analyzed,and compared with the base material.The weld fusion zone,heat-affected zone and the structure of the base metal are obviously different,and the heat-affected zone is narrow.The weld fusion zone of laser-MIG hybrid welding is mainly equiaxed dendrites with small grain sizes and different shapes.The heat-affected zone of laser-MIG welded joints has the highest microhardness,with an average hardness of 96.5 HV.Compared with the base material and the heat-affected zone,due to the influence of the filler wire,the maximum hardness of the fusion zone appears.The average tensile strength of the weld of laser-MIG hybrid welding is 258MPa.The tensile strength of laser-MIG welded joints can reach 77%of that of the matrix,and due to the large number of pores,the tensile fracture positions of laser-MIG composite welded specimens are all in the weld..