Analyses Of Welding Procedure&Deformation And Development Of Double Beam Laser Welding Actuator Of T-shape Joint For Aluminum-lithium Alloy

This article take the fuselage panel T-joint as the research object,design and processing for dual beam laser welding robot welding process welding executive mechanism and auxiliary welding fixture,Welding executive mechanism can realize the accurate adjust of gas transport and wire feeding,adjustable range of 0-30mm,It also can adjust the three-dimensional direction of the aspirated and wire feeder,adjust the range of 0°and 90°,wire feeding and gas transport device located in the weld pool in front and back,The position of the rolling device is reserved in the design,and the welding executive mechanism is suitable for the double beam laser welding of the T type joints of the non plane and complex curved fuselage panels.The angle of the laser incident angle is adjusted to 20°-90°,including laser system、wire feeding system、gas transport system、monitoring system、weld seam tracking rolling system.The fixture moves with the welding process,using two pairs of rolling wheel symmetrical lateral compressing stringers on both sides,a pair of positive pressure wheel stringers surface,directly combined with the robot arm are welding parts positioning and rigid fixation,simplify completely fixed fixture installation cumbersome operation,implementation of the welding parts is flexible to fixed,effective control of welding deformation and production efficiency.The double beam laser welding process of 1.5mm thick 2A97-T3 Al-Li alloy without filler wire T type joint was studied.Analyzes the effects of laser power and welding speed on the forming of T type weld,welding defects,stress and deformation and microstructure and properties.The results show that the laser power and welding speed affect the welding quality in the way of heat input,when the heat input is higher and lower,obtained good weld.Considering the penetration depth,the optimum parameters are P=1200W and v=2.5m/min,The T-joint consists of a matrix organization,heat affected zone and melting zone,melting zone has fine crystal and columnar crystal,The microhardness curve of skin stringer to roughly U distribution,The highest hardness of base metal,is about 120 HV_0.1,The melting zone elements was burning,evaporation,coupled with stomatal defects resulting in the decrease in hardness,apparent softening hardness of about 75 HV_0.1。Using finite element software ABAQUS to establish three-dimensional model of2A97-T3 aluminum lithium alloy T joint temperature and stress deformation process,the welding thermal cycle and the variation law of stress and deformation field were analyzed.The results show that the heat conduction effect of two skins and stringers,welding heating and cooling speed is obviously large,high temperature region is very small,because the welding fixture is rigidly fixed,the welding deformation is very small,and the simulation results are consistent with the deformation of the process test results,and the angular deformation occurs.the results of the longitudinal residual stress simulation are compared with the actual measurement results under the optimum process parameters,and verified the validity results of the simulation.