Simulation And Fabrication Research Of Laser Hot Wire Welding Of 7075 Aluminum Alloy

High strength aluminum alloy is widely used in aerospace,transportation,high-end equipment and other fields.With the rapid development of high technology,its requirements for them will be increasingly high.Safety and environmental protection and energy conservation have become the most important development direction.The 7 high-strength aluminum alloy has become the most promising lightweight material with its excellent comprehensive performance,and has been the common concern of domestic and foreign scholars and experts.In this paper,1.5mm7075 high-strength aluminum alloy sheet is used as the base material,and welding wire is 1.2mm 7075 aluminum alloy.The laser hot wire welding model is established by Fluent software to study the effect of different temperatures of wire on weld formation when feeding into the molten pool,and it will be verify by test.First,the wire temperature test will be carried out to investigate the relationship between the different wire feed speeds and the hot wire current on the temperature of the heated wire.Then the orthogonal process test of laser welding was designed to study the influence of welding parameters on the weld forming of laser welding.After further optimization,a set of test parameters can be obtained for good weld formation.In addition,the experiment of laser welding with scandium element will carry out under the optimal technological parameters,and the rule of influence of scandium element on the weld formation and welding quality of laser welding was studied.Meanwhile,laser self-fusion welding was set as a control test.The specific research content of this paper includes the following aspects:1)Establish the heat flow coupled laser heat wire welding model of cone heat source and surface heat source.The cone heat source is used to melt the parent material and the surface heat source is used to melt the welding wire.The influence of different temperature welding wire on weld formation is studied by setting welding wire feeding at different temperature.By optimizing the process parameters,a set of parameters can be obtained for good weld formation.2)During laser welding,welding wire fusion mainly relies on the combined action of hot wire current and laser energy.In order to study the temperature when the welding wire is put into the melting pool,the temperature measurement test of the welding wire is carried out.The temperature of the wire when the wire is sent into the molten pool is obtained by the temperature of the wire under different current and different wire feeding speed through the infrared thermometer.3)The influence of hot wire current,laser power,wire feeding speed,welding speed and butt clearance on laser hot wire welding process is studied by designing orthogonal process test of laser hot wire welding and adopting standard orthogonaltable L16(54).By optimizing the parameters,a group of optimal process parameters can be obtained to obtain good weld formation and welding quality.4)Laser thermal wire welding under optimized parameters was carried out for the experiment of laser thermal wire welding with the addition of scandium.Meanwhile,laser self-fusion welding was set as the control group.The results of the three groups of welding were tested,including the weld morphology,metallographic structure,element composition,hardness and tensile strength.Based on the test results,the effect of scandium on the weld formation and welding quality of laser thermal wire welding is analyzed.