Study On Welded Structure Simulation And Deformation Control Of Thin-Shell Aluminum Cabinet

This paper was aiming at the requirements of lightweight development of vehicles and the welding deformation of "X X" project. The importance and requirement of deformation control of aluminium alloy case were considered, gas metal arc welding method was selected to study on the filling metal, structural design and welding parameters. The relationship of welding process, innerstress and deformation was studied by modern numerical simulation technology, then the scheme how to control and solve the deformation of aluminium alloy welding structure was suggested.The weldability of7A52aluminium alloy was studied on welding methods, filling metals, welding parameters. Semi-automatic MIG welding method was selected to weld7A52aluminium alloy with5356filling metal. Welding conditions of five corner joint were established effectively. Weldcrack was not existed in the weld, which made a good foundation for the welding of simulators.Weld defects such as weldcrack were not found in simulator weld which passed the quality test. Maximum deformation of three bigger plates in simulator1was4.75mm after welding, while maximum deformation of three larger plates in simulator2which was added a support rod before welding was1.15mm after welding. When the support rod was taken off after welding, the value increases to2.98mm which was below the index requirements (3mm/m). The reduction of deformation of plate pieces was attained by using support rod.Through the first round of the finite element numerical simulation, the maximum deformation part was in the middle of the deck1and3. Deck1with maximum deformation (5.997mm) was greater than actual welding. The highest temperature of welding pool decreased from923℃to853℃with the decrease of the depth of transitional fusion drops during simulation process. The whole deformation of case decreased in a certain degree. The maximum value of deformation decreased to4.871mm, which was closed to the actual welding deformation (4.75mm).QC23-B ultrasound impact equipment was used to treat the joint of7A52aluminium alloy. The welded joints with and without UIT treatment were studied by means of weld appearance test, strain and stress test, tensile strength test and so on. The results of the study indicate that the shape of weld toe treated by ultrasonic impact became more smooth, stress in weld toe changed from pulling stress to pressure stress. Tensile strength tests showed that the average tensile strength of the joint treated by ultrasonic impact was271MPa which increased by9.7%compared with the untreated joint, and the treated joints fractured on the weld. It is testified ultrasonic impact treatment changed the stress distribution of weld toe and reduced the stress concentration.