Research On Laser Welding Process Parameters Of 6061-T6 Heavy Plate Aluminum Alloy

High power laser welding process of medium and heavy plate aluminum alloy is extremely unstable,which is easy to produce defects such as weld collapse and pore,which seriously affects the mechanical properties of weld.Therefore,it is very important to optimize the process parameters,study the forming law of weld,determine the appropriate shape characteristic parameters,establish the classification criterion of weld shape,improve the welding conditions and control the welding defects for high power laser welding of medium and thick aluminum alloy sheets.Firstly,the effect of process parameters on high power laser welding of medium and heavy plate aluminum alloy was studied,and the optimum process parameters were determined.Simufact welding is used to simulate and analyze the welding process,and the range of process parameters of single factor welding experiment is preliminarily determined,which can provide guidance for subsequent laser welding experiment.Then,according to the results of numerical simulation,the welding characteristics and the optimum process parameters of 6061-T6 aluminum alloy with 6 mm thickness were determined.Then the penetration weld of 6mm thick 6061-T6 aluminum alloy laser welding was studied,and the classification standard of penetration weld was established.Using shape factor H2/(H1+H2+H3)and W3/W1,penetration welds are divided into nail welds,wedge welds and cup welds.The quantitative relationship between process parameters and weld shape was studied.The metallographic structure of welds with different shapes was analyzed.The relationship between weld shape and grain size and shape was studied.The mechanical properties of joints with different weld shapes were tested.The influence of process parameters on weld shape,mechanical properties and metallographic structure of 6061-T6 aluminium alloy under penetration weld was determined.In order to improve the weld defect,the welding experiment was carried out by changing the welding angle of the test plate during laser welding,and the effect of welding angle on high power laser welding of medium and heavy plate aluminum alloy was studied.Simufact welding is used to predict the temperature field distribution and pool shape of angle weld.Based on the simulation results,single factor angle welding experiments,porosity experiments and mechanical properties tests are carried out to study the porosity defects and mechanical properties of angle weld.According to the results of the classification study of penetration weld,angle factors are added to re-conduct welding experiments and study the welding angle.The effect of degree on classification of penetration welds.The experimental results show that changing the welding angle can improve the pore defect of the weld and improve the mechanical properties of the weld.After the angle parameter is added,the shape of the weld still conforms to the relationship between the shape factor and the process parameters,and the classification rule of the weld is still valid.