Research And Numerical Simulation Analysis Of Aluminum Alloy Forming Process

With the progress of the society,human's awareness of environmental protection,fuel vehicle emissions on the environment pollution has been the general concern of all countries,the world's major automobile manufacturing enterprises are actively doing layout of the new energy vehicles,and lightweight vehicle has important significance for new energy vehicles.Compared with steel materials,aluminum alloy has the advantages of light weight,good plasticity,high specific stiffness and high specific strength.With the continuous progress of aluminum alloy processing technology,the use of aluminum alloy parts in automotive parts will be more and more.Aluminum alloy control arm is one of the most important parts in vehicle suspension system.It plays the role of guiding and transmitting force in suspension system,and has high requirement for stiffness,strength and service life.At present,forging technology is adopted in the forming of aluminum alloy control arm.Because of the narrow forging temperature range and the anisotropy of extruded aluminum alloy during forging,there are many defects in the forging process,such as folding,dissatisfaction,disorderly flow,coarse grain and so on.These defects will seriously reduce the strength of the forgings and affect the service life of the parts.In this paper,the CATIA drawing software and Deform numerical simulation software are used to simulate the isothermal forging process of the material for the 6082 aluminum alloy control arm.The bending process of aluminum alloy thick plate has been studied theoretically and experimentally.The main research contents and results are as follows:1.According to the structural characteristics of the control arm,the process flow of blanking,heating,rolling for blank,bending,forging,cutting,trimming and heat treatment is designed.The die design and calculation are carried out for roll forging,bending and die forging.2.Through the finite element simulation analysis of the roll forging process,the structure of the roll forging die is optimized,so that defects such as bending,overlap and indentation can be avoided during roll forging process.The bending and forging process is simulated and analyzed,and the structure and size of the roll forging are optimized.The design of the bending and forging dies is improved so as to ensure the processing of qualified forgings.3.The simulation analysis of velocity field,temperature field and stress and strain field is carried out for the forming process.The analysis shows that during the whole roll forging process,the streamline formed by the metal flow inside the billet is consistent with the axis direction of the roll forging,and the distribution is uniform,without interweaving and disorder.The holding end and the small head are kept at 480? at the heating temperature.The deformation of the middle rod is the largest and the maximum temperature reaches 527?.During die forging,the stress of the billet is much higher than that of the other parts due to the excess billet flowing out of the bridge side of the flash groove.The maximum stress is 46 MPa.The maximum load of the die forging is about 4800 KN.4.The grain size of the roll forging and die forging process are simulated and analysed.The results are as follows:(1)in the process of roll forging for billet,changes in grain shape occur: interaction of the roll forging die pressure and heat,in large size grain boundary nucleation,and grew into columnar crystal,and then the column crystal grains are transferred to equiaxed grains in the process of deformation.Finally,the refined equiaxed grain is obtained.(2)During the simulation of die forging,the changing trend of the grain shape and size in the internal structure of the blank is consistent with the changing trend of the roll forging process,that is,the original large grain is firstly converted to columnar crystal,then to equiaxial crystal,and the microstructure of the forgings is refined,and the mechanical properties of the forgings are improved.5.The present situation and treatment method of the indentation on the outer surface of the aluminum alloy thick plate in bending forming,and the limitation of the existing technology in solving the bending indentation of the sheet material are introduced.The influence factors of producing indentation are discussed.A new solution is put forward and a detailed feasibility analysis is carried out.On the basis of theoretical analysis,a half axle turnover die without bending is developed which can be applied to thick plate and large radius corner bending parts.Through practical application,it is proved that the mould of this new structure is very effective,completely eliminating the indentation on the surface of thick plate bending parts,and improving the surface quality of the bending parts.