Research On Hot Stamping Process Of 6061/Q345 Composite Panels

The increase in car ownership has brought challenges to green and environmentally friendly development requirements.Improve the vehicle lightweight technology,effectively reduce energy consumption and improve vehicle safety performance is the core of automotive manufacturing competitiveness.Traditional steel as the representative of the automotive materials in the development of lightweight vehicles have the problem of large amount usage of the precious metals and easy to corrode.Aluminum and aluminum alloy as the representative of the lightweight vehicles have the problem of poor strength,high cost of developing advanced materials and poor forming characteristics at room temperature;the metal composite materials have the problem of weak forming characteristics at room temperature and easy to crack and the carbon fiber composites are expensive.In this paper,based on the technology of hot stamping,integrated the advantages in strength,stiffness and corrosion resistance of Steel-Aluminum Alloy laminated metal composite panels,the forming process of hot stamping of 6061/Q345 double-layer metal composite panels was analyzed by finite element simulation theoretical analysis and experimental research.The Gleeble-3500 thermal simulation testing machine was used to test the rheological behavior of each component at different temperature and strain rate.The higher the initial temperature and the smaller the rate,and then the smaller the flow stress.These also provide data for the establishment of hot stamping finite element thermodynamic coupling model of the laminated metal composite panels.The structure of the steel B-pillar was simplified and the geometrical model and laminated metal composite panels model of steel-aluminum alloy laminated metal composite U-shaped material were established.Based on DYNAFORM and LS-PREPOST finite element software,firstly the grid model and material model of the U-shaped laminated metal composite panels simlified by B-pillar were established.Then,the contact models between the mold and panels were established and the heat transfer and motion control parameters and boundary conditions were set up.And then complete the establishment of finite element model of hot stamping of the U-shaped laminated metal composite panels of 6061/Q345.Based on finite element solver of LS-DYNA,firstly,the influence regular pattern of the temperature field,stress field,thickness and the stamping force in the forming process were studied.And then the effects of initial temperature,stamping speed,mold gap,die radius and hardening time on the forming effect were studied.Finally,a comprehensive analysis shows that the bestparameters of the composite plate U-shaped material studied at this paper was the initial temperature of 550 ℃,a punching speed of 36.75 mm / s,a mold gap of 3.0mm,a die radius of11.5mm and a holding time of more than 7s.That provided a theoretical analysis reference for the choice of the process parameters.The hot stamping test scheme of the U-shaped composite plate with respect to the initial temperature,the holding time,the stamping speed and the hardening time was developed.The correctness of the finite element results was verified between the springback angle and the thickness of the part and the simulated value.Tensile and bending experiments were carried out to explore the influence of various factors on the mechanical properties of the forming parts.The experimental results show that the initial temperature is 550 ℃,the pressing speed is 36.75 mm / s,the holding time is 10 min,the mold gap is 3.0mm,die radius of 11.5mm,hardening time is 7s the most appropriate conditions.