Research And Simulation Of Stamping Of Tailor Welded Blanks Of Advanced High Strength Duap Phase Steel

The application of advanced high strength dual phase steel TWB on the automotive body manufacturing area is an effective method to achieve energy conservation and sustainable development.Advanced high strength dual phase steel is applied to the automobile industry successfully for its excellent mechanical performance and corrosion resistance. However the requirements of the equipment and process is more stringent when forming complex and heavily deformed parts. Tailor welded blanks can give full play to the performance of the material, and decrease equipment costs. And tailor welded blanks become another important development direction of the automobile lightweight. On the other hand, the thickness and the material properties diversities of base materials and the weld seam make the tailor welded blanks forming process more complicated. Numerical simulation applied more and more in designing and manufacturing in order to improve the products structure and forming process. However, the difference between weld seam and base materials makes it even harder to build an appropriate FEM model.In this paper, advanced high strength dual phase steel is taken as the research object, and tailor welded blanks technology and stamping process were combined together in this paper to systematically study the impact which the finite element model of weld seam had to the numerical simulation and the impact which the process parameters had to the forming properties by means of FEM as well as physical experiments. Then the simulation results and experiments were compared to get an accurate method of building finite element model of weld seam and to optimize the process parameters. The main research results of this paper are showed as follows:(1) Two kinds of tensile specimens of different materials, heterogeneous and thickness-equal tailor welded blank tensile specimens with longitudinal weld seam, specimens with horizontal seam and specimens with o45 seam were studied mechanical properties by tension experiments. And the microstructure and microhardness of the specimens was studied to discover the micro reason of the macro properties.(2) An equivalent finite element model of weld seam were proposed and compared with the simple finite element model of weld seam, and applied to the simulation of drawing process of tailor welded blank box. The result of strain and stress of the blank、movement of weld seam、thickness and punch force were analyzed to discuss the influence that the weld seam FEM model has on the simulation results. Finally, we compared the simulation results with the experiments and found that the results simulated by equivalent weld seam model fitted more to the physics experiments. And the key process parameters of stamping of tailor welded blanks were analysed and optimized.