Numerical Simulation Research On The Process Of Cooling Forming Of Hot Stamping For High Strength Steel Sheet

With the gradually strengthening of global energy saving and environmental protection,more and more people pay much attention to the safety of vehicles, the application of highstrength steel lightweight design and manufacture of the car are put in the first place by motorcorporations. Ultra high strength steel is an important effective methods for weight reduction andpromoting security. The hot stamping is a kind of advanced manufacturing technology to thestamping forming of high strength steel plate. Domestic and foreign scholars are on the systemresearch about the hot stamping of high strength steel plate in recent years, which includes: thepreparation of high strength steel and ultra high strength steel, hot stamping system design, theresearch of microstructure and phase field model and the numerical simulation of hot stampingprocess. And the key problem is the numerical simulation of hot stamping process.In this paper, the way of combining theoretical analysis, numerical simulation andexperimental validation is used to research on the hot stamping quenching forming process ofhigh-strength steel22MnB5.The main works are as follows:1) The finite element model is built through setting material properties and boundaryconditions, and the temperature distribution analysis of parts and mould is completed by ANSYSMechanical/LS-DYNAand LS971solver.2) Based on temperature field simulation, austenite decomposition model is established bythe numerical simulation analysis of high tensile steel plate for the cooling rate, thermal radiation,heat convection and heat conduction in hot stamping die quenching process, through theANSYS/LS-DYNA, austenite decomposition son phase (ferrite, pearlite, bainite and martensite)weight percentage, the vickers hardness and yield strength of parts can output, finally themicrostructure and mechanical properties of hot stamping pieces are obtained;3) The hot stamping experiment of U-shaped part is completed to verify the optimized result,which is done on a hydraulic press (Y32-100). The hot stamping mould consists of punch, punchretainer, die and punch motherboard.22MnB5steel sheet is chosen as the experimental material.During the punching, the process of temperature of four nodes on the midsections are measuredwith thermo-couple detector (K). The microstructure of U-shaped part is measured withmicro-scope after the experiment. by comparing the experimental results and the simulationresults, The result shows the reliability of the simulation results.