Study On Temperature Field And Tissue Properties Of Hot Stamping And Forming Of 22MnB5 Variable Thickness High Strength Steel Plate

With the development of technology,cars are slowly penetrating into every household,bringing travel convenience and environmental problems one after another.Research shows that 75% of the oil consumption of the car is to overcome its own weight,so due to the need for energy saving and environmental protection,the concept of automotive lightweighting was born.Of course,lightweight is not simply to simplify the car model,but to ensure the original strength and safety performance of the premise,as far as possible to reduce the overall mass of the vehicle.For example,traditional high-strength parts are often designed with material thickness and strength selected based on maximum load,thus resulting in excess material thickness and strength properties in non-maximum load areas.Therefore,this paper introduces 22 MnB5 high-strength variable thickness plate(TRB)to achieve the matching between structure and load bearing through reasonable changes in thickness and mechanical properties to maximize the service potential of the structure under the premise of light weight,so the following studies are conducted in this paper:(1)A finite element model for hot stamping and forming of 22 MnB5 high-strength TRB plate was established,and the hot stamping simulation of 22 MnB5 high-strength TRB plate with different initial conditions(changing stamping speed,die temperature,and die rounding)was carried out to analyze the temperature field distribution in different thickness regions,and based on the demand of performance gradient distribution of high-strength parts in real life,the model was simulated with zonal cooling heat treatment to reasonably regulate the cooling rate in thin,transition,and thick regions of TRB plate to achieve the performance gradient distribution of TRB plate.(2)The microstructure evolution mechanism of 22 MnB5 high-strength boron steel plate after heat treatment process under different parameters was investigated by metallographic organization observation,scanning electron microscope observation,grain size,electron back diffraction observation and tensile fracture analysis.(3)The trends of yield strength,tensile strength,elongation and Vickers hardness of22 MnB5 high-strength boron steel plate after heat treatment process under different parameters were obtained through room temperature one-way tensile test and Vickers hardness test,and the distribution forms and evolution laws of mechanical properties of22 MnB5 high-strength boron steel plate after heat treatment process with different parameters were systematically studied.This paper is based on the study of the mechanical properties and microstructure mechanism of 22 MnB5 under different heat treatment processes,combined with hot stamping and cooling simulation of 22 MnB5 high-strength TRB plate,to provide theoretical guidance for the realization of ultra-high strength parts lightweight.