Numerical Simulation And Process Parameter Optimization Of Hot Stamping Forming Of 22MnB5 High Strength Steel

With the development and progress of society,people put forward higher requirements for travel modes,and the demand for cars is growing.The development of the automobile industry is becoming more and more prosperous.However,the accompanying problems are increasing energy consumption and the intensification of environmental pollution,and the contradiction between the two is becoming more and more prominent.From the perspective of automobile production,reducing body weight is one of the important measures to solve the contradiction between them.Taking the car as an example,25% of its whole vehicle weight is in the body weight.Therefore,the selection of lightweight materials in the body manufacturing process is very necessary to reduce energy consumption and exhaust emissions.In the selection of lightweight materials,taking effective strengthening measures can improve the strength of steel,in order to achieve lightweight and meet the original mechanical property requirements.The strength of high-strength boron alloy steel plate at room temperature is 500 ? 600 MPa.However,after the sheet is uniformly austenitized by high-temperature heating,and then after a series of processes such as stamping forming,quenching,cooling and pressure maintaining,the tensile strength of the stamping part can reach 1500 MPa.Due to the complex hot stamping process of high-strength steel,the forming quality of formed parts is not easy to control.If the design and selection of process parameters in the hot stamping process are unreasonable,the hot stamping parts will have defects such as fracture,wrinkling and rebound.In order to avoid or reduce these defects in the actual stamping production process,it is necessary to simulate the hot stamping process of hot formed workpiece,so as to predict the forming quality of workpiece in advance and check whether the hot stamping process design is reasonable.In this way,the research and development time of high-strength steel hot stamping die can be shortened and the production efficiency can be improved.Taking the rear connecting plate of the left sill reinforcing plate of a vehicle as the research object,this paper studies the influence law of the hot stamping process parameters of high-strength steel on the forming quality of its hot stamping parts and optimizes the parameters.The main research contents include:(1)The three-dimensional modeling of the rear connecting plate is carried out by using UG software,and then imported into Auto form software to establish the finite element model of the rear connecting plate.(2)The hot stamping process of the rear connecting plate is preliminarily numerically simulated.The temperature field distribution and strain field distribution of the rear connecting plate parts in the forming process,as well as the thinning rate distribution and springback distribution of the formed rear connecting plate parts are viewed and analyzed.Through the preliminary finite element simulation,it is found that the forming quality of the rear connecting plate needs to be improved.(3)Using the control variable method,the hot stamping process of the rear connecting plate is numerically simulated for many times based on Auto form software.And the variation laws of the maximum principal strain,maximum thinning rate and maximum springback of the formed rear connecting plate are analyzed to study the influence laws of three process parameters: heating temperature,stamping speed and friction coefficient on the forming quality of the rear connecting plate.(4)The three main process parameters of hot stamping forming of the rear connecting plate of the left sill stiffener of a vehicle model are optimized by designing orthogonal experiments,and the test results are analyzed by range analysis method.Through calculation,the optimal level of each factor,the primary and secondary order of the influence of each factor on the test index and the optimal combination level are obtained.The best combination of process parameters is that the heating temperature is900 ? and the stamping speed is 500 mm/s and the friction coefficient is0.43.The hot stamping forming of the rear connecting plate is numerically simulated with the optimal combination of process parameters.And it is found that the formability is good.Finally,the production test of the rear connecting plate is carried out to verify the optimization results.After testing,it meets the production requirements.The process parameters are properly selected.In this paper,the hot stamping process of the rear connecting plate of the left sill reinforcing plate of a vehicle is simulated by finite element method,and the hot stamping process parameters are optimized.The research results provide theoretical guidance for the actual production of rear connecting plate hot stamping parts.It is of great significance to improve the yield of the actual production of the rear connecting plate parts and save the development cost.