Research On Energy Saving Optimization Of Hot Stamping Process For ZK60 Magnesium Alloy

Magnesium alloys possess a broad application prospect with many advantages,but it is difficult to form because of its poor plasticity at room temperature.As a result the hot stamping process is applied to improve the plastic ability of magnesium alloy.However forming force is large and the sheet metal requires heating during the hot stamping forming process,which result in high energy consumption and do not meet the current urgent needs for energy-saving and emission-reduction in manufacturing industry.Therefore,the problem of high energy consumption in the process of magnesium alloy stamping has been studied in this paper,and the aim is to reduce the energy consumption of stamping process at the same time to meet the forming quality.First of all,the energy-saving optimization method for stamping process has been proposed to achieve the purpose of reducing the process energy consumption while satisfying the forming quality,taking into account the forming quality and energy consumption in process.The energy consumption indexes including the deformation energy and heating energy consumption are established;According to the characteristics of the stress and strain in the deformation process,the deformation energy is divided into internal tensile deformation,bending and friction energy consumption,then energy consumption of three parts are modeled;Establishing the maximum thickening rate and maximum thinning rate as forming quality evaluation index;And the method of optimization variables establishment,experimental design,experimental treatment and optimization solution are established;and finally the experiments are carried out to verify the results of the optimization.The mechanical properties of ZK60 magnesium alloy under different temperatures and strain rates are studied,and the constitutive equation of ZK60 magnesium alloy is established.Based on the ABAQUS,a numerical analysis model for hot stamping forming is established,taking cylindrical parts as an example,providing theoretical basis for theoretical calculation of energy consumption and numerical simulation analysis.The energy-saving optimization method for stamping process is applied to ZK60hot stamping process.The ranges of the process parameters is determined,and taking the blank holder force,stamping speed and forming temperature as the independent variables of the process parameters,the maximum thinning rate,the maximum thickening rate and the process energy consumption are taken as the evaluation indexes of the energy-saving optimization for ZK60 magnesium alloy stamping process.L₁₆?4³?orthogonal array is selected to establish orthogonal experimental design scheme,and numerical simulation experiments are carried out to obtain the data of forming quality evaluation indexes;The process energy consumption are obtained through theoretical calculation.Based on the two order response surface model,the mapping functions of process parameters and optimization targets are established by least square method.Statistical analysis shows that all the function models were significant.Through the Matlab,based on the NSGA-II algorithm,the multi-objective optimization programming is used to obtain the Pareto frontiers and finally the recommended scheme is given.The hot stamping experiment of ZK60 magnesium alloy tube is designed and verified.The results show that the error is smaller and the accuracy meets the requirement.