| Magnesium alloy sheet rolling is a deformation method that can obtain high strength,better ductility and diversified mechanical properties.It is also the most economical and effective method for large-scale industrial production of magnesium alloy sheets.Therefore,the forming of magnesium alloy sheets after rolling Its industrial application is extremely important.However,various sheet defects are easily caused in the process of magnesium alloy rolling,and there are many factors affecting the quality of sheet forming.At this stage,shape prediction and shape control are the most important modules in the research of magnesium alloy sheet rolling and forming.There are many problems in related research,so it is still an important research direction for the industrial application of magnesium alloy.Based on the theory of sheet rolling and the calculation theory of roll elastic deformation,this paper expounds the application of finite element method in rolling,and according to the actual rolling situation,taking the laboratory two-high mill as a reference,the roll is set to elastic deformation Established an elastoplastic finite element model for AZ31 magnesium alloy sheet rolling.By summarizing and analyzing the simulation results,the law of rolling force changes was obtained,and different rolling process parameters such as reduction rate,sheet width,rolling The influence of speed and rolling temperature on the degree of elastic deformation of the roll,and through nonlinear regression using the least square method,the elastic deflection and flattening deformation model of the roll under different rolling parameters is established.It has been verified that the relevant model has a good fit Goodness;In addition,the influence of various rolling process parameters on the forming of the plate is measured from the vertical and horizontal thickness difference of the magnesium plate after rolling and the size and distribution of the surface residual stress,which provides an accurate judgment on the quality of the plate.A certain analysis basis.In order to verify the accuracy of the elastoplastic finite element model for AZ31 magnesium alloy sheet rolling established in this paper,a laboratory two-high rolling mill was used for rolling experiments,and the measured results were compared with the calculated values of the model.The results are in good agreement.Among them,the main conclusions obtained are as follows:(1)The reduction rate has a greater influence on the elastic deformation of the work roll.The elastic deflection and the amount of flattening of the work roll increase with the reduction rate;in the rolling of different width magnesium plates When,the elastic flattening amount of the work roll is relatively consistent along the axial length of the roll,and the change trend shows a "hat brim" shape;the higher the rolling speed,the greater the roll deformation;the higher the rolling temperature,the smaller the roll deformation.(2)When the reduction rate is different,the longitudinal thickness deviation of the magnesium plate after rolling along the rolling direction fluctuates greatly;the rolling width and the rolling speed have a significant effect on the thickness difference in the vertical and horizontal directions,and the fluctuation range of the thickness difference varies with the width And the speed increases;the rolling temperature has a greater influence on the fluctuation range of the lateral thickness deviation of the magnesium plate after rolling.With the increase of the rolling temperature,the thickness difference between the middle and the edge of the magnesium plate after rolling becomes more and more.The smaller.(3)The residual stress value on the surface of the magnesium sheet after rolling is obviously affected by the rolling speed and temperature.The maximum value of the residual stress decreases with the increase of speed and temperature;the distribution of residual stress increases with the increase of rolling temperature.Become more uniform and stable. |
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