The Research Of Electroplastic Induced Magnesium Plate Asymmetrical Accumulative Rolling Technology

Because of the unique advantages on the material properties of rolling, Magnesium alloys have a wide application range. Each single magnesium alloy rolling technology all has its advantages rely on their own strengthening mechanism. Although they can obtain fine crystal structure and have the strength to be able to compete with high alloying alloy without add any alloy elements. But the problems are also obviously and can not be ignored. Such as there are serious anisotropy with rolling plate. The preparation technology is not mature enough. The mechanical performance of rolling plate is still need to further improve. Based on this, this article is combining with electrical plastic processing, asymmetrical rolling and accumulative rolling technology innovatively. And we have a study on the key technology of electrically induced asymmetrical accumulative synergy rolling. The research is continue to explore a new method of gaining the materials with high performance fine grain and make up for the disadvantages of traditional rolling technology that need multi pass and have to arrangement heat treatment between two passes. The new method is increasing deformation, and at the same time reducing the crack, and this greatly improved the production efficiency and the quality.This article explores the plastic deformation theory of electrically induced magnesium plate asymmetrical accumulative composite rolling. We contrast analysis the unit rolling pressure of this composite rolling with the methods of T. Karaman and E. Orowan, respectively, and got the average unit rolling pressure formula using in this model. We are analyzed the factors that influence the flow stress behavior of electrically induced magnesium plate asymmetrical accumulative composite rolling. The factors were induction electrical parameters, asynchronous ratio, rolling layers etc.. And we are built the rheological mathematical model under the condition of the composite rolling state.We have a design of experiment for electrically induced magnesium plate asymmetrical accumulative composite rolling process that was influenced by multiple factors affecting. The electrically induced plastic effect of the finite element model can be divided into two parts, thermal effect and electric excitation effect, respectively. Calculate the heat generated by the current through electrically thermal effect analysis in ANSYS Multiphysics. And gain the mechanical parameters of electric excitation conditions through electrically induced tensile test. Then the above parameters are introduced to the LS-DYNA directly implementing the composite rolling process coupling simulation with temperature field and mechanical field, electric field.By changing the asymmetrical ratio of up and down rolls in the rolling process, to explore the influence of asymmetrical ratio to the deformation behaviors of the composite rolling. Research shows that: as the rolls speed difference there is a shear stress effect in plank up and down. These caused plank crystals were rotated, and accelerate the occurrence of the dislocation movement. But too much asymmetrical ratio will result in plank slipped, and the effect no longer obvious. So the rheological stress in the process of rolling was increasing after first decreases with the increase of the asymmetrical ratio. The rolling temperature was decreasing after first increases with the increase of the asymmetrical ratio. And get smallest rheological stress when asymmetrical ratio 1.15.By changing the pulse current and pulse frequency in the rolling process, to explore the influence of electric parameters to the deformation behaviors of the composite rolling. Results show that: the influence of electric parameters on the one hand performance in thermal effect, on the other hand performance in electric excitation effect. These two aspects all have weaken on rheological stress of rolling process. Rheological stress decreases with the increase of pulse current and increasing after first decreases with the increase of pulse frequency. And get smaller values in pulse frequency 275 Hz and pulse current 245 A. When the pulse frequency is too high(400 Hz), its electric excitation function on the plate is no longer obvious, and the influence on rheological stress only performance in thermal effect.By changing the rolling layers of the rolling process, explore rolling layer effect on the deformation behaviors of the composite rolling. Results show that: the accumulative rolling through the plate laminated rolling increase plastic deformation, and make the plate in a short period of time produces more heat. Plate temperature rise faster, weakened the deformation resistance, and rheological stress decreases. But its influence is not as big as asymmetrical ratio or electric parameters.Based on composite simulation results, and through multiple linear regression analysis by R statistical software, build the rheological mathematical model under the electrically induced magnesium plate asymmetrical accumulative composite rolling process. Considering similar theory of metal plastic deformation of electrically induced asynchronous accumulation composite rolling process and electrically induced tensile test. This study was carried out by electrically induced magnesium plate tensile test, and verified the composite rolling simulation results. Through the Matlab software to graphical displayed the composite rolling mathematic model and evaluation mathematical model fitting compared with electrically induced tensile test results. The results show that the rheological mathematical model can better reflect the magnesium plate plastic deformation regular under different pulse current, pulse frequency.