Finite Element Simulation And Experiment Research On Rolling Process Of AZ31 Magnesium Alloy Plate

At present,with the growing consumption of energy and the aggravating of environmental,the demand of environment-friendly materials is particularly urgent.As a new type of structural material,magnesium alloy has excellent comprehensive performance,which has a wide application space in many fields.Magnesium alloy plate is basically obtained by rolling process.But,the difficulty in plastic deformation of magnesium alloy has limited its production and application at normal temperature.However,magnesium alloys has good plastic deformation ability during hot rolling process,so it is very significant to explore the hot rolling process of magnesium alloy.In this paper,the influence of different parameters on the distribution of temperature field,equivalent stress field,equivalent strain field and rolling force during the hot rolling of AZ31 magnesium alloy was investigated by finite element simulation,then combined with the rolling experimental including surface quality analysis,microstructural analysis and tensile test to optimize the magnesium alloy rolling process.The main contents of this paper are as follows:The Deform-3D numerical simulation software was used to establish the single pass rolling geometric model of magnesium alloy.The simulation results shows that the equivalent stress decreases with the increase of rolling temperature,decreases with the increase of rolling speed,increases firstly and then decreases with the increase of reduction rate.The equivalent strain increases with the increase of reduction rate,the equivalent strain is seldom influenced by the selected interval of the rolling temperature and the rolling speed.Along the thickness direction,the temperature field shows ladder-like distribution,the temperature of the plate increases from the surface to the center,and the temperature of the plate increases with the increase of reduction rate and rolling speed.The rolling force increases with the increase of reduction rate,decreases with the increase of rolling temperature.Through comprehensive analysis,the rolling parameters of magnesium alloy plate were optimized.The multi-pass hot rolling geometric model of magnesium alloy plate was established by Deform-3D software.During multi-pass rolling process of magnesium alloy after single annealing,the equivalent strain increases with the increase of rolling passes,the equivalent stress of the last rolling pass was the largest,the rolling force increases firstly and then decreases with the increase of rolling pass.During multi-pass rolling process of magnesium alloy after twice annealing,the equivalent stress,the equivalent strain and the rolling force of the last two rolling pass were all decreased compared with multi-pass rolling process of magnesium alloy after single annealing.The surface quality,microstructure and mechanical properties of magnesium alloy plates after multi-pass rolling were studied.Surface cracks appeared on the multi-pass hot rolled plates of magnesium alloy after single annealing.The surface of the multi-pass hot rolled plates of magnesium alloy after twice annealing was smooth,with less edge cracking.The microstructure of the multi-pass hot rolled plates of magnesium alloy after twice annealing was equiaxed grain.After annealing treatment,the maximum tensile strength was 245 MPa,the maximum yield strength was 154 MPa,and the elongation was 19%.The transverse and longitudinal mechanical properties of plate were basically the same,and the anisotropy of the plate was small.