Study On Rolling Deformation Process Of AZ61 Magnesium Alloy Packed By Stainless Steel Tube

As the lightest structural metal material,magnesium alloy has excellent properties such as high specific strength,specific stiffness,and damping,and is known as "green engineering material of the 21 st century".The application of magnesium alloy is mainly concentrated in automotive,aerospace,electronic products,and other fields.Although its application scope is wide,the total amount of use is far less than that of steel and aluminum.The inherent hexagonal closed-packed crystal structure of magnesium is the main reason limiting its application.Magnesium alloy sheet as the basic raw material of secondary forming,the research and development of reasonable and efficient magnesium alloy sheet manufacturing process is increasingly prominent.At present,the manufacturing process of magnesium alloy sheet is still complicated,which is difficult to meet the huge demand in the foreseeable future.Therefore,the research on the manufacturing process of magnesium alloy sheet plays an important role in promoting the development and upgrading of magnesium alloy manufacturing industry,and is of great significance to the sustainable development of China's national economy.In this paper,a magnesium alloy rolling process with stainless steel as pack material is proposed.There is only one pass in the whole process,and the reduction can reach 50%.The strong restriction from stainless steel tube provides multi-directional compressive stress,which limits the edge crack phenomenon of magnesium alloy material in the rolling process to the maximum extent.This experiment with AZ61 magnesium alloy and 304 stainless steel tube as the experimental material,using the commercial finite element software Abaqus explicit module are simulated and the feasibility of the process parameters optimization is studied,finally the simulation results are verified by means of experiment,and the microstructure and mechanical properties of magnesium alloy sheet is studied.The main research contents and conclusions are as follows:(1)The pack rolling model was established,and the directly pack rolling and closed pack rolling processes were analyzed by orthogonal test method and response surface method.The results show that the higher the temperature is,the smaller the average rolling force is,the easier the rolling process is,and the better the magnesium alloy sheet forming effect is.The selection of rolling reduction is closely related to the peak stress and average rolling force of magnesium alloy sheet,and the suitable rolling reduction should be selected according to the actual situation.(2)By means of numerical simulation and experiment,the defects in magnesium alloy forming process were verified and the process parameters were optimized,and the optimal wall thickness parameters were obtained.(3)Based on finite element simulation results under different rolling temperature of pack AZ61 magnesium alloy rolling experiment,through the tensile test,optical microscope and electron back scattering diffraction technology has carried on the observation and analysis to sheet,the results show that the sheets by directly pack rolling and closed pack rolling under the two kinds of experimental course of various performance trends are similar.When the rolling temperature is 400?,the grain size of AZ61 magnesium alloy is about 5 ?m and the texture strength is the lowest.In terms of mechanical properties,the yield strength tensile strength and elongation reach 213 MPa,305 MPa and 23.1%,respectively.