| Light weight materials are widely used in such areas as advanced automobile, aircraft industries and military equipments. Profiles act as the significant structural materials given the predominance of lightweight, recoverable, anti-electromagnetic interference, which AZ31 magnesium alloys could satisfied.the requirement of the aerospace field. While the poor plasticity of magnesium at temperature not get ready for the mass usage of wrought alloy AZ31. Magnesium alloys mainly formed by casting but the trend is plastic processing method. Rotary Stretch Bending technical study is an important research items as well.The article focused on the profile with thin-walled and multi-rib, with the methods of numerical-experimental coupled. The forming process of AZ31 magnesium alloy was investigated. Thermal-mechanical coupled effects on formation quality were discussed, namely the technological parameter such as degrees of pre-stretching, angle of bending and velocity of bending. Main results for this study are as follows:(1) Mechanical state and deformation mechanism of as-extruded AZ31 magnesium sheet in the thermal condition are investigated, state of anisotropic was investigated, the initial texture and deformation mechanism along different direction of as-extruded AZ31 magnesium sheet are obtained:compression twinning dominated the deformation when along to the extrusion direction, tension twinning dominated the deformation when perpendicular to the ED and slipping deformation dominated in between;(2) The stress-strain curves are gained by uniaxial tensile tests. The three-dimensional elasto-plastic thermo-mechanical coupled finite element model of magnesium alloy profile warm tension-rotation bending which based on MSC.Marc is established. The evolution rules of stress field, strain field, temperature field, springback and geometric dimensions of the profile during warm RSB process were analysied. The influence of the result of RSB forming, on process parameters, such as temperature and amount of pretension, was gained. Results indicates that strain value increases with the rising of temperature and the increasing amount of pretension after forming;However, the springback angle makes the opposite changes when compared with strain value. Many factors have a great influence on the springback, which in turn are pretension, bending angle, bending speed and temperature according to the importance;(3) A rotary stretch bending equipment for magnesium alloy profiles is developed, and some warm tension-rotation bending experiments are conducted on it. The effects of forming temperature, bending angle and pre-tension amount on springback angle and geometric accuracy are analyzed. Moreover, the comparison between experimental results and simulation results is conducted.The results show that the simulation results agree well with the experimental results. The effects of process parameters on springback and geometric dimension are coincident Therefore, the simulation results can be used to conduct experiments. The results showed that there are some errors between the experiment and simulation results,but the same change trends are exist among them, which can effectively predict the result of the experiment and indicate the accuracy of the finite element model. So them have referenced value in terms of the experimental prediction. The increasing forming temperature will contribute to improve the forming quality of the profile and decrease the springback,and smallest forming temperature is 140 ℃. When the temperature is in the process of being increased from 140 ℃ to 220 ℃, the springback angle decreases from 5.4°to 3.8°; pretension quantities do the same as forming temperature; when they increases from 0 to 6%, springback angle decreases from 10.9° to 3.1°.
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