Study On Spinning Forming Of Magnesium Cylindrical Component

As an advanced plastic forming process near the end, spinning technology has been widely used in process forming of the rotational symmetric parts, however, it has not yet started in the application of magnesium alloys. In this dissertation, the spinning process of cylindrical component of AZ81 magnesium alloy is researched exploringly, which will provide reference on the development of the methods of plastic forming of magnesium alloy.In this paper, combining two advantages of production process of casting and plastic deformation, a new production line that plastic deforming directly from the preformed casting billet is proposed; The DEFORM-3D software is applied to carry out the elastic-plastic finite element numerical simulation in the spinning process of the magnesium alloy cylindrical component, and the experiment is verified. Simulation capability of simulated reality to the actual process is evaluated. Finally, the changes of microstructure and performance of magnesium alloy in the spinning process are researched and observed systematically, which will provide evidence for the digitization of spinning process design and microstructure-property prediction.The results are as follows:①The distribution regularity of equivalent stress, strain and spinning force in the spinning forming process are obtained by simulating. Effect of spinning temperature and feed rate on the equivalent stress and spinning force is analyzed. The results are useful to optimize the process effectively, shorten the research cycle. The stress and strain reach the maximum in the contact area of spinning wheel and workpiece. The radial spinning force is much greater than axial force and tangential force, and the size is first increased and then decreased.②After taking different combinations of the process parameters to simulate, a set of optimal process parameters for forming is got finally. Spinning temperature and feed rate of spinning wheel are the important factors to magnesium alloy spinning forming. The temperature around 350℃is suitable for plastic deformation of magnesium alloy, the appropriate feed rate(0.75mm/r)can guarantee a good surface quality of workpiece, influence law of the various process parameters on the final quality of the part is revealed.③After spinning experiment, through observing microstructure of AZ81 magnesium alloy in different spinning pass, and according to the extent of grain refinement and size of cracks, the spinning forming mechanism is understood, and effect of different process parameters on the spinning forming process is analyzed. With the spinning pass increasing, the equivalent stress, strain and spinning force of workpiece are also on the rise.④According to the results, the generation mechanism of wrinkling and crack in spinning process are analyzed. Material defects, rough conditions, equipment capability and process parameters are important reasons for spinning defects. Meanwhile, the corresponding preventive measures are given by combining the simulation results.The simulation results that are verified by spinning experiment show that the generation of various defects is avoided in spinning process as a result of the reasonable spinning process parameters. Optimizing the design of spinning die and forming process parameters can ensure the forming properties of magnesium alloy and achieve the expected goal.