| The thin-wall extruded tube of magnesium alloy AZ31 is selected as research object in this paper. The influence of the structure of the mold and the process parameters on the extrusion course is discussed and influence of extrusion ratio on the mechanical properties of tube and microstructure is also analyzed.According to analyses the different extrusion forming methods, the forming method of isothermal forward extrusion full lubrication is defined with hot deformation behaviors of magnesium alloy.The extrusion course of thin-wall extruded tube of magnesium alloy is simulated by using the numerical simulation of finite element method (FEM). The cone angle, extrusion temperature, extruding velocity, friction conditions and extrusion ratio are discussed which impact equivalent stress, equivalent strain and extrusion force and determining the reasonable process parameters and the structure of the mold. The simulation results show that the relatively small extrusion force, reasonable distribution of equivalent strain and equivalent stress can be get when the cone angle 45°, extrusion temperature 380℃, extruding velocity 0.1 mm/s and friction coefficient 0.1, which benefit forming.The forming process of thin-wall extruded tube of magnesium alloy is established based on analyzing the results of numerical simulation and designing mould. Emphasis is put on the control of wall thickness difference in designing the structure of the mold.Based on above research, the tube with precise size, low roughness and little wall thickness difference is received during the trial - manufacture of the thin-wall extruded tube of magnesium alloy AZ31. Testing analyzing properties and microstructure, the result show that the tube has impact microstructure and strong bearing capability and the tensile strength and elongation improve obviously.The correctness of numerical simulation and physics experiment and feasibility of the thin-wall extruded tube of magnesium alloy forming by this process are verified.
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