| In order to obtain the excellent performance of AZ80 magnesium alloy thick wall(wall thickness more than 10mm pipe),the technology of back extrusion forming is deeply explored and studied.First,according to the poor deformation capacity of AZ80 magnesium alloy,the thickness of the forming pipe wall is 22mm,and the deformation of the tube wall is uneven during backward extrusion,a new structure of the backward extrusion die is designed,and the size of the blank is determined.According to the material properties of AZ80 magnesium alloy,the parameters of the back extrusion process are determined.Secondly,the use of DEFORM simulation software for the mold in the backward extrusion process under different process parameters were simulated.The simulation results show that:The strain of the reverse extrusion process decreases from the inner and outer walls of the tube to the central position of the tube wall,and the deformation is inhomogeneous;The inhomogeneity increases with the decrease of the extrusion temperature and the increase of the extrusion speed.;When the extrusion speed is too fast,the pipe can easily cause damage.Third,the experimental research on the reverse extrusion process of AZ80 magnesium alloy thick wall tube is carried out.The experiment found that under the extrusion speed of lmm/s,the thick wall pipe with good surface quality can be extruded and extruded at the extrusion temperature of 290?320?350 and 400?.Finally,the tensile test of the forming tubes under different extrusion parameters was carried out.The results show that the mechanical properties of each part of the pipe are non-uniform,and the mechanical performance of the pipe wall is better than the center position of the tube wall,while the transverse mechanical performance is slightly lower than the longitudinal mechanical property.At the extrusion temperature of 400 ?,under the extrusion speed of 1mm/s,the mechanical properties of the pipe are the best. |
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