| Hexagon hollow parts is a new kind of fasteners with a different structure, it has a bettermechanics and mechanical properties and lighter weight than conventional solidfasteners,therefore，it has broad application prospects and demand for space. Actually,manufacture such parts with hexagon hollow hole as allotype hole parts, machining methodsexists consumables, low efficiency, low-intensity defective; Process sucu as roll extrusion,spinning, cross wedge rolling and radial forging needing complicated process and requiringhigh processing equipment; Cold extrusion process is an efficiently, low consumption andsimple equipment requirements, excellent product quality with less machining methods.Therefore, study of cold extrusion technology for high strength hexagon hollow parts not onlyhas important theoretical significance, but also has great economic benefits.According to the characteristics and examine requirements of the extrusion parts, basedon the comprehensive analysis of the multi-pass extrusion solutions, composite extrusionsolutions and cold extrusion forming solutaions, using a hollow tube with cold extrusionforming process to forge high-strength hexagon hollow parts was Determined. At the sametime, through theoretical analysis, established the hollow billet extrusion pressure model inthe extrusion process and the velocity model of the billet plastic deformation zone boundaryparticles. By using numerical simulation software Deform-3D, the low of Extrusionpressure,strain and metal flow in Extrusion process was analyzed,meanwhile, relationship ofthe maximum force and mold forming key parameters also analyzed by simulation results,and possible defects in the extrusion forming process was successfully predicted. Useingsingle factor method, studied the die cone angle α,corner radius R and the length of workingband L to the influence of maximum extrusion pressure, determined the appropriate die coneangle range of60to65°,suitbale corner radius is1.5mm,and the proper working band rangeof3to4mm. Finally, by the results of theoretical analysis and numerical simulation, extrusion die wasdesigned and cold extrusion of trial was completed. The results shows out: the surfaceaccuracy and hexagonal hole size of the extrusion parts all reached inspection requirements,and,numerical simulation was basically the same to the experimental results. Simultaneously,the results also verified the feasibility of the process and the reasonable of the mold design. |
