Research On Open-type Inverted Extrusion Forming Method For Inner Hole Of Hollow Shaft

The hollow shaft is one of the most common parts in the mechanical industry, whichis widely used in automobile、motorcycle、energy exploration and other fields. At present,the processing method of the kind of parts was often used plastic forming, it could not onlyimprove the utilization ratio of material and mechanical properties of parts, ensurecontinuous metal flow line, but also could meet the requirement of mass production. Theopen-type inverted extrusion forming for inner hole of hollow shaft is one of the plasticforming methods. Compared with the close-type inverted extrusion, it could significantlyreduce the forming force. However, because of the influence of many factors, theextrusion-parts was appeared easily process defects such as scraping and upsettinginstability when the process of open-type inverted extrusion. Thus, it is the key foropen-type inverted extrusion forming for inner hole of hollow shaft that how to draft areasonable forming scheme to avoid producing process defects, reduce the forming forceand increase die’s service life.This paper is based on geological drill joint as the research object, according to thestructural characteristics of the part, the two different kinds of forming processscheme,which were the open-type inverted extrusion forming of hollow billet and thecomposite extrusion forming of solid billet, were made. Using the rigid-plastic finiteelement analysis software DEFORM-3D, the finite element model was established, thenthrough the numerical simulation analysis and comparison of the two kinds of formingscheme, it shows that the superiority of the open-type inverted extrusion forming of hollowbillet. Through researching the open-type inverted extrusion forming for inner hole ofhollow shaft of metal forming characteristics, the influence law of process parameters onmetal forming was obtained. With the method of orthogonal experimental design tooptimize process parameters of the open-type inverted extrusion forming for inner hole ofhollow shaft, the optimum process parameters were determined.On the basis of the above research results, and according to the condition of existingequipment, the process test for open-type inverted extrusion forming for inner hole ofhollow shaft was carried out. The test results show that the optimized process parameterscould effectively decrease the forming force, form a good quality specimen, meet thedesign requirements of extrusion part, and verify the authenticity of the simulation results.