Cold Extrusion Process For Involute Spline Part And Concave Die Optimize Design Based On Numerical Simulation

At present, cold extrusion shaping process is among the best process of thenet shaping in material forming processes. The process is high accuracy, stablequantity and very suitable for production in bulk. With the development of theautomobile, especially the car, it is required that higher performance, lower cost,the less consumes. The adopting cold extrusion shaping process makes net shapethe important and complicated car parts are the development trend of theautomobile manufacturing industry nowadays. Another advantage of coldextrusion shaping process lies in products themselves, especially surface and asubsurface of the parts can keep the cold-harden appearance. Its residual pressurestress of the surface not only can raise the hardness and strengths of the materials,but also can raise fatigue life of the parts.In this paper, We chose the finite element numerical simulation withelastic-plastic model with study object, which the MSC/SuperForm wassuccessfully applied to simulate the cold extrusion forming process of involutespline for transmission shaft. The parameters of process, diameter of steel billet,entrance half angle and working land of die were been analyzed. According to theresults of the former, the cold extrusion tests were carried out and get bestextrusion part. The experimental results indicate that the numerical simulationtechnique is an efficient method to obtain the composite extrusion formingparameters. And based on these, compared assembled concave die with integerdie on extrusion process influence, combined tradition in advance assembledconcave die computer method, optimize some best of all parameters, including toinside and outside diameter of concave die and interference and so on. Mostlyresearch work of the paper as follows:⑴ Theory base of establishing model and the cold extrusion processprinciple of the car part: three dimension big distortion elastic-plastic mechanics,elastic mechanics.Emphases on introducing three dimensions elastic-plastic mechanics and thefinite element basic theories, and the their applied characteristics in metal bulkprocess. Carried through describing object geometry compose,physics relationand border value question when producing big distortion. Based on principle ofvirtual work, established big distortion elastic-plastic finite element model,basicequation and asking aresolution arrange formula . Based on flow theory, took outconstitutive relation of elastic-plastic material.⑵ Key technology problem.The numerical simulation process exist below 5 field key technology problem:geometry description of die cavity, contact analysis including boundary condition,contact algorithm and contact definition and so on, material model, meshregeneration and friction model etc. For different problem type, the resolvent ofthese key technologies is different. So we must be use given analysis in givensituation, the paper with example explains the resolution method of keytechnology, which have been referred in spline extrusion.⑶ With certain spline shaft as a case, simulated cold extrusion process withMSC.SuperForm software, and obtained perfect spline tooth shape. Viz. look fromits integer, fibre series on spline, and metal fibre figure and spline structure figureinosculate each other, model cavity of concave die tooth shape can favoringaccomplished metal fill, wholly tooth shape except for its extremity, satiation andflatness, full of fillet, it is very velvet the transition between tooth root fillet andtooth side, nought lack for example collape. Researched the metal flow rule andtooth shape fill rule of spline shaft during cold extrusion process, numericalanalyzed extrusion part the change of extrusion part deforming griddingdistributing,stress strain field quantity.⑷ Optimized combination concave die.The concave die entrance half-angle and the diameter belt size et al. wereoptimized design by a series of analogue result combined the combinationconcave die computational method and the value simulation method, separately.And the combination concave die thickness, excessively full quantity value et al.were optimized on the basis of the traditional combination concave diecomputational method. Finally, each optimized design parameter of the concavedie structure had achieved, and obtained the anticipated result.[5] Research of quenching and tempering 40Cr material model.Through compress experiment measure the flow stress of quenching andtempering 40Cr material at room temperature, protract reality stress-strain curve,build flow ossify model, and import it into intelligent analysis system, not onlyimprove the authenticity and veracity of numerical simulation, but also extend thematerial storeroom of MSC.SuperForm software and MSC.Marc software, forsubsequent user create convenience condition.In conclusion, the paper not only is more thorough and development of coldextrusion process optimization, but also is more optimized of model structurebased on tradition stress assembled concave die computer method. And this hassome instruct meaning of practice production. The paper exist many defects, awaitmore thorough discuss and research in the future.