The Internal Defects Analysis And Process Optimization Of Transmission Line Shaft In Cross Wedge Rolling

As a new type of shaft parts forming technology,the process of cross-wedge rolling has the advantages of high efficiency,low cost and high product precision.Due to the large batch of the gearbox intermediate shaft,the cross-wedge rolling is the preferred advanced method that is used in intermediate shaft preforming.However, the internal defects in the shaft parts especially as the intermediate shaft with adjacent big disk diameter ration will reduce the strength of rolled piece,destroy the internal organization structure,lead to scrapped parts.In this paper,we study the internal defects of a gearbox intermediate shaft blank that is rolled by the cross-wedge rolling,analysis the internal defects with the aid of finite element simulation,optimize the wedge mold process parameters in order to eliminate the internal defects of the rolled piece.Firstly,the characteristics of the gearbox intermediate which is manufactured by a factiry are analyzed. In order to complete all of the deformation,the thin end part whose percentage reduction of area is big should be rerolled,the internal defects of cross-wedge rolled piece is prone to generate in the rerolled process.The thin end parts that are rolled by cross-wedge rolling in the actual production is easy to appear internal defects.According to the process paraments,the wedge mold is designed to establish the finite element model.The relationship of the internal defects and the transformation law of the effective strain and the max principal stress and so on various fileds in the thin end parts is studied by DEFORM-3D simulation software,ensure the max principal stress as the evaluation of internal defects in the reference field in the period of the first forming wedge wedging.The technological parameters (the Forming Angle, the Broadening Angle, the percentage reduction of area) of the first forming wedge which shapes the thin end parts and the rolling temperature are studied, obtain the relationship of the technological paramenter and the max principal stress by contrast experiment that alters a single process parameter. We think the relationship is the influence of the each technological parameters on the inter defects.According to the influence of the each technological parameters on the inter defects,the internal shaping quality of the thin end parts on the rolled piece is improved by the orthogonal optimization experiment.The factors,levels and optimizing index of the orthogonal experiment are confirmed with considering the mutual influence of process parameters,are uesd in orthogonal experiment to obtain corresponding experimental results. According to the relationship of the optimizing index and various technological parameters and rolling temperature, the fitting function that is established by the Least Square Method could solve the best technological parameters combination.According to the best technological parameters combination, the first first forming wedge mold of the thin end parts is designed again. Establishing the finite element model is to simulate the experiment results in DEFORM-3D. Comparing the actual production in the factory with the simulated results of the best technological parameters combination,is to verify that the reserach achivements of this topic are reliable and feasible.In this paper,the research achievement with the engineering application value will direct the cross-wedge rolling production.