Research On Cross Wedge Rolling Process Based On Square Billet

With the development and popularization of cross wedge rolling technology,the requirements for the billets are becoming wider and wider.Relying on the traditional round billets alone will limit the popularization of cross wedge rolling technology,especially for some large parts such as railway axle,it is difficult to obtain such a large round bar.Therefore,it is of great practical significance to study the cross wedge rolling process based on square billet.The cross wedge rolling of square billets is a breakthrough in the selection of raw materials in the traditional cross wedge rolling process.In addition to the end recesses and microstructure inhomogeneity,the mechanical properties and surface quality of rolled pieces are affected by the shape of billets.In this paper,the cross wedge rolling of square billet is studied in various aspects,and the characteristics of square billet rolling are revealed,so as to improve the comprehensive quality of rolled pieces and realize the near net forming of parts.In order to systematically study the forming mechanism of square section billet rolling and the distribution law of stress and strain field of cross section and longitudinal section in the process of rolling broadening.This paper adopts deform-3 D finite element simulation software establishes the finite element model of square section billet,tracks the stress and strain of the workpiece center,and studies the rolling of square billet and round billet through comparison method;In order to explore the influence rule of process parameters on the quality of shaft end,the single factor analysis method and orthogonal test are designed respectively,and the influence of process parameters on the quality of shaft end is obtained in the rolling process of square billet and round billet;In order to further obtain the rolled piece with small end concave center and flat end face,a chock was added to the die and the influence of process parameters and chock parameters on the quality of the shaft end was studied;In order to study the uniformity of the microstructure of the rolled piece,the change rule of the temperature field and the distribution feature of the microstructure were analyzed in the forming process based on the cross wedge rolling of square billet.Finally,through rolling experiments and metallographic experiment and square billet rolling process were carried out to verify the correctness of the simulation results.In this paper,the rolling forming mechanism of square billet has been proved,which makes the application of square billet in the field of cross wedge rolling possible,and also provides reference for the research of other key technologies of cross wedge rolling of square billet,which is conducive to the development of cross wedge rolling of non-circular section billet in China.