Papers by Keyword: Cross Wedge Rolling (CWR)

Abstract: This paper investigates the interfacial slip between the forming tool and workpiece in a relatively new metal forming process, cross-wedge rolling. Based on the finite elements method, three-dimensional mechanical model of cross wedge rolling process has been developed. Examples of numerical simulation for strain, stress distributions and rolling load components have been included. The main advantages of the finite element method are: the capability of obtaining detailed solutions of the mechanics in a deforming body, namely, stresses, shapes, strains or contact pressure distributions; and the computer codes, can be used for a large variety of problems by simply changing the input data.

Abstract: Rolled-piece end quality is one of key factors to decide material utilization ratio in cross wedge rolling (CWR). Good workpiece end quality can improve material utilization ratio effectively. In the paper, by adding the block wedge near the end of mould, it can block surface metal which flows faster in the axial direction and avoid the end concavity of rolled piece. The material loss will not be present and good end quality rolled piece will be produced. The results are significant for improving material utilization ratio and promoting applications of CWR.

Abstract: Cross wedge rolling of asymmetric shaft parts has a series of problems such as the difficulty of forming, and the rules of mental flow are not clear until now. Rigid plastic FE models of the asymmetric rolling and symmetric rolling were adopted to analyze the difference of the stress and strain fields of cross section and vertical section in the two rolling processes, which illuminated the rules of the stress and strain fields in the asymmetric rolling process. The research of the stress and strain fields in asymmetric rolling has positive significance for recognizing the forming characteristics and predicting deformation defects in asymmetric rolling process.

Abstract: The paper investigates a process of cross wedged rolling (CWR) for manufacturing thick-walled hollow axles. A finite element numerical model coupled deformation and heat transfer of CWR is established using commercial finite element software DEFORM-3D. The rolling process of hollow axle during CWR is simulated successfully. The stress, strain and temperature distributions of workpiece are obtained and analyzed. The simulation results show that forming thick-walled hollow axles through CWR is feasible.

Abstract: Because of unbalanced axial force of cross wedge rolling asymmetric shaft-parts causing the rolling play and not stably, it is key factors to restrict application in asymmetric shaft-parts of cross wedge rolling. Axial force balance depends on technical parameters. So the influence regularities of axial force to technical parameters is researched in this paper by Ansys-Ls/Dyna finite element software. Finite element model is authenticated by experiment of rolling force, and the influence regularities of axial force of cross wedge rolling asymmetric shaft-parts is get. It will provide a theoretical basis for choosing reasonable parameters in mold design of cross wedge rolling asymmetric shaft-parts.

Abstract: End concavity controlled effectively is one of important factors to achieve no material loss end of workpiece in cross wedge rolling (CWR). In the paper, nonlinear finite element modeling(FEM) for the process of CWR is presented with the aid of DEFORM software. The production mechanism of concavity on the end of rolled-piece is analyzed by displacement method, grid method and axial strain method. The reason of concavity is obtained that the surface metal flows faster than the center and the metal deformation in axle is uneven. The study is significant to avoid end concavity and realize no material loss end for rolled-piece.

Abstract: Cross wedge rolling valve roughcast is charactered by minor diameter, long stretching and heavy section shrinkage; however, it is hard to select a set of suitable machining process parameter and prone to rolling internal defect. In order to research this problem, a whole forming process of valve roughcast by single cross wedge rolling is simulated with finite element simulation software DEFORM-3D 6.0, which focuses on the stress and strain of the center point of rolled piece under different forming angles. The rolling experiment under different forming angles was done on H500 rolling mill to calculate and analysis of the areas of the centre holes for each rolled piece. The influence of forming angle on internal defect is discovered by a method combining finite element simulation and experiments. At last, it is concluded that forming angle of 28°can improve the internal defect of valve roughcast formed by single cross wedge rolling.

Abstract: The metal microstructure of a product formed by cross wedge rolling (CWR) has much effect on the comprehensive properties of the final product. The microstructure model of GH4169 alloy was programmed into the rigid-plastic finite element software DEFORM-3D by the secondary development in this paper, so the microstructure evolution during the CWR process can be simulated. The finite element model (FEM) that coupled deformation, heat transfer and microstructure evolution was established. Based on the model, the evolution of microstructure of GH4169 alloy in the process of CWR was realized with the simulation. The strain, strain rate, temperature and the distribution of grain size of the part were obtained in the whole process of CWR. The simulation results show that the dynamic recrystallization is the main grain refinement mechanism for the CWR process and the grain refining effect of the workpiece during the CWR process is remarkably.

Abstract: Based on the rigid-plastic deformation finite element method and the heat transfer theories, the forming process of cross wedge rolling was simulated with the finite element software DEFORM-3D. The temperature field of the rolled piece during the forming process was analyzed. The results show that the temperature gradient in the outer of the work-piece is sometimes very large and temperature near the contact deformation zone is the lowest while temperature near the center of the rolled-piece keeps relatively stable and even rises slightly. Research results provide a basis for further study on metal flow and accurate shaping of work-piece during cross wedge rolling.

Abstract: Finite element numerical simulation, Cold-rolled AL1100, Cross wedge rolling Abstract. The geometrical and physical models of a ladder shaft for finite element numerical simulation are developed. With the ANSYS/LS-DYNA software, the knifing zone, forming zone and sizing zone of the cold-rolled AL1100 ladder shaft are simulated, including the flow of the material and the strain condition in the whole rolling process. Distribution of tangential strain , radial strain , axial strain , and equivalent strain is analyzed. The influences of wedge corner , stretch corner and reduction of area on the strain and rolling force are discussed. The study is helpful to reveal the law of metal flow inside the rolled part and guide the production of cold Cross Wedge Rolling (CWR).