Papers by Keyword: Cross Wedge Rolling (CWR)

Abstract: Cross wedge rolling hollow shafts with a mandrel has attracted much attention in the recent years because of the demand for light components. Finite element method was used to simulate the rolling process of hollow part and validated by experiment. By tracking strain change of the typical points and analyzing the strain contour maps of cross-section at four typical moments, the cause of cross section oval and shaft shoulder protuberance of part is expounded.

Abstract: Multi-wedge Cross Wedge Rolling (MCWR) is an advanced technology in forming long axial parts, and it does not have the disadvantages of Single-wedge Cross Wedge Rolling (SCWR).However, it is extremely important to realize the regularity of the displacement on the end-section of the rolled parts in MCWR due to the complexity of its forming mechanism. In this paper, based on the method of the displacement on the end-section of the rolled parts in SCWR, the rules of the displacement on the end-section of a typical rolled part in MCWR were investigated theoretically, and the curve on the end -section of the rolled part in MCWR were analyzed.Based on the curve, the regularity of metal flowing and the characteristic of forming for the typical rolled part in each phase by MCWR were analyzed. It is of high value in studying the forming mechanism and designing mould and technics in MCWR.

Abstract: When forming automobile semi-axle using Multi-wedges Cross-Wedge Rolling (MCWR), it is difficult to avoid the rolling bending phenomenon. Thus to improve the product quality for finding out the causes and preventing rolling bending is essential. In this paper, the finite element model(FEM) analysis software Deform-3D was used to analize the bending causes, and giving the corresponding measures from numerical simulation of the forming of multi-wedge automobile semi-axle using Cross-Wedge Rolling. Based on the corresponding simulation experiments, the results indicate that the seasures is feasible. The results of this study for rolling forming of automobile semi-axle can improve product quality and provide a theoretical basis.

Abstract: Finite element model of Cross wedge rolling asymmetric shaft is established, contrasting with symmetrical rolling, the axial relative displacement of weak-side and strong-side’s metal in asymmetric cross wedge rolling is analyzed. The results show that: axial relative displacement asymmetrical rolling on the weak-side undergo the process of “increase-decrease-unchangeableness” and axial non-uniform deformation increases; axial relative displacements on the strong-side undergo the process of “decrease- unchangeableness” and axial non-uniform deformation decreases. The results provide a theoretical basis for the cross wedge rolling asymmetric shaft parts.

Abstract: The rolling process of the three-roll cross wedge rolling with non-uniform temperature field was simulated with the finite element method (FEM). The distribution of the temperature and equivalent strain in radial section of rolled pieces was analyzed. The microstructures and properties of different positions in radial section were investigated. The results indicate that the temperature field and equivalent strain are ring-likely distributing in the radial section of rolled pieces. There are high temperature and small strain in the center. The temperature decreases and the strain increase gradually from the center to surface. The microstructures and properties of rolled pieces are different in different positions. The microstructure in the center consists of pearlite and proeutectoid ferrite, while the surface consists of cementite particles and fine ferrite.

Abstract: This paper investigates a three-dimensional finite element model for the cross-wedge rolling process has been used to characterize the workpiece material stress and deformation behavior. Considering the characteristic of cross wedge rolling, the static implicit FEM program is selected. To simulate all forming stages in the cross wedge rolling process, dynamic adaptive remeshing technology was applied. Examples of numerical simulation for strain, stress distributions and rolling load components have been included. The stress distributions in the cross-section of the forming workpiece are analyzed to interpret fracture or rarefaction at the center of workpiece. The computer codes in finite element method can be used for a large variety of problems by simply changing the input data.

Abstract: Problems with gear shaft formed by cross wedge rolling (CWR), such as slip, disorder of tooth, material deficiency at two sides of the gear, have restricted the application of this craft to form gear shafts. In this paper, numerical simulation on the process of gear shaft formed by cross wedge rolling was carried out with the help of solidworks and deform 3d. Compared with the standard profile, there is margin on the profile of the gear shaft for further process. It’s proved that the traditional methods to make a gear shaft can be replaced by CWR. From curves of force in three directions, it is easy to conclude that radical force and tangential force are the main forces which are exerted on the dies and vary similarly in all stages.

Abstract: Since internal defects in the cross wedge rolling (CWR) process can weaken the integrity of the final product, it is necessary to investigate the influence of tool parameters (forming angle α, spreading angle β and area reduction Ψ) on central deformation of workpiece.The change law of average maximum principle stress of central point of workpiece has been studied to optimize the tool parameters to avoid the emergence of void. It is found that workpiece with better quality can be formed under the condition of =30°, β=8°, Ψ₁=48.6%,and Ψ₂=53.3% . Subsequently, a blank for the connecting rod was produced without central defects in factory, which verified the feasibility of study results.

Abstract: To produce preforms for complex long flat parts with an unsteady mass distribution along the longitudinal axis rolling processes, like cross wedge rolling, can be used. Tools for cross wedge rolling processes can be constructed as roller or flat, both with wedges. In the collaborative research project SFB 489 “Process chain for the production of precision forged high performance parts” the subproject “Innovative machine and tool technology for precision forging” deals with the development of a flashless forging process for a two cylinder crankshaft with pin and flange. This process is developed by IPH – Institut für Integrierte Produktion Hannover. The first preform of the developed forging sequence is produced by a cross wedge rolling process on the basis of flat with wedges. To consider the mass distribution of the two cylinder crankshaft in the preform for a rolling process four mass concentrations for the crank arms and mass concentrations for pin and flange are needed.

Abstract: With widely use of aluminum alloy in the cares and other industry fields and the like, the aluminum alloy workpieces are becoming the important components, such as load bearing and so on, in which it has been gradually paid attention to the formation and the producing roughcast of shaft forging part of aluminum alloy. the process of across wedge rolling for wrought aluminum alloy has gradually taken notice of improving production rate and saving metal in this field because of its advantages and superiorities. It is very necessary to research and analyze the flow regularity and forming characteristic of aluminum alloy. In this paper, the forming process of cross wedge rolling for wrought aluminum alloy is simulated with Deform 6.0 soft. Thus, it is analyzed that features about cross wedge rolling for aluminum alloy and changeable characteristic of stress in the central axis and changeable regular of effective stress in wedging stage and stretching stage . At the same time, it is researched that the flow characteristic of aluminum alloy from outer layer to central axis. The results as following: in the forming process of cross wedge rolling for aluminum alloy, the central portion of workpiece is applied by two pairs of tensile stress and one pair of compression stress. The flowing velocity of aluminum alloy is gradually reducing from outer layer to center portion along workpiece’s axis. Keywords: Cross Wedge Rolling, Wrought Aluminum alloy, Stress, Numerical simulation