Search Results

You are looking at 1 - 5 of 5 items for

  • Author: B. Bacroix x
Clear All Modify Search
Open access

S. Wroński, K. Wierzbanowski, M. Wroński and B. Bacroix

Abstract

The results of three-dimensional simulation of asymmetric rolling, using Finite Elements Method, are presented. The example case of low carbon steel is considered. The rolling asymmetry, considered in the present work, results from different angular velocities of two identical working rolls. The effects of asymmetry on stress and strain distributions, material bending and variations of normal force and torque exerted by rolls are calculated and discussed. A special emphasis is done on the influence of inclined entry of a rolled material, which can appear in sequential rolling. Such the entry can partly compensate the material bending during. The results of the present simulations show that optimum parameters can be found in order to minimize the effect of sheet curvature and to reduce the applied torque and normal rolling force.

The predicted internal stress distributions were applied next in the crystallographic deformation model; the predicted textures of symmetric and asymmetric rolling are in good agreement with experimental results.

Open access

A. Halloumi, Ch. Desrayaud, B. Bacroix, E. Rauch and F. Montheillet

A Simple Analytical Model of Asymmetric Rolling

An original analytical method is proposed for modeling asymmetric rolling (ASR) of metal sheet. It is based on a uniform strain field depending on a single optimization parameter, viz. the entry velocity of the sheet. The shear and normal strains associated with an ASR pass are derived analytically. Moreover, it is shown that the entry velocity almost coincides with the outer linear velocity of the slower roll, as far as ASR is sufficiently asymmetric. In that case, closed form formulae are available for the main rolling parameters such as the overall power dissipated and the two rolling torques. These results can be straighforwardly used for practical applications.

Open access

M. Wronski, K. Wierzbanowski, S. Wronski, B. Bacroix and P. Lipinski

Abstract

The goal of this work was theoretical and experimental study of micro- and macroscopic mechanical fields of 6061 aluminum alloy induced by the asymmetric rolling process. Two-scale constitutive law was used by implementing an elasto-plastic self-consistent scheme into the Finite Element code (ABAQUS/Explicit). The model was applied to study the asymmetric rolling. Such a deformation process induces heterogeneous mechanical fields that were reproduced by the model thanks to the crystallographic nature of constitutive law used. The studied material was processed, at room temperature, in one rolling pass to 36% reduction. The resulting material modifications were compared with predictions of the two-scale model. Namely, the calculated textures were compared with experimental ones determined by X-ray diffraction. Especially, detailed quantitative analysis of texture variation across the sample thickness was done. The influence of this texture variation on plastic anisotropy was studied. The advantages of asymmetric rolling process over symmetric one were identified. The main benefits are a nearly homogeneous crystallographic texture, reduced rolling normal forces and homogenization of plastic anisotropy through the sample thickness.

Open access

K. Wierzbanowski, M. Wroński, A. Baczmański, B. Bacroix, P. Lipinski and A. Lodini

Problem of Lattice Rotation Due to Plastic Deformation. Example of Rolling of f.c.c Materials

Rotations of grain crystal lattice are responsible for texture formation during plastic deformation. The classical definition of lattice rotation leads in some cases to different texture predictions than the definition based on the orientation preservation of selected sample directions and/or planes. For example, if classical <110>{111} slip is taken into account for f.c.c. materials, the former approach enables to predict both copper and brass types of rolling texture, while classical approach predicts only the first one. The analysis of rolling process was done for two types of lattice rotation and in function of grain-matrix interaction parameter used in a deformation model. Correlation factors estimating the similarity of predicted and experimental textures as well as the shares of ideal orientations are discussed.

Open access

A. Uniwersał, M. Wróbel, S. Wroński, I. Kalemba-Rec, M. Wroński, K. Wierzbanowski, A. Baczmański and B. Bacroix

Abstract

In the most recent years the asymmetric rolling (AR) attracts attention of researchers and technologists. This process can improve some technological parameters (e.g. modification of rolling torque and load, power requirements, etc.) as well as provide the possibility of grain refinement in a relatively inexpensive way. Most of the reports concerning microstructural changes produced by AR refer to high deformations imposed in highly asymmetric conditions. However, such rolling conditions are difficult to control, so there are no prospects to their quick industrial implementation. The present paper refers to relatively low deformation and low asymmetry rate, that is much more interesting for the industry. It was shown that bending of the rolled band (important disadvantage of the AR technology) can be controlled by adjusting of the amount of deformation and asymmetry. It was also shown that ca. 30% reduction in thickness during cold rolling, together with a relatively low asymmetry, reduces significantly the grain size and produces a more fragmented microstructure inside grains of the polycrystalline copper comparing to the symmetric rolling (SR). The material hardness after AR is higher than after the SR. Moreover, the crystallographic texture asymmetry, expressed by its rotation around the transverse direction, is observed in the AR material.