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A new study of roll system force relationships in asymmetrical rolling and its influence on rolling process stability

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Progress in Natural Science:Materials International 1995年第6期 80-86页

作者：于九明潘大炜王建国 China Department of Metal Forming Northeastern University Shenyang 110006

The study of roll system force relationships during asymmetrical rolling is of importance in determination of the direction and magnitude of the lateral roll forces directly connecting with the rolling stability, rigidity and loading conditions of a rolling mill. The results obtained by theory and experiment indicate that kinematical asymmetry in strip rolling creates lateral roll forces of significant magnitude depending on the angle of force inclination as affected by roll speed mismatch ratio i, pass reduction ?and the applied strip tensions AT. For optimum mill design and operation, front tension (or tension difference) in asymmetrical rolling should not exceed that required to preserve roll system stability and the appropriate values of i should be no higher than about 1.28 to avoid bearing overloading whilst still retaining in bulk the industrially important roll force reduction effect characteristic of cross shear rolling.

关键词： asymmetrical rolling lateral roll force rolling process stability.

Analysis of Sheet Curvature in asymmetrical Cold rolling

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Journal of Iron and Steel Research International 2013年第5期20卷 34-37页

作者： HAO Liang DI Hong-shuang GONG Dian-yao State Key Laboratory of rolling Technology and Automation Northeastern University

In asymmetric cold rolling, the workpiece is often bent downwards or upwards. A two-dimensional explicit dynamic finite element model with Arbitrary Lagrangian Eulerian （ALE） adaptive meshing technique has been employed to simulate asymmetrical sheet rolling, in which asymmetrical conditions are here due to different roll radii. To validate the simulation, the results of simulation and experiment are compared. Effects of asymmetry due to roll radii mismatch on the normal and shear distributions and on sheet curvature variations are discussed. An optimum roll radii ratio could be found to produce flat sheet. Trials were conducted to investigate the effectiveness of roll radii mismatch as an approach of sheet curvature control.

关键词： asymmetrical rolling finite element method radii ratio sheet curvature

Slab Analysis of Large Cylindrical Shell rolling

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Journal of Iron and Steel Research International 2014年第1期21卷 1-8页

作者： Su-wen CHEN Hong-min LIU Yan PENG Jian-liang SUN National Engineering Research Center for Equipment and Technology of Cold Strip rolling Yanshan University State Key Laboratory of Metastable Materials Science and Technology Yanshan University

Considering the characteristics of large cylindrical shell rolling, such as double driving rolls, asymmetrical rolling and huge workpiece, a slab method was developed to establish the rolling force model. In this model, the non- uniform normal and shear stresses and the upper and lower surface temperatures of the workpiece were taken into ac- count. Moreover, the flow stress model, considering the dynamic recovery and dynamic recrystallization behaviors of the material, was established. The rolling pressure distribution, the rolling force, the rolling torque and the neutral points could be calculated quickly and easily by the roiling force model. The predicted results were shown to be in good agreement with the measured values, which indicated that the model can satisfy the requirement of industrial application.

关键词： large cylindrical shell rolling double driving rolls asymmetrical rolling slab method rolling force

Orientation factor analysis of deformation mechanisms under special processing techniques in AZ31 magnesium alloys

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Acta Metallurgica Sinica(English Letters) 2010年第1期23卷 63-71页

作者： Ping YANG Lina WANG Xiao LI Li MENU School of Materials Science and Engineering University of Science and Technology Beijing Beijing 100083 China Material Department School of Tianjin University of Science and Technology Beijing Tianjin 301830 China

Experiments show that special processing techniques such as asymmetrical rolling （ASR）, equal channel angular pressing （ECAP） and equal channel angular rolling （ECAR） can weaken the basal texture of the magnesium alloys and therefore improve their plasticity. However, the deformation mechanisms related are different. In this paper, we determine the deformation mechanisms activated during ASR, ECAP and ECAR by calculation of orientation factors. Analysis shows that during ASR the shear stress σ13 on the rolling plane of the samples obviously weakens the basal slip and tension twinning that all produce basal texture and improve plasticity due to the promotion of tilt basal texture. During ECAP the shear stress σs on the intersecting plane of two channels promotes tension twinning in the basal oriented grains, whereas under ECAR the shear stress σ13 induced by roller friction on the rolling plane produces the shear stress as on the intersection plane of the two channels that also promotes tension twinning. Although the shear strain is lower in ECAR than in ECAP, the channel clearance in ECAR facilitates tension twinning.

关键词： Magnesium asymmetrical rolling Equal channel angular pressing Equal channel angular rolling Deformation