The realization way of snake rolling was introduced. Flow velocity, strain and stress distribution of 7075 aluminum alloy plate during snake rolling and symmetrical rolling were analyzed in Deform 3D. Effects of veloc...The realization way of snake rolling was introduced. Flow velocity, strain and stress distribution of 7075 aluminum alloy plate during snake rolling and symmetrical rolling were analyzed in Deform 3D. Effects of velocity ratio, offset distance between two rolls and pass reduction on the distribution of equivalent strain and shear strain were analyzed. The results show that flow velocity and equivalent strain on the lower layer of the plate are larger than those of the upper layer because of the larger velocity of the lower roll and the gap is increased with the increase of velocity ratio and pass reduction. The shear strain of roiling direction in the center point is almost zero during symmetrical rolling, while it is much larger during snake rolling because of the existence of rub zone. The shear strain is increased with the increase of velocity ratio, offset distance and pass reduction. This additional shear strain is beneficial to improve the in_homogeneous strain distribution.展开更多
The hydraulic roll-bending device was studied, which was widely used in modem cold rolling mills to regulate the strip flatness. The loaded roll gap crown mathematic model and the strip crown mathematic model of the r...The hydraulic roll-bending device was studied, which was widely used in modem cold rolling mills to regulate the strip flatness. The loaded roll gap crown mathematic model and the strip crown mathematic model of the reversing cold rolling process were established, and the deformation model of roll stack system of the 6-high 1 250 mm high crown （HC） reversing cold rolling mill was built by slit beam method. The simulation results show that, the quadratic component of strip crown decreases nearly linearly with the increase of the work roll bending force, when the shifting value of intermediate roll is determined by the rolling process. From the first pass to the fifth pass of reversing rolling process, the crown controllability of bending force is gradually weakened. Base on analyzing the relationship among the main factors associated with roll-bending force in reversing multi-pass rolling, such as strip width and rolling force, a preset mathematic model of bending force is developed by genetic algorithm. The simulation data demonstrate that the relative deviation of flatness criterions in each rolling pass is improved significantly and the mean relative deviation of all five passes is decreased from 25.1% to 1.7%. The model can keep good shape in multi-pass reversing cold rolling process with the high prediction accuracy and can be used to guide the production process.展开更多
Including servo valve, hydraulic cylinder, mill and sensor and ignoring nonlinear factors, the linear dynamic model of hydraulic automatic gage control(HAGC) system of a temper rolling mill was theoretically derived. ...Including servo valve, hydraulic cylinder, mill and sensor and ignoring nonlinear factors, the linear dynamic model of hydraulic automatic gage control(HAGC) system of a temper rolling mill was theoretically derived. The order of the model is 4/4, and can be reduced to 2/2. Based on modulating functions method, utilizing numerical integration, we constructed the equivalent identification model of HAGC, and the least square estimation algorithm was established. The input and output data were acquired on line at temper rolling mill in Shangshai Baosteel Group Corporation, and the continuous time model of HAGC system was estimated with the proposed method. At different modulating window intervals, the estimated parameters changed remarkably. When the frequency bandwidth of modulating filter matches that of estimated system, the parameters can be estimated accurately. Finally, the dynamic model of the HAGC was obtained and validated based on the spectral analysis result.展开更多
基金Projects(2012CB619505,2010CB731703)supported by the National Basic Research Program of ChinaProject(CX2013B065)supported by Hunan Provincial Innovation Foundation for Postgraduate,ChinaProject(117308)supported by Postdoctoral Science Foundation of Central South University,China
文摘The realization way of snake rolling was introduced. Flow velocity, strain and stress distribution of 7075 aluminum alloy plate during snake rolling and symmetrical rolling were analyzed in Deform 3D. Effects of velocity ratio, offset distance between two rolls and pass reduction on the distribution of equivalent strain and shear strain were analyzed. The results show that flow velocity and equivalent strain on the lower layer of the plate are larger than those of the upper layer because of the larger velocity of the lower roll and the gap is increased with the increase of velocity ratio and pass reduction. The shear strain of roiling direction in the center point is almost zero during symmetrical rolling, while it is much larger during snake rolling because of the existence of rub zone. The shear strain is increased with the increase of velocity ratio, offset distance and pass reduction. This additional shear strain is beneficial to improve the in_homogeneous strain distribution.
基金Project(20050311890) supported by the Science and Technology Development Foundation of University of Science and Technology Beijing,China
文摘The hydraulic roll-bending device was studied, which was widely used in modem cold rolling mills to regulate the strip flatness. The loaded roll gap crown mathematic model and the strip crown mathematic model of the reversing cold rolling process were established, and the deformation model of roll stack system of the 6-high 1 250 mm high crown （HC） reversing cold rolling mill was built by slit beam method. The simulation results show that, the quadratic component of strip crown decreases nearly linearly with the increase of the work roll bending force, when the shifting value of intermediate roll is determined by the rolling process. From the first pass to the fifth pass of reversing rolling process, the crown controllability of bending force is gradually weakened. Base on analyzing the relationship among the main factors associated with roll-bending force in reversing multi-pass rolling, such as strip width and rolling force, a preset mathematic model of bending force is developed by genetic algorithm. The simulation data demonstrate that the relative deviation of flatness criterions in each rolling pass is improved significantly and the mean relative deviation of all five passes is decreased from 25.1% to 1.7%. The model can keep good shape in multi-pass reversing cold rolling process with the high prediction accuracy and can be used to guide the production process.
文摘Including servo valve, hydraulic cylinder, mill and sensor and ignoring nonlinear factors, the linear dynamic model of hydraulic automatic gage control(HAGC) system of a temper rolling mill was theoretically derived. The order of the model is 4/4, and can be reduced to 2/2. Based on modulating functions method, utilizing numerical integration, we constructed the equivalent identification model of HAGC, and the least square estimation algorithm was established. The input and output data were acquired on line at temper rolling mill in Shangshai Baosteel Group Corporation, and the continuous time model of HAGC system was estimated with the proposed method. At different modulating window intervals, the estimated parameters changed remarkably. When the frequency bandwidth of modulating filter matches that of estimated system, the parameters can be estimated accurately. Finally, the dynamic model of the HAGC was obtained and validated based on the spectral analysis result.
