The Optimization And The Application Of The Plate Profile Model

As one of the most important qualities of the plate, plate profile has greatly affected the increase of plate yield and the quality of further processing of the plate. The rapid development of high precision manufacturing also enhanced the demand for the high quality of the product. The profile control has become a hot topic of rolling control after the gauge control for the popularity of the plate shape control equipment. The accuracy of the plate profile model is significant to the implement of plate profile control. Roll deformation model, plate profile model and bending force model are core models for plate profile control. In this paper, depending on the analysis of influence factors on the plate profile, plate profile theories and methods of plate profile control device, roll deformation model has been improved to build up plate profile calculation model and optimal bending force calculation model, which is a part of the cooperated project between RAL and a domestic plate production company. The measured data from the plate site was used to test the developed plate profile calculation system and the results have been discussed. The major researches are as follow:(1) Roll deformation model was improved. The original work roll contour and the original backup contour were deduced by roll contour, thermal crown curve and relative wear capacity curve. The roll flattening calculation method brought forward by Foppl was revised to approach to the actual condition of roll flattening by the introduction of the equivalent elastic modulus, the distribution of special contact force. With the reverse conic fits between roll flattening and special contact force between work roll and backup roll, the lower surface contour of the backup roll, the work contours and the plate contour can be calculated by the integral iterative method. It is aimed at simplifying the calculation of roll flattening and raising the accuracy of roll deformation model.(2) The plate profile model was built up. The influence, such as plate thickness, plate crown at the delivery side, rolling force, etc, on the plate profile at the exit side have been investigated. The contribution of plate profile at the delivery side and the work roll contour were regressed with the rule of secondary polynomial fitting by Cramer’s principle and Least-square method. The plate and work roll were discretized. Newton’s linear interpolation method was adopted to guarantee the coherence of the relative position coordination. Taken the consideration of plate profile at the delivery side, the work roll contour, the phenomenon of edge drop of the plate during rolling, and so on, the plate profile at the exit side was calculated.(3)The optimal bending force calculation model was carried out. The relationships among crown, thickness and flatness of the plate at the exit side were searched on the analysis of the impression of rolling force, plate size, roll crown, roll wear, etc on the determination of bending force. Relied on the relationship between bending force and plate crown difference at the exit side, and the relationship between bending force and plate flatness at the exit side, the optimal bending force was iterated with the dichotomy method and the secant method. It has sped up the convergence of the optimal bending force and increased the calculation accuracy.(4) The plate profile calculation system was designed. The off-line test has been performed by the application of the data collected from one of the plate production sites in the following two ways:the plate profile calculation in every single pass and the plate profile calculation in full schedule. The results showed that plate profile satisfied the requirements of good plate profile condition and plate crown at the exit side trended to decrease as the whole in the rolling. Besides, plate crown at the exit side after the final pass was always the minimum one of all the plate crown values. When the ratio of the width to thickness of the plate was less, the difference between the calculated value and the measured value of the plate crown at the exit side was less. It is reflected on the feasibility of the further online application of this plate profile calculation system to some degree.