Papers by Author: Quan Yang

Abstract: Based on the analysis and simulation of the variable tension coiling process, integrated control strategy for strip flatness, thickness and tension has been proposed when the last stand adopts the control means of both position closed loop and pressure closed loop. The strategy pre-controls strip flatness and thickness according to the changing tension to decrease accommodation amplitude and enhance product quality. Practical application shows the strategy improves the control precision on the basis of ensuring the stable operation of unit.

Abstract: Edge drop of strip and sheet is a key technological issue besides of gauge control and shape control during the process of wide strip rolling, the reasonable control procedure of edge drop can increase the qualified product ratio, as well the quality and performance of product, it is especially effective for the silicon steel sheet, tin sheet and automobile body sheet. Therefore, more researchers focus on the edge drop of strip and its control technology in recent years. In this paper, a new strip profile control equation is established originally, according to the ways of strip shape control technology of large-scale tandem cold rolling mills. The new equation describes both the shape control and edge drop control. Some verification is developed in the equation based on the 1420mm UCMW tandem cold mill. The research result about mechanics of edge drop and it's control have been applied in tandem cold rolling mill. The good result is obtained according to the field measured data, and the control precision is increased greatly.

Abstract: Spring model is important restrictive factors to improve the precision of AGC control system. To improve the accuracy of strip gauge control, Study on various influencing factors of spring model has important significance in rolling process. Therefore, using ABAQUS finite element software, this paper establishes the whole stand model of strip rolling. The model is used to analyze variation factors of the strip width and bending force to impact the longitudinal stiffness of rolling mill and get calculation model of the longitudinal stiffness of rolling mill. Then, this paper considers influence of the roller thermal expansion and wear factors influence on spring model and establish compensation model. The corrected spring model was applied to 1780mm hot strip mill in a factory in China, taking 45 strip head samples for measurement, with the model error under 50µm.

Abstract: Based on 3D-FEM simulation, a model on influence of strip wave-shape upon the running deviation in the continuous annealing line was developed to improve the strip passing stability. A two-step model of FEM on hot strip rolling calculating the lateral flow of the metal improved the accuracy of strip shape control system.

Abstract: This paper expatiated on principles of high pressure abrasive water jet descaling; used GAMBIT and some experience parameters to create the geometry model of the nozzles and the outflow field; used Fluent to simulate the high pressure abrasive water jet under the condition of different jet standoff distance, different impact angle, different mix angle, different abrasive particle size, different abrasive concentration and different abrasive material. Through the analysis of the simulation results, this paper put forward the optimal selection of these parameters.

Abstract: With more and more process data acquired from manufacturing process, extracting useful information to build empirical models of past successful operations is urgently required to get higher product quality. Clustering is the important data mining methods, where feature extraction is a significant factor to ensure the accurate rate of clustering and classification. As a common non-linear feature extraction method, kernel principal component analysis (KPCA) uses the variance as the information metric, but the variance is not always effective in some cases. Since information entropy is nonlinear and can effectively represent the dependencies of features, the Renyi entropy is used as the information metric to extract the feature in this paper. Simulation data, Tennessee Eastman and hot rolling process data are used for model validation. As a result the proposed method has better performance on feature extraction, compared with traditional KPCA.

Abstract: In order to enhance the running deviation during the production of continuous annealing line (CAL) unit, the author conducted a research and revealed that the wave shape of incoming strip had significant effect on the deviation based on the statistic analysis of production data. Via finite element method analysis, a strip-furnace-roller dynamic simulation model was established, in which the perturbation of incoming strip to operation in contact zone was simulated to qualitatively research on effect trend of incoming wave shape on deviation. The result indicates that the strip with single edge wave causes more deviation than strips with other types of wave; in addition, wave height, wave length and wave width have contribution to the influence on the deviation. Accordingly, methods were adopted to optimize the upstream work procedure, and control single edge wave of incoming cold rolls can reduce accidents of slow-down and emergency shutdown caused by deviation.

Abstract: Towards the insufficiency of the research on asymmetric shape defects control, and the equipment of new asymmetric shape control device—inverse symmetric roll bending for UCM cold mill, in this paper, by ANSYS finite element simulation, high-precision rolls-strip coupling models were established, and the difference of control character among all the symmetric and asymmetric shape control methods were analyzed, then generalized overall shape setting control models with asymmetric shape control function was proposed. It was proved by field application that the control models can effectively control asymmetric and high-order shape defects with the coordination of all the symmetric and asymmetric shape control methods. Consequently, expansive research and apply prospect should be expected.

Abstract: The influence of the coiling temperature, ranging from 550 to 570°C, on the morphology and the phase composition of the oxide scale formed on the microalloyed low carbon steel for automobiles after hot strip rolling was investigated. Physicochemical characteristics of the oxide scales were examined and their formation mechanism was discussed. Thickness of the oxide scale is in the range of 8-11µm and decreases with a decrease of coiling temperature. The microstructure and phase composition, XRD analysis shows a large amount of magnetite (Fe₃O₄) and some sparse hematite (Fe₂O₃) exist on the surface of hot rolled strip when the coiling temperature reduces from 570 to 550°C. The coiling temperature substantially affects the internal microstructure and magnetite phase.

Abstract: Mill is always weighed by its longitudinal stiffness. The prediction precision of longitudinal stiffness related strip geometric accuracy. Taking 1700mm hot strip line as research object, stiffness of housing, bearing wall and roll was calculated by finite elements method(FEM), hydraulic system stiffness was obtained by theoretical formula. Analyzing vertical system and structural symmetry of mill, functional relationship between longitudinal stiffness and its components stiffness was derived according to series or parallel connection with various components. Longitudinal stiffness was the basis on thickness set-up model. Calculation result was verified by practical test.