Study On The Nonlinear Rolling Characteristic And Vibration Of 4200 Mill

With the rapid development of modern industrial technology, the requirement of the medium steel plate quality for the various all walks of life is much higher than before. Because the rolling process of the medium steel plate is a complex nonlinear system, the accuracy of traditional rolling control model can not fulfill the demand of the modern rolling technology. The vibration of rolling process affects the working stability of rolling mill and the quality of steel product. In order to improve the products' quality and guarantee the safety operation of rolling mill, it is necessary to optimize the control model of rolling process and explore the rolling vibration laws.The main influencing factors for the metal deformation resistance in medium steel rolling process are analyzed. Basing on the actual data, a neural network prediction model of 4200 medium plate rolling mill for predicting the metal deformation is built by several frequently used neural networks. The neural networks structures are optimized. Compared to the prediction accuracy of other networks models, the RBF neural network is proved to be the best network for the model which has efficiently promoted the prediction accuracy.In this paper, the twisting vibration of the 4200 medium rolling mill in rolling process is analyzed. A nonlinear twisting vibration model on main transmission system is made by using the theory of mechanical vibration and the knowledge of theoretical mechanics. The phase graph, Poincare graph and the time-history graph of the system can be obtained by the simulation of MATLAB software. The twisting vibration laws of main transmission system in rolling process are analyzed by nonlinear qualitative theory. The first order approximate solution of the model vibration equation is attained by multiple-dimensioned method. The influence rules of nonlinear damping and stiffness to the system stability can be got by analyzing the amplitude frequency response curve, which provides theory evidence for reducing malfunction of the mill.The six degrees vertical vibration model of the 4200 medium plate's roller system is built. The frequency and the main vibration mode of the roller system can be got by calculating. The roller movement law in rolling process and the dangerous working frequency are discovered by analyzing the main vibration graph. It provides a method to improve the roller system's structure. A nonlinear roller system vertical vibration is built with considering the roller system nonlinear factors. The bifurcation graph of the roller displacement which changes with the excited frequency changing is also got by MATLAB simulation. With the phase graph, Poincare graph of different working conditions and the maximum Liapunov index, the system movement law how the periodic motion changes into the chaos can be found. It has a directive to the improvement of the rolling section steel.