Study On Simulate And Suppress Chatter Of Large Strip Tandem Cold Rolling Mills

In the background of the rapid development of modern industry, tandem cold striprolling mills embodies its key position in the steel industry. The demand of strip isincreasing and the quality of strip surface is required higher and higher for industries. Withthe increasing speed and intensity of the rolling mill, the phenomenon of chatter is oftenoccurred in the mill vertical vibration system. The vibration not only affect the quality ofthe product, but also undermine the rolling equipment. So, the rolling production will beseriously affected and the production efficiency will be reduced. Then, how the structureparameters and the process parameters influence the chatter will be needed to study. Therecan provide a theoretical basis for the optimization of dynamic characteristics of thesystem and inhibiting chatter.Firstly, A model of nine degree of freedom for the vertical vibration of large stripsix-roll stand rolls system in a cold tandem mill is developed. According to the naturalfrequency and modes by solving the model of vertical vibration, the influence of eachmode for vibration characteristics of six-roll mill is analyzed. Then, the natural frequencysensitivity to mass and stiffness, energy distribution of each part and Flexibility of themodes are also analyzed. It provides guidance for the design of the dynamic characteristicsof mill.Secondly, a model of rolling force is built under consideration of vibration. Besides,the model of resistance, the model of friction coefficient and the model of sliding whichinfluence the rolling force changing are listed. After considering the change in tension andthickness between adjacent stand, the nine degrees of freedom chatter model are built.There can provide theoretical model for studying chatter. Then, the influence law ofchanges in tension, rolling speed and friction factor for chatter is researched. Theinfluence law of each parameter for chatter in the three consecutive stands rollingsimulation using numerical methods of Runge-Kutta-Fehberg by myself can be improvedby using chatter model.Thirdly, according to the influence low of structure parameters and technology parameters for chatter, five methods on rolling structure and rolling technology areproposed to solve chatter in practical production. And, the feasibility of those methods areverified by simulation.Finally, the software of simulating and inhibiting chatter of tandem cold rolling millsis developed. It can study the stability of rolling process in offline and instruct actualproduction qualitatively.