Tandem Rolling Process Simulation And Nonlinear Online Model Research For UCM Mills

In the cold-rolled strip rolling process, control level of product quality plays adecisive role. In general, the cold-rolled strip rolling process is researched by theapproximate linear mathematical model. But in the actual production process, thecold-rolled strip process includes multiple factors, strong coupling, nonlinear. In this paper,the nonlinear finite element method and the neural network method are combined toresearch cold-rolled strip rolling process. The combined method provides the foundationfor cold-rolled strip rolling process control accurately and quickly.In this paper, in order to forecast the rolling force accurately and quickly, atwo-dimensional dynamic model is established by nonlinear elastic-plastic finite elementmethod. The effects of entry thickness, reduction rate, forward tension, backward tension,friction coefficient, deformation resistance and work roll diameter on the rolling force areanalyzed by the model. The neural network of rolling force prediction is established. Theneural network model is trained by the simulation results of finite element model. Thetrained network model can forecast rolling force accurately and quickly.In the cold-rolled strip rolling process, shape control and gauge control are coupledtogether. Adjusting roll gap affects not only gauge but also shape. Adjusting roll bendingforce affects not only shape but also gauge. In order to set shape and gauge accurately, therelationship of shape set and gauge set should be researched. This paper systematicallyanalyzes the equations and models of UCM mill, including mill stiffness equations, gaugeequation, crown equation, shape and gauge coupling equation, intermediate roll shift setmodel, roll bending force set models and roll gap set model. The set strategy of shape andcrown integrated is presented. The three-dimensional dynamic UCM mill model isestablished by nonlinear elastic-plastic finite element method. The horizontal and verticalstiffness of the rolling force, the horizontal and vertical stiffness of the work roll bendingforce, the horizontal and vertical stiffness of the work roll bending force are calculated bythe model. The effects of the intermediate roll shift on the horizontal and vertical stiffnessof rolling force are calculated by the model. The set strategy of shape and crown integrated is verified by the finite element model. The gauge and shape meet therequirements after set.This paper systematically analyzes the effects of entry thickness, reduction rate,forward tension, backward tension, friction coefficient, deformation resistance, strip width,entry crown, work roll bending force, intermediate roll bending force, intermediate rollshift, work roll diameter, intermediate roll diameter and backup roll diameter on stripcrown. In order to forecast strip crown quickly and accurately, neural network is used toestablish a network model of cod-rolled strip crown forecast.In order to control the lateral thickness difference, this paper analyzes the basicconcept of actuator effectiveness and presents the lateral thickness difference actuatoreffectiveness expression. The lateral thickness target curve of shape set process is derived.The effects of work roll bending, intermediate roll bending, intermediate shift on striplateral thickness difference, lateral displacement, roll bending and roll flattening areanalyzed by finite element model. The neural network model of strip lateral thicknessdifference forecast is established. The lateral thickness difference actuator effectiveness ofwork roll bending, intermediate roll bending, intermediate shift are calculated by finiteelement model. The neural network model of strip lateral thickness difference actuatoreffectiveness forecast is established. The shape set process is analyzed. Shape is set byproportional crown method and actuator effectiveness method. The results andcharacteristics of the two methods are compared. The effects of work roll bending,intermediate roll bending, and intermediate shift on edge drop are analyzed. Therelationship of edge drop and adjustment amount is researched. The shape set methodbased on actuator effectiveness is improved. The shape set model based edge drop andcentral crown is presented.Based on above research findings, industrial experiments are conducted on six-high900UCM cold tandem mills. Rolling force prediction model, strip crown predictionmodel and FEM model are verified by the experiments.