Research On Influencing Factors Of Flatness Of 20-High Cold Rolling Mill

With the continuous development of my country’s economy,the precision requirements for thin strips are getting higher and higher,and ordinary four-and six-high rolling mills have been unable to meet the processing requirements.The 20-high cold rolling mill has many advantages such as small roll diameter,large overall rigidity,and shape adjustment mechanism(ASU),which can roll thinner strip steel.At present,the 20-high cold rolling mill mainly conducts research on the deformation and stress of the roll system,and rarely involves the research on the deformation process of the strip.This paper takes a 20-high rolling mill in a steel mill as the research object,establishes a finite element model with actual dimensions,and simulation and analysis of the deformation process of the strip during the rolling process.First,according to the geometric dimensions of the 20-high cold rolling mill,a three-dimensional model of the 20-high rolling mill is established based on Solidworks,and establish the finite element model of the 20-high rolling mill through ANSYS/LS-DYNA module.The explicit dynamic algorithm is used to solve the rolling process of the rolling mill by finite element method.Analyze the rolling force and strip stress distribution in the cold rolling process,use APDL language to establish the strip section curve after rolling,and calculate and analyze the strip shape index based on the flatness of the shape index.Then,based on the finite element model of the 20-high rolling mill,the corresponding relationship between the various parameters(width,thickness,tension,speed)and the shape index in the strip rolling process is studied.Comparative analysis of the influence of multiple parameters on flatness.Analyze the influence of different ASU adjustment schemes on the shape of the plate,and obtain the influence of the adjustment parameters of the backing roller backing bearing at different positions on the plate shape,,and provide a reference for obtaining high-precision strips;In reality,when there are defects before cold rolling of the strip,established a 1/2 model of a 20-high cold rolling mill through ANSYS Workbench,the statics explicit algorithm is used to simulate the rolling of the strip with initial defects.The strip has two different defects in the initial convexity and concavity,and the change rule of the strip shape after rolling is summarized.Finally,a flatness control model is established based on BP neural network,introduce the corresponding relationship between different process parameters and flatness index of rolling process obtained by simulation to complete the prediction of flatness index;and use genetic algorithm and particle swarm algorithm to optimize the shape control model,obtain a shape control model with smaller errors and higher accuracy.