Research On Shape Control Characteristics Based On Contact Pressure Distribution Between Rolls

As the equipment to transfer the rolling force in the rolling process,the backup roll directly participates in the whole rolling process.Because the backup roll is in direct contact with the work roll in the rolling process,the contact pressure distribution between the backup roll and the work roll becomes extremely important.On the one hand,it directly affects the wear form of the backup roll,on the other hand,its distribution form will also affect the shape regulation.At present,although there are many studies on the contact pressure between rolls,they mainly focus on the influence of different roll shape configuration on the distribution form of contact pressure between rolls and the optimization of support roll shape for the purpose of uniform contact pressure between rolls.There is less quantitative research and prediction on the influence of different control means on the distribution of contact pressure between rolls,and there is also a lack of sufficient research on the influence of the distribution form of contact pressure between rolls on the shape control performance,The above factors have certain significance for the improvement of flatness control level in industrial production.Taking a 1800 mm hot rolling production line as the research object,combining theoretical analysis,finite element simulation and industrial production,this thesis systematically analyzes the influence of shape control means on the distribution of contact pressure and shape control performance between rolls under different roll system configuration and wear forms,deduces the prediction formula of contact pressure between rolls,and establishes the wear prediction model of backup roll based on contact pressure between rolls.The main work and achievements of this thesis are as follows:(1)The finite element simulation software is used to establish two typical finite element models of roll system used in the field,calculate the distribution form of contact pressure between rolls under different strip specifications and control means,quantify the influence of different specifications and control means on the distribution characteristics of contact pressure between rolls,and obtain the overall influence trend of more specific different parameters on the distribution characteristics in the whole variation range,At the same time,the influence of different contact pressure between rolls on the shape control characteristics of the rolling mill is analyzed.It is found that the influence on the roll gap shape under different roll shape configuration shows obvious differences,and the simulation analysis results are verified combined with the actual production data.(2)On the basis of a large number of measured and simulated data,combined with theoretical analysis,the prediction model of contact pressure between rolls is established.Through calculation and verification,the results of the established mathematical model of contact pressure are in high agreement with the results of finite element simulation.It is found that the distribution trend of contact pressure predicted is basically the same as that of support roll wear extracted on site,The prediction model of contact pressure between rolls can predict the distribution trend of contact pressure at different stages of the service cycle of backup roll,and avoid Roll Spalling by effectively adjusting the rolling plan.At the same time,it can also provide a certain theoretical basis for the prediction of backup roll wear.(3)Considering various factors affecting roll wear,a wear prediction model of backup roll based on contact pressure between rolls is established by using slice method.The model is a multi peak and nonlinear semi empirical formula,and its parameters are difficult to determine.Based on a large number of field measured data,the parameters of roll wear model are optimized by genetic algorithm;The wear prediction results of backup roll are in good agreement with the measured values,which provides a good theoretical analysis basis and production guidance for improving the wear prediction accuracy and shape control technology level of backup rollers in different service stages.