Study On Coupling Vibration Of F2 Of 1580 Hot Strip Mill

With the development of modern iron and steel enterprise,the demand and quality requirement of hot rolled strip are increased year by year.However,the quality of rolled piece is greatly limited due to the vibration of rolling mill.The vibration of rolling mill is prone to accelerate the wear and tear of components and parts,even causes safety misadventure when it is serious,and causes huge economic losses.Therefore,in order to understand the rolling process,clarify the mechanism of abnormal vibration,and find the vibration suppression methods,it is necessary to make a profound study of the rolling mill vibration.The establishment of accurate rolling dynamic model is the basis of studying rolling mill vibration.However,in the existing research,the influence of rolling springback and multiroll equilibrium is often ignored in the establishment of rolling process model,which leads to errors in the research results.And,in order to simplify calculating,the rolling mill structure is too simplified in the establishment of rolling mill vibration model,such as the gap between the roll chock and rolling mill stand.In addition,many coupling factors including coupling characteristics of rolling parameters in the horizontal,vertical,and torsional directions are also rarely considered.Therefore,it is necessary to establish the rolling dynamics model by considering the rolling springback,side gap,multiroll equilibrium,and various coupling factors.The object of study of this article is F2 of 1580 hot tandem strip mill.The effects of coupling factors in the horizontal,vertical,and torsional directions,side gap,multiroll equilibrium,and rolling springback are considered.And,the coupling vibration of rolling mill is studied by means of analysis methods including experimental analysis and theoretical analysis.The main contents of this paper are as follow:(1)With the abnormal vibration of F2 of 1580 hot tandem rolling mill in production as the research background,the actual vibration signals are analyzed.It is found that40.96 Hz and 44.97 Hz are the frequencies that cause the beat vibration phenomenon of horizontal-vertical-torsional coupling vibration.And,it is concluded that the operating side of rolling mill has vibration excitation source and the torsional vibration is forced vibration by comparing the start time of vibration signals.This provides thought for follow-up study.(2)With the typical four-high hot rolling mill as the research object,the steady rolling process model is established by considering the springback and multiroll equilibrium.And the accuracy of the model is verified by actual data.Then,the dynamic rolling process model with nonlinear factors is established by considering the coupling of mechanical parameters in the horizontal,vertical,and torsional directions,separating the thickness and speed,and taking the variation of strip thickness at entry as the excitation.This provides basis for studying the nonlinear vibration characteristics of rolling mill.(3)The structure models in the horizontal,vertical,and torsional directions are established by considering the differences between backup roller and work roller,the offset,and the gap between work roll bearing chock and frame.Then,the horizontal-vertical-torsional coupling structural model of rolling mill is established by considering the coupling relationships of the structural models.Finally,The piecewise nonlinear horizontal-vertical-torsional coupled vibration model of rolling mill is established by coupling the dynamic rolling process and coupling structure model of rolling mill.(4)The amplitude-frequency characteristics of the system under different conditions are studied by using the average method,for further analysis of the vibration characteristics of rolling mill.It not only verifies the accuracy of the model,but also provides theoretical references for the vibration suppression of rolling mill.The results show that the vibration amplitude of the system can be reduced by reducing the side gap,reducing the external excitation,and increasing the first power damping.In particular,eliminating the side gap can make the jumping phenomenon of vibration amplitude disappear and make the system become stable.(5)The stability of rolling mill vibration under different conditions are studied by using numerical simulation.The results show that the stability of the system can be improved by reducing the external excitation,number of excitation sources,and side gap.Based on the previous conclusions and the actual working conditions,it is proposed that the vibration suppression can be achieved by optimizing the friction and lubrication conditions on rolling interface and reducing the side gap.