Research Of Back-up Roll Load Spectrum Compiling Theory Of Hot Rolling Mill

Back-up roll is one the most important componnects of rolling mills,which is used to support work roll or intermediate roll,protects work roller from deflection so as to guarantee good strip shape.Under normal operating conditions,Back"uP roll grinding is performed in practice to romove surface and sub-subface initiated cracks.During the grinding operations,if removed amount is not enough,cracks off black and spalling may be caused later,if removed amount is excessive,the back-up roller life will be reduced and it's also wasteful in economy.So the reasonable grinding amount can avoid the shortages above.To determine the reasonable grinding amount needs to slove two key problems:one is a reliable contact experimental results which can reflect the mechanical proterty of back-up roller;the other is the typical load spectrum which is on behalf of the back-up roll load changes in a grinding cycle.The goal of this article is to work out a typical load spectrum.This article is based on F1 rack, apply the elastic mechanics thery to consummate the expression of influence function.On this basis,use the elastic deformation method and theoy of Hertz to build a mathematical model of influence function.This model includes five mechanic] equations that expressed by matrixs and vectors.The Newton iteration method is adopted to work out the contact pressure between rollers by program writting by Matlab software.The value of contact stress between roller and the half wide of contact surface are determined by the model.The maximum contact stress distribution along the axial between rolls is obtained. Analyzed the dominant stress whitch can cause the fatigue failure of back-up roller.Any position of dominant stress fatigue failure under contact can be calculated under the condition of given plate width and rolling force.Do the statistical analysis of rolling data from May 2011 to October 2011, a total of six months. Give different statistical method to calculate rotation of back-up roller under the condition of different rolling force and different plate width range. Form a two dimensional array by dividing plate width into 9 sections and dividing rolling force into 20 sections. Each subinterval of the array contains maximum contact stress, contact and a half wide, backup roll rotation. Select subinterval that contains more than 1000 rotation to form the final load spectrum.Analyse the ratio of rotation and steel volume from May 2011 to October 2011 and the value of equivalent fatigue damage,find that both of them fluctuate within a narrow range. The difference between fluctuation is acceptable which proves that compiling method of load spectrum is effective and feasible, load spectrum compiled by this method is typical and reasonable.