Finite Element Analysis And Optimization Of Grinding Procedure For Back-up Roll In Hot Rolling

Back-up roll is one of the most important components of rolling mills, which supports work roll or intermediate roll, protects work roll from deflection so as to guarantee good strip shape. The quality of back-up roll could impact the properties and productivity of plates. Consequently, regular back-up roll grinding is performed in practice to remove surface and sub-surface initiated cracks. If removal amount is not sufficient enough during the grinding operation, cracks could propagate and even the flaking and spalling may occur later, causing significant economy losses. However, the effective service life of back up roll will be reduced if removal amount is excessive, and it’s also wasteful in economy. The objective of this dissertation is to optimize grinding procedure to assure sufficient and logical stock removal.Basing on nonlinear elastic-plastic finite element method (FEM), thermal-mechanical coupling FEM and advanced contact analysis technology of MSC.MARC software, a three-dimension finite element simulation of hot strip rolling process is done according to1880hot strip mill of Baosteel. Rolling forces and stress fields within back-up roll are accurately calculated. Stress fields distribution during rolling process are dynamically analyzed, including stress fields at different time and its radial and axial distribution within roll. Furthermore, the efforts of different plate widths and reductions on stress fields are analyzed. The simulated rolling forces are in good agreement with the theoretical values calculated by SIMS equation. Meanwhile, the distributions of stress fields within back-up roll accord with classical Hertz theory.Defines the concept of value of cumulative fatigue damage, it is described as the characteristic parameter of damage, and the new grinding policy is established based on the foundation of current grind policy of back-up roll.The main research contents can be summarized in the following points:1) Three-dimension finite element model of4-high hot strip mill is established by using MSC.Marc software.2) The distributions of stress fields within back-up roll are obtained.3) Studies the effects of different plate widths and reductions on stress fields.4) Study mechanics of two different rolling contact fatigue (RCF) spalling, surface initiated cracks and sub-surface initiated cracks.5) Statistical analysis of product datum of1880hot strip mill of Baosteel in last17months6) Taken cumulative fatigue damage value as parameter of damage, optimize the new grinding procedure based on cumulative fatigue damage value.