2.5D FEM Study and Optimization of Roll Pass Design in Roughing Mill Group

Abstract

The subject of the paper is a study of the material behaviour during hot rolling. The process considered is a rolling of round bar in roughing mill group which consist of four passes. The computer simulation of the process shows that the local plastic deformations which appear in the material are extremely large. This fact can leads to extension of surface defects. The dependences of maximum local plastic deformation on geometrical parameters of the calibres have been obtained and analysed during this study. The investigations performed, led to the development of new roll pass design which almost halved the maximum value of local plastic deformation in the material during the rolling. Since full 3D FEM models needs significant amount of computer memory and CPU time, it was not suitable for the performed study which involves a bulk of simulations with different initial conditions. Therefore, the quick algorithms for simulation of rolling processes which based on so-called “2.5D” method have been used. This method, due to number of simplifications, is significant faster then conventional 3D FEM, and at the same time it allows to reach good accuracy of the model. The developed computer software SPLEN(Rolling) which implements “2.5D” FEM simulations was applied for computations and analysis of the results. This software is able to predict the shape evolution of rolled material, as well as distributions of strain, strain rate and temperature within the volume of deformation zone. It has been shown that computer simulation based on “2.5D” FEM with SPLEN(Rolling) software can by efficiently used for optimization of technological procedures in rolling industry.