Comparisons of flow behavior characteristics and microstructure between asymmetrical shear rolling and symmetrical rolling by macro/micro coupling simulation

Abstract

A new rolling method of asymmetrical shear rolling is applied to solve heterogeneous strain and uneven microstructure distribution of thick plate preparation in symmetrical rolling. Coupled finite element models (FEM) and cellular automata (CA) models are established to compare strain and temperature characteristics and microstructure evolution during multi-pass rolling of two rolling ways. Different recrystallization mechanisms are taken into consideration in coupled models of multi-pass rolling. The results show that equivalent strain distribution is asymmetrical in asymmetrical shear rolling and the value at center point is 16% larger than that in symmetrical rolling due to accumulated shear deformation. The temperature at lower layer of the plate in asymmetrical shear rolling is higher, which results in faster metal flow and larger strain. The temperature variations in relation to time at different positions of the plate are fitted. Microstructure evolution for multi-pass rolling is studied and higher recrystallization fraction and finer grain size appear at center point of plate in asymmetrical shear rolling. Rolling experiments are conducted and the results of strain and microstructure agree with simulation results. The coupled models provide guidance for flow behavior and microstructure analysis at macro/micro level.