Asymmetric Rolling Theory Based on Numerical Analysis Using Orowan's Theory

An asymmetric rolling possesses advantages in energy consumption, strip flatness of hot strip because of decrement of rolling force. And as we say another merit, asymmetric rolling enable us to control inner microstructure rolled with high reduction and with large shear strain. Introducing a single driven rolling to tandem hot strip rolling, we produce fine grain hot strips industrially. We need numerical deformation analysis model to combine microstructure evolution model to predict them. An asymmetric rolling theory based on numerical analysis using slab method, Orowan's theory, is proposed. The most important effect of an asymmetric rolling is the relative displacement of neutral points on the rolls. This displacement of neutral points generates a cross shear region in which the surface friction forces are in opposite directions. To formulate rotational equilibrium equation in the cross shear area, we consider the reasonable distribution for the pressure difference between the rolls. This developed model permits rolling load, rolling torque, stress distribution and strain distribution as a function mill geometry and strip reduction with quite short computing time. Numerical simulation results are presented and compared with results of FEM, which is most reliable to analyze plastic deformation today, and with results of laboratory rolling. Accuracy of new theory is roughly equal to accuracy of FEM.