Temperature and deformation homogeneity of AZ31 magnesium alloy in HRR

The effects of different process parameters on the temperature and deformation pattern during heated roll rolling (HRR) of AZ31 magnesium alloy strip at room temperature were investigated using the thermal-force coupled finite element method. Additionally, experiments and tissue properties tests on strips rolled on multi-pass heated roll without inter-pass annealing were carried out. The results show that the heated roll rolling can achieve the strip temperature rise and rolling deformation in parallel. Under the effect of contact heat transfer and heat conduction, the temperature difference between the surface and the core of the strip first increases and then decreases. The increase in entry thickness, roll surface temperature and reduction rate and the decrease in rolling speed make the strip temperature rise more significant. The strain rate difference between the strip surface and the core fluctuates up and down periodically, reducing the entry thickness and rolling speed is beneficial to the regulation of deformation uniformity. The condition with roll surface temperature of 300-400 ℃, rolling speed of 0.01-0.1 m/s and single pass reduction of 20%-30% is help to improve temperature and deformation uniformity. After multiple pass rolling with heated roll, the strip has superfine grain size of less than 1 μm, with an average grain size of about 2-3 μm. Furthermore, the maximum elongation of the strip is about 30.7% and the tensile strength reaches 372 MPa, which is a good mechanical property. © 2023 Central South University of Technology. All rights reserved.