Optimization of shear enhanced rolling parameters for grain refinement in magnesium AZ31B alloys

Abstract

Shear enhanced rolling (SER) is a novel patented technique that aims to enhance the grain uniformity across the rolled section, hence improve the mechanical properties in terms of yield. SER depends on applying a transverse loading (TL) between a two-stage conventional rolling setup. Shearing stresses are influenced due to this TL at the core of the rolled section leading to a finer and more uniform grain size distribution across the section. Previously, A comparison between conventional rolling and SER was conducted on magnesium alloy AZ31B to prove the concept of SER. In this manuscript, the optimal setup of SER is investigated by optimizing the vertical displacement of the TL, termed SER-V. The optimal SER-V is found to be the value that allows for maximum contact between the rollers and the rolled billet. Using analytical geometry and MATLAB, the analytical value of SER-V is obtained for any SER setup. To validate the new finding, a computational comparison between adjusted SER setups (for two rolling spans), conventional rolling, and conventional rolling with maximum rolling draft, is conducted using ABAQUS\Explicit. Knowing that Mg AZ31B obeys the Hall-Petch relationship, the grain sizes were calculated along the cross-section. The results confirmed that the optimized SER setups exhibit the best grain uniformity and yielding strength, achieving this advantage in a single rolling pass. Finally, this work clarifies that SER produces enhanced mechanical properties in a manner that is cost saving relative to conventional rolling options.