Mathematical Modeling of the Effect of Roll Diameter on the Thermo-Mechanical Behavior of Twin Roll Cast AZ31 Magnesium Alloy Strips

摘要

Although the Twin Roll Casting (TRC) process has been used inthe aluminum sheet production industry for more than 60 years,the usage of this process to fabricate magnesium sheets is still atits early stages. Similar to other manufacturing processes, thedevelopment of the TRC process for magnesium alloys hasfollowed a typical route of preliminary studies using a laboratoryscalefacility, followed by pilot-scale testing and most recentlyattempting to use an industrial-scale twin roll caster. A powerfultool to understand and quantify the trends of the processingconditions and effects of scaling up from a laboratory size TRCmachine to an industrial scale one is develop a mathematicalmodel of the process. This can elucidate the coupled fluidthermo-mechanical behavior of the cast strip during thesolidification and then deformation stages of the process. In thepresent study a Thermal-Fluid-Stress model has been developedfor TRC of AZ31 magnesium alloy for three roll diameters byemploying the FEM commercial package ALSIM. The rolldiameters were chosen as 355mm, 600mm and 1150mm. Theeffect of casting speed for each diameter was studied in terms offluid flow, thermal history and stress-strain evolution in the caststrip in the roll bite region.