Tailoring the As-Cast Microstructure of Twin-Roll Cast AA3105 Alloy Produced by St/Cu Shell Pair

Abstract

Extracting the heat from the liquid metal with the help of the water-cooled caster rolls (designed with core and shrink-fitted shell) and then reaching as-cast strip in various thicknesses with different casting speeds generate the phenomena of the twin-roll casting (TRC) process. In order to increase productivity (combination of the casting speed and as-cast strip thickness) which is one of the most important outputs of the TRC, different shell materials having different heat transfer coefficient rate could be used. In case of using St/Cu (steel-copper) shell pair, higher productivity rate could be obtained. However, as-cast microstructure of the materials could have some differences such as behavior of the centerline segregation and grain structure compared to the sample produced by St/St (steel-steel) shell pair. In this study, casting parameters (setback, roll speed, strip speed, and thickness) are changed in order to observe the differences such as centerline segregation and grain structure close to the surfaces.