Rapid-Slug-Cooling-Technology (RSCT): A new approach for the production of thixocasting prematerial billets

Abstract

Prematerial slugs with a globular microstructure serve as feedstock for the thixocasting process. This microstructure is usually produced by inductive stirring of the melt in a modified continuous casting process. Extensive studies at the Foundry-Institute in Aachen show that, for many alloys, the main parameter for the production of suitable prematerial billets is the cooling rate. Therefore the new RSCT-Process (Rapid-Slug-Cooling-Technology) has been developed. With this process a fine and homogeneous microstructure of globular α-phase dendrites can be achieved. It enables, not only a rapid and efficient production of prematerial billets from aluminum and magnesium alloys, but also their in-house recycling. The produced RSCT-Slugs were metallographically analysed with the use of state of the art color etching techniques, which enable a precise measurement of the grain size and the examination of its morphology. In further investigations, the RSCT-Billets were reheated into the semi-solid state and pressed into test dies to examine the mechanical properties.