MECHANISM OF OXIDE GENERATION AND MIXING INTO ALUMINUM INGOT IN CAST START PHASE

摘要

During aluminum semi-continuous casting, many oxides are generated by the turbulent metal flow during the metal feeding from the casting launder to the nozzle, the distributor, the glass cloth filter (GCF) and the mold. Especially, this is remarkable in the cast start phase. These oxides possibly cause sheet defects. In this study, we investigated the effect of the casting conditions such as the initial metal feeding speed, distance between the GCF and the bottom block and inert gas atmosphere in the mold by determining the qualities of the rolled sheets and ingots in order to clarify the mechanism of oxide generation and mixing into the ingot. Consequently, most of the oxides were generated at the end of the distributor and on the bottom block. The oxides on the bottom block were carried away with metal flow and finally were mixed in the solidification zone. Therefore, it was effective for reducing the oxides to seal the mold with inert gas and to shorten the distance between the GCF and the bottom block.