FILTER MEDIUM FOR MOLTEN METAL

摘要

PURPOSE:To prevent a molten metal which is filtered from being contaminated by the binder component of filter media by molding specific high boiling aggregate grains by using the inorg. binder material having a specific compsn. and calcining the molding, thereby forming the filter media for the molten metal. CONSTITUTION:A defectless ingot is produced by filtering the metallic oxides and non-metallic inclusions such as small splinters of refractories in the molten metal at the time of casting the molten metal to the ingot. The filter media having fine open cells are produced as the filter media for the molten metal of this case by adding 4-20pts.wt. inorg. binder material consisting of a mixture composed of 15-80% B2O3, 2-60% Al2O3, and 5-50% MgO as the binder with 100pts.wt. aggregate particles of SiC, Si3N4, electro-cast alumina, and sintered alumina, molding the mixture and calcining the molding. Since SiO2 and CaO are not incorporated into the binder of the filter media, the intrusion of Si and CaO into the molten metal which is filtered and the generation of cracks and pinholes at the time of rolling the ingot are obviated.