Investment casting with improved melt filling

摘要

Molten metallic material is cast into a mold that is made with a barrier to reduce gas permeability through a mold wall that forms on its innermost side a mold surface for contacting the molten metallic material. The molten metallic material is gravity cast into the mold residing in a furnace in a casting chamber under a first pressure, such as subambient pressure. Then, a gaseous pressure is provided in the casting chamber higher than the first pressure rapidly enough to reduce or eliminate the presence of localized voids in the casting solidified in the mold.