FILTER FOR CASTING ALUMINUM AND ALUMINUM ALLOY

PURPOSE:To enable the use of a sprue and runner as return materials as they are by coating the surface of a net body formed of a core material made of aluminum with an inorg. binder contg. inorg. short fibers. CONSTITUTION:The core material 1 is coated with the inorg. binder which hardly reacts with the aluminum or the aluminum alloy. The inorg. binder having the lower thermal conductivity than the thermal conductivity of metals hinders the rapid heat transfer from molten metal to the core material 1. In addition, the harmful deformation of the net body 2, such as destruction of meshes, is prevented by the strength of the inorg. binder film. The inorg. short fibers 3a are mixed into the inorg. binder. The short fibers 3a act to prevent the dislodgment of the film of the inorg. binder from the core material 1 even if the film is partly cracked by rapid heating of the inorg. binder at the time of casting. The intrusion of the inorg. binder into a casting is thus prevented.