Salt core

Patent Granted When a salt core (2) is formed by die casting, a melt is obtained first by heating and melting a mixed salt containing at least a potassium salt and a sodium salt. Then, the temperature of the melt is decreased to have the melt in a semi-solidified (solid-liquid coexisting) state. The semi-solidified melt is cast into a mold for salt core under high pressure and solidified therein, and the thus-formed salt core is taken out of the mold after solidification.