Method of manufacturing expendable salt core for casting and expendable salt core for casting

Abstract

A die casting method for forming an expandable salt core includes, first, a salt mixture containing at least a potassium salt and a sodium salt is melted by heating to obtain a melt. Subsequently, the temperature of the melt is decreased to set the melt in a semi-solidified (solid-liquid coexisting) state. The melt in the semi-solidified state is injected into a metal mold under a high pressure and solidified. After solidification, the obtained expendable salt core is taken out of the metal mold.

1 - 13 . (canceled) 
   
   
       14 : A method of manufacturing an expendable salt core comprising:
 a first step of heating a salt mixture containing at least a potassium salt and a sodium salt to form a melt in a solid-liquid coexisting state in which a solid phase and a liquid phase coexist;   a second step of charging said melt in the solid-liquid coexisting state into a core mold; and   a third step of solidifying the melt in the mold to mold an expendable salt core for casting.   
   
   
       15 : A method of manufacturing an expendable salt core according to  claim 14 , wherein:
 in the first step, the salt mixture is heated to be set in a liquid-phase-only state, and thereafter the salt mixture is cooled, thus forming the melt in the solid-liquid coexisting state.   
   
   
       16 : A method of manufacturing an expendable salt core according to  claim 14 , wherein:
 in the second step and the third step, the mold is charged with the melt under pressure and the melt is solidified.   
   
   
       17 : A method of manufacturing an expendable salt core according to  claim 16 , wherein:
 the pressure is applied evenly until the mold is opened.   
   
   
       18 : A method of manufacturing an expendable salt core according to  claim 14 , wherein:
 the salt mixture is formed of only potassium ions, sodium ions, chloride ions, and carbonate ions; and   a molar ratio of the potassium ions in all the cations is about 50 mol % at maximum and a molar ratio of carbonate ions in all the anions is about 30 mol % to about 80 mol %.   
   
   
       19 : A method of manufacturing an expendable salt core according to  claim 18 , wherein:
 in said salt mixture, the molar ratio of the potassium ions in all the cations is 40 mol % at maximum and the molar ratio of carbonate ions in all the anions is 50 to 70 mol %.   
   
   
       20 : A method of manufacturing an expendable salt core, the method comprising:
 molding an expendable salt core by heating a salt mixture containing at least a potassium salt and a sodium salt to form a melt in a solid-liquid coexisting state in which a solid phase and a liquid phase coexist;   charging the melt in the solid-liquid coexisting state into a core mold; and   solidifying the melt in the mold.   
   
   
       21 : The method of manufacturing an expendable salt core according to  claim 20 , wherein:
 the melt in the solid-liquid coexisting state is formed by heating the salt mixture to be set in a liquid-phase-only state, and thereafter cooling the salt mixture.   
   
   
       22 : The method of manufacturing an expendable salt core according to  claim 20 , wherein:
 the expendable salt core is formed by charging the mold with the melt under a pressure and then solidifying the melt.   
   
   
       23 : The method of manufacturing an expendable salt core according to  claim 22 , wherein:
 the pressure is applied evenly until the mold is opened.   
   
   
       24 : The method of manufacturing an expendable salt core according to  claim 20 , wherein:
 the salt mixture is formed of only potassium ions, sodium ions, chloride ions, and carbonate ions; and   a molar ratio of the potassium ions in all cations is about 50 mol % at maximum and a molar ratio of carbonate ions in all the anions is about 30 mol % to about 80 mol %.   
   
   
       25 : The method of manufacturing an expendable salt core according to  claim 24 , wherein:
 the molar ratio of the potassium ions in all the anions is about 40 mol % at maximum and the molar ratio of carbonate ions in all the cations is about 50 mol % to about 70 mol % in the salt mixture.   
   
   
       26 : The method of manufacturing an expendable salt core according to  claim 20 , wherein:
 the expendable salt core includes a core to mold a water jacket arranged to water cool a closed-deck type cylinder block of engine.