Soluble core for high-pressure casting and manufacturing method thereof

Abstract

According to the method for manufacturing a soluble core for high pressure casting, the method for manufacturing a core by dispersing a heat-resistant hard ceramic powder in a water-soluble chemical salt having a melting point 140° C. to 260° C. lower than a melting point of a cast metal and a heat capacity of 90 J/(mol·K) or more is a very useful technology that can easily manufacture a core for high pressure casting of metals such as aluminum and magnesium, and a method for extracting a core from casting can also be simply performed by heating and extracting the core at a temperature equal to or lower than the melting point of the cast metal, and since the core material can be recycled, it is very advantageous in terms of productivity and economy.

1 . A method for manufacturing a soluble core for high pressure casting, comprising:
 a step of manufacturing a water-soluble chemical salt mixture having a melting temperature of 390° C. to 520° C.;   a step of uniformly dispersing and mixing a heat-resistant hard powder into the above water-soluble chemical salt mixture to manufacture a molten chemical salt having a heat capacity of 90 J/(mol·K) or more; and   a step of injecting the manufactured molten chemical salt into a core mold and solidifying the molten chemical salt to manufacture a core.   
     
     
         2 . The method for manufacturing a soluble core for high pressure casting according to  claim 1 ,
 wherein the water-soluble chemical salt mixture includes any one or more selected from the group consisting of a chloride-based chemical salt, a carbide-based chemical salt, and a sulfide-based chemical salt.   
     
     
         3 . The method for manufacturing a soluble core for high pressure casting according to  claim 2 ,
 wherein the chloride-based chemical salt includes any one or more selected from the group consisting of NaCl, KCl, MnCl 2 , CaCl, MgCl 2 , and LiCl,   the carbide-based chemical salt includes any one or more selected from the group consisting of K 2 CO 3 , Li 2 CO 3  and Na 2 CO 3 , and   the sulfide-based chemical salt includes any one or more selected from the group consisting of K 2 SO 4 , Na 2 SO 4 , and Li 2 SO 4 .   
     
     
         4 . The method for manufacturing a soluble core for high pressure casting according to  claim 2 ,
 wherein the water-soluble chemical salt mixture is selected from the group consisting of water-soluble chemical salt mixtures of KCl:MnCl 2 :NaCl in a ratio of 45.5:33.5:20, CaCl 2 :KCl:MgCl 2 :NaCl in a ratio of 41.6:2.2:8.8:47.4, CrCl 2 :KCl in a ratio of 60:40, K 2 CO 3 :Li 2 CO 3 :Na 2 CO 3  in a ratio of 25:43.5:31.5, K 2 CO 3 :MgCO 3  in a ratio of 55:45, K 2 SO 4 :Li 2 SO 4  in a ratio of 18:82, K 2 SO 4 :Na 2 SO 4  in a ratio of 75:25, LiCl:Li 2 SO 4 :Li 2 CO 3  in a ratio of 52.9:27.2:19.8, LiCl:Li 2 SO 4 :NaCl in a ratio of 54.8:29:16.1, LiCl:Li 2 CO 3 :Li 2 SO 4  in a ratio of 52.9:19.8:27.2, and CaSO 4 :LiCl in a ratio of 14:86, in terms of a mixing ratio (Mol %).   
     
     
         5 . The method for manufacturing a soluble core for high pressure casting according to  claim 1 ,
 wherein the heat-resistant hard powder includes any one or more selected from the group consisting of TiO 2 , Al 2 O 3 , and ZrSiO 4 .   
     
     
         6 . The method for manufacturing a soluble core for high pressure casting according to  claim 1 ,
 wherein the water-soluble chemical salt mixture has a melting point 140° C. to 260° C. lower than a melting point of a cast metal.   
     
     
         7 . The method for manufacturing a soluble core for high pressure casting according to  claim 1 ,
 wherein a cast metal is an aluminum alloy or a magnesium alloy.   
     
     
         8 . The method for manufacturing a soluble core for high pressure casting according to  claim 1 , further comprising:
 a step of installing the manufactured core in a high pressure casting mold, performing high pressure casting of a molten metal, and then performing heating to a temperature equal to or less than the melting point of the cast alloy to extract the molten core.   
     
     
         9 . A soluble core for high pressure casting formed of a molten chemical salt having a heat capacity of 90 J/(mol·K) or more obtained by uniformly dispersing and mixing a heat-resistant hard powder into a water-soluble chemical salt mixture having a melting point 140° C. to 260° C. lower than a melting point of a cast metal, which includes any one or more selected from the group consisting of a chloride-based chemical salt, a carbide-based chemical salt, and a sulfide-based chemical salt. 
     
     
         10 . The soluble core for high pressure casting according to  claim 9 ,
 wherein the chloride-based chemical salt includes any one or more selected from the group consisting of NaCl, KCl, MnCl 2 , CaCl, MgCl 2 , and LiCl,   the carbide-based chemical salt includes any one or more selected from the group consisting of K 2 CO 3 , Li 2 CO 3  and Na 2 CO 3 , and   the sulfide-based chemical salt includes any one or more selected from the group consisting of K 2 SO 4 , Na 2 SO 4 , and Li 2 SO 4 .   
     
     
         11 . The soluble core for high pressure casting according to  claim 9 ,
 wherein the water-soluble chemical salt is selected from the group consisting of water-soluble chemical salt mixtures of KCl:MnCl 2 :NaCl in a ratio of 45.5:33.5:20, CaCl 2 :KCl:MgCl 2 :NaCl in a ratio of 41.6:2.2:8.8:47.4, CrCl 2 :KCl in a ratio of 60:40, K 2 CO 3 :Li 2 CO 3 :Na 2 CO 3  in a ratio of 25:43.5:31.5, K 2 CO 3 :MgCO 3  in a ratio of 55:45, K 2 SO 4 :Li 2 SO 4  in a ratio of 18:82, K 2 SO 4 :Na 2 SO 4  in a ratio of 75:25, LiCl:Li 2 SO 4 :Li 2 CO 3  in a ratio of 52.9:27.2:19.8, LiCl:Li 2 SO 4 :NaCl in a ratio of 54.8:29:16.1, LiCl:Li 2 CO 3 :Li 2 SO 4  in a ratio of 52.9:19.8:27.2, and CaSO 4 :LiCl in a ratio of 14:86, in terms of a mixing ratio (Mol %).   
     
     
         12 . A method for extracting a soluble core for high pressure casting,
 wherein the soluble core for high pressure casting according to  claim 9  is heated to a temperature equal to or less than the melting point of a product after high pressure casting, melted, extracted, and then washed with water.