Process for producing cast item

Abstract

A casting process that employs a collapse-prone core is disclosed. The process includes the steps of mixing one or more kind of an aggregate granular material, one or more kind of a water-soluble binder, and water, to form a mixture of the aggregate granular material, and stirring the mixture to cause it to foam. Such a mixture prevents the generation of undesirable gases when molding a mold and pouring molten metal into the mold. The process also includes the steps of charging the foamed mixture into a molding space, evaporating the moisture within the charged mixture to harden the charged mixture to mold a mold with the hardened mixture, assembling at least one mold that is cast in the hardened mixture with the mating mold to form a completed mold, pouring molten metal into the completed mold, removing the completed mold from a cast article that is composed of the solidified molten metal during a process of cooling the cast article after the molten metal is solidified, and applying a heat treatment to the cast article.

1 . A casting process comprising the steps of: 
 mixing one or more kind of an aggregate granular material, one or more kind of a water-soluble binder, and water, to form a mixture of said aggregate granular material, and stirring said mixture to cause it to foam;    charging said foamed mixture into a molding space, and evaporating the moisture within said charged mixture to harden said charged mixture to mold a mold with said hardened mixture;    assembling at least one mold that is cast in said hardened mixture and the mating mold to form a completed mold;    pouring molten metal into said completed mold;    removing said completed mold from a cast article that is composed of the solidified molten metal during a process of cooling said cast article after said molten metal solidifies; and    applying a heat treatment to said cast article.    
   
   
       2 . A casting processes as recited in  claim 1 , wherein said at least one mold that is cast in said hardened mixture is a core, and said mating mold is a master mold.  
   
   
       3 . A casting processes as recited in  claim 2 , wherein said master mold is a metal mold.  
   
   
       4 . A casting processes as recited in  claim 2 , wherein said master mold is a sand mold.  
   
   
       5 . A casting process as recited in any one of the preceding claims, further comprising steps of returning said aggregate granular material, and recovering said returned aggregate granular material.  
   
   
       6 . A casting process as recited in  claim 5 , further comprising steps of recycling and using said returned and recovered aggregate granular material for molding a mold.  
   
   
       7 . A casting process as recited in  claim 5  or  6 , wherein said steps of returning and recovering said aggregate granular material are mechanical recovering processes.  
   
   
       8 . A casting process as recited in any of the preceding claims, wherein said cast article is cast in an aluminum alloy or a magnesium alloy.  
   
   
       9 . A casting process as recited in  claim 8 , wherein said heat treatment is a T6 treatment or a T7 treatment.  
   
   
       10 . A casting process as recited in any one of claims  1 - 7 , wherein said cast article is cast in a casting iron, a casting steel, or a ferrous alloy.  
   
   
       11 . A casting process as recited in any one of claims  1 - 7 , wherein said cast article is cast in a copper alloy.  
   
   
       12 . A casting process as recited in any one of claims  1 - 7 , wherein said step of removing said completed mold from said cast article is to apply shakes in said mold.  
   
   
       13 . A casting process as recited in any one of claims  1 - 7 , wherein said step of applying said shakes in said mold includes impact forces of less than 1 MPa at an operating frequency at less than 30 Hz being applied in said mold for less than 30 seconds, within from 5 to 20 minutes after said molten metal is poured.  
   
   
       14 . A casting process comprising the steps of 
 mixing one or more kind of aggregate granular material, one or more kind of a water-soluble binder, and water, to form a mixture of said aggregate granular material, and stirring said mixture to cause it to foam;    charging said foamed mixture into a molding space, and evaporating the moisture within said charged mixture to harden said charged mixture to mold a core with said hardened mixture;    assembling at least one core that is cast in said hardened mixture and a metal mold to form a completed mold;    pouring a molten aluminum alloy into said completed mold;    removing said core from a cast article that is composed of the solidified molten aluminum alloy during a cooling process of said cast article after said molten metal is solidified; and    applying the T6 or T7 heat treatment to said cast article that is cast in said aluminum alloy.    
   
   
       15 . A casting process as recited in any of claims  1 - 14 , wherein said one or more kind of said water-soluble binder is at least either a polyvinyl alcohol or its derivative, or at least either a starch or its derivative.