Double casting method and apparatus

Abstract

The present invention relates to a duplex casting apparatus and a duplex casting method. The duplex casting apparatus includes a casting chamber in which a space portion is formed; an injection tube mounted below the casting chamber and into which a molten metal is injected; a mold detachably connected to the injection tube and having a cavity; a filling medium filled between an inner portion of the casting chamber and the mold; and a pressure regulation means disposed above the casting chamber and decompressing the inner portion of the casting chamber.

1 . A duplex casting apparatus comprising:
 a casting chamber in which a space portion is formed;   an injection tube mounted below the casting chamber and into which a molten metal is injected;   a mold detachably connected to the injection tube and having a cavity;   a filling medium filled between an inner portion of the casting chamber and the mold; and   a pressure regulation means disposed above the casting chamber and configured to decompress the inner portion of the casting chamber.   
     
     
         2 . The duplex casting apparatus according to  claim 1 , further comprising a riser configured to accommodate the molten metal by coming in communication with an upper portion of the cavity in the mold and discharge the molten metal to the cavity. 
     
     
         3 . The duplex casting apparatus according to  claim 1 , wherein the riser is formed in a size of about 30 volume % to about 120 volume % of the mold. 
     
     
         4 . The duplex casting apparatus according to  claim 1 , further comprising a melting furnace configured to melt a raw material to form a molten metal. 
     
     
         5 . The duplex casting apparatus according to  claim 1 , wherein an inner diameter of the injection tube is larger than an inner diameter of an inlet of the cavity. 
     
     
         6 . The duplex casting apparatus according to  claim 5 , wherein a ratio of the inner diameter of the cavity to the inner diameter of the injection tube is about 1:1.1 to about 1:3. 
     
     
         7 . The duplex casting apparatus according to  claim 1 , wherein the pressure regulation means comprises a suction screen, a vacuum pump, and a suction tube. 
     
     
         8 . A duplex casting method comprising:
 decompressing the casting chamber into which the filling medium is filled by the pressure regulation means and performing first injection of a molten metal into the cavity inside the mold along the injection tube by the pressure difference with the outside; and   undoing the decompression of the casting chamber before the molten metal of the first injection into the cavity is coagulated and performing second injection of the molten metal by gravity.   
     
     
         9 . The duplex casting method according to  claim 8 , wherein:
 the molten metal is also injected into the riser formed to come in communication with the upper portion of the cavity in the mold in the first injection; and   the molten metal injected into the riser is discharged by gravity and the second injection into the cavity is performed when the decompression of the casting chamber is undone.   
     
     
         10 . The duplex casting method according to  claim 8 , further comprising inserting the mold into the casting chamber on which the injection tube is mounted to be coupled to the injection tube, and performing the first injection of the molten metal by decompression after filling the inner portion of the casting chamber with the filling medium. 
     
     
         11 . The duplex casting method according to  claim 8 , wherein a decompression rate of the casting chamber is regulated to regulate a speed at which the molten metal is injected into the mold. 
     
     
         12 . The duplex casting method according to  claim 8 , wherein the injection tube, the pressure regulation means, and the filling medium are reused.