Mold for air-slip type noncircular continuous casting and casting method of aluminum alloy using the same

Abstract

The present invention relates to a mold for air-slip noncircular continuous casting and a casting method of aluminum alloy using the same. The mold of the present invention includes a mold body 20 having a noncircular through hole 10 which allows molten metal 80 to move therein; a porous graphite ring 70 provided on an inner circumference of the mold body 20 to supply gas and oil to a surface of the lowering molten metal 80 metal thereby solidifying the molten metal 80 into a billet; and a conveying plate 95 provided on the inner circumference of the mold body 20 on top of the graphite ring 70 to convey the molten metal 80 downward, wherein a cooling water chamber 60 is formed in the mold body 20 to store cooling water for cooling a surface of the billet, the cooling water chamber 60 being formed in the rear of the graphite ring 70 , and a gas inlet 32 and an oil inlet 34 are connected to an upper end of the graphite ring 70 to respectively supply gas and oil into the graphite ring 70 through the mold body 20 . According to the present invention so configured, it is possible to enhance durability of the mold and allow production of an aluminum alloy with uniform composition when casting an aluminum alloy with a noncircular cross section.

1 . A mold for air-slip type noncircular continuous casting, comprising:
 a mold body having a noncircular through hole, the noncircular through hole allowing molten metal to move therein;   a porous graphite ring provided on an inner circumference of the mold body to supply gas and oil to a surface of the lowering molten metal thereby solidifying the molten metal into a billet; and   a conveying plate provided on the inner circumference of the mold body on top of the graphite ring to convey the molten metal downward,   wherein a cooling water chamber is formed in the mold body to store cooling water for cooling a surface of the billet, the cooling water chamber being formed in the rear of the graphite ring, and a gas inlet and an oil inlet are connected to an upper end of the graphite ring to respectively supply gas and oil into the graphite ring through the mold is body.   
   
   
       2 . The mold as claimed in  claim 1 , wherein the cooling water chamber is formed such that an upper end of the graphite ring is higher than a lower end of the cooling water chamber and a lower end of the graphite ring is lower than an upper end of the cooling water chamber. 
   
   
       3 . The mold as claimed in  claim 1 , wherein the cooling water chamber is formed such that an upper end of the graphite ring is lower than an upper end of the cooling water chamber and a lower end of the graphite ring is higher than a lower end of the cooling water chamber. 
   
   
       4 . The mold as claimed in any one of  claims 1  to  3 , wherein the mold body includes:
 an upper body defining an upper portion of the chamber and having a lower surface supporting an upper surface of the graphite ring, the upper body being formed with a gas inlet and an oil inlet for respectively supplying gas and oil to an upper portion of the graphite ring;   a lower body defining a lower portion and an outer side portion of the mold body; and   an inner body coupled with the upper body and the lower body to define an inner side of the mold body and having a seat portion formed on an inner circumference thereof to allow the graphite ring to be seated thereon.   
   
   
       5 . The mold as claimed in  claim 4 , wherein the graphite ring has an upper surface supported by the upper body and side and lower surfaces seated on the seat portion of the inner body and fixed to the mold body. 
   
   
       6 . The mold as claimed in  claim 5 , wherein an asbestos gasket is provided between the graphite ring and the upper body. 
   
   
       7 . The mold as claimed in  claim 6 , wherein the graphite ring is divided into a plurality of pieces. 
   
   
       8 . The mold as claimed in  claim 7 , wherein an inner circumference of the graphite ring has a tapered shape whose width is widened as it goes downward to cope with the changed amount of billet that is changed by solidification contraction. 
   
   
       9 . The mold as claimed in  claim 8 , wherein the lower body has cooling water discharge channels for supplying the cooling water of the cooling water chamber to the billet. 
   
   
       10 . The mold as claimed in  claim 9 , wherein the cooling water discharge channels are formed to have different diameters depending on the amount of heat generated from the billet. 
   
   
       11 . The mold as claimed in  claim 9 , wherein the cooling water discharge channels are formed to have different densities at every portion of the inner body depending on the amount of heat generated from the billet. 
   
   
       12 . An air-slip type continuous casting method of aluminum alloy, in which molten metal is solidified while passing through an inner surface of a conveying plate and a graphite ring, thereby producing a billet with a noncircular cross section, the conveying plate and the graphite ring having a tapered shape and being installed on an inner surface of a noncircular through hole of a mold body, the method comprising the steps of:
 forming a film on a surface of the molten metal being solidified by gas and oil introduced from an upper portion of the graphite ring;   cooling the graphite ring by cooling water of a cooling water chamber provided in the rear of the graphite ring; and   allowing a borderline of the solidified billet and the molten metal to be in contact with an inner surface of the graphite ring.   
   
   
       13 . The method as claimed in  claim 12 , wherein the billet is cooled by the cooling water, the cooling water being supplied from the cooling water chamber and ejected through cooling water discharge channels in a lower portion of the graphite ring. 
   
   
       14 . The method as claimed in  claim 13 , wherein the cooling water is ejected in different amounts depending on the amount of heat generated according to a shape of the billet to be cast. 
   
   
       15 . The method as claimed in  claim 14 , wherein the amount of the cooling water is determined by the number of the cooling water discharge channels. 
   
   
       16 . The method as claimed in  claim 14 , wherein the amount of the cooling water is determined by size of the cooling water discharge channels.