Casting process

Abstract

A foundry casting system and process employs an inert gas delivery and recovery system for casting parts which results in cast parts having improved metalurgical characteristics. The system may be employed in sand, die casting, semi-permanent and permanent casting environments. Pressurized inert gas may be diffused into the mold before, during and after the metal pouring step. The resulting casting is free from oxides and dissolved hydrogen gas as they are removed from the mold cavity. This results in higher quality castings as well as increased production output due to faster cooling cycles.

1 - 20 . (canceled) 
     
     
         21 . A casting with a dendrite arm structure (DAS) which is less than 30 microns, prepared by a foundry casting process comprising the steps of:
 providing at least one mold;   connecting an inert gas to the mold;   delivering inert gas to the mold;   flushing mold with inert gas;   delivering molten metal to the mold to form a casting;   stop delivering metal to the mold; and   removing casting from mold, the casting having an inner surface and an outer surface.   
     
     
         22 . The casting as claimed in  claim 21 , further comprising a step of continuously delivering inert gas to the mold during the delivering molten metal to the mold step. 
     
     
         23 . The casting as claimed in  claim 21 , further comprising a step of continuously delivering inert gas to the mold up until the step of removing casting from mold. 
     
     
         24 . The casting as claimed in  claim 21 , wherein the inert gas is one of helium, argon, or nitrogen. 
     
     
         25 . The casting as claimed in  claim 21 , Wherein the dendrite arm structure (DAS) of the casting is in the range of 16 microns to 25 microns. 
     
     
         26 . The casting as claimed in  claim 21 , wherein a percent of elongation of the casting is in a range of 10 to 14. 
     
     
         27 . The casting as claimed in  claim 21 , further comprising the step of applying pressurized inert gas to at least one surface of a casting. 
     
     
         28 . The casting as claimed in  claim 21 , further comprising the step of impinging inert gas at different pressure levels to different surfaces of the casting. 
     
     
         29 . The casting as claimed in  claim 21 , further comprising a dendrite arm structure (DAS) in one area of the casting that is different than another area of the casting. 
     
     
         30 . The casting as claimed in  claim 21 , wherein the flushing step provides inert gas at a rate of about 10 liters per minute for a period of about 10 seconds. 
     
     
         31 . The casting as claimed in  claim 21 , wherein the step of delivering inert gas includes varying a flow rate of inert gas during the casting process. 
     
     
         32 . A foundry casting process of making a casting using inert gas to purge and aid in the solidification of a casting, the process comprising the steps of:
 providing a mold for use with casting a metal part;   connecting an inert gas to the mold;   flushing the mold with inert gas to purge the mold of impurities and to create an O2-free area inside of the mold;   delivering molten metal into the O2-free area inside of the mold;   stopping the flow of molten metal;   continuing to deliver inert gas to the mold during solidification of the molten metal;   stopping the supply of inert gas to the mold; and   removing the metal part from the mold.   
     
     
         33 . The product of the process of  claim 32 . 
     
     
         34 . The product of the process of chin herein the product has a property of a dendrite arm structure (DAS) of less than 30 microns. 
     
     
         35 . The product of the process of  claim 32 , wherein the product has a property of a percent of elongation in a range of 10 to 14. 
     
     
         36 . The process of  claim 32 , further comprising the step of sensing when the molten metal has solidified. 
     
     
         37 . A foundry casting process for manufacture of a casting which comprises:
 providing at least one mold and a fixture;   loading the mold into the fixture;   transferring the fixture to a mold station;   before or after the transferring step, flushing the mold with an inert gas to create an area within the mold that is O2-free;   injecting molten metal into the mold while continuously delivering inert gas to the mold;   stop filling mold when mold is full; and   removing fixture from mold station.   
     
     
         38 . A casting manufactured by the process of  claim 37 . 
     
     
         39 . A casting manufactured by the process of  claim 37 , wherein the casting has a dendrite arm structure (DAS) property that is the range of 16 microns to 25 microns. 
     
     
         40 . A casting manufactured by the process of  claim 37 , wherein the casting has a yield strength that is in the range of 89 Mpa to 92 Mpa.