Systems for centrifugally casting highly reactive titanium metals

Abstract

Systems for centrifugally casting a highly reactive titanium metal including a cold wall induction crucible for containing a titanium metal charge, the induction crucible having a plurality of induction coils and a removable bottom plate, a power source to heat the titanium metal charge in the induction crucible to obtain a molten metal, a preheated secondary crucible for catching the molten metal as it falls from the induction crucible after the removable bottom plate has been withdrawn and the power source turned off, and a centrifugal casting machine for holding and accelerating the secondary crucible to centrifugally force the molten metal into a casting mold and produce a cast component.

1 . A system for centrifugally casting a highly reactive titanium metal comprising:
 a cold wall induction crucible for containing a titanium metal charge, the induction crucible having a plurality of induction coils and a removable bottom plate;   a power source to heat the titanium metal charge in the induction crucible to obtain a molten metal;   a preheated secondary crucible for catching the molten metal as it falls from the induction crucible after the removable bottom plate has been withdrawn and the power source turned off, and   a centrifugal casting machine for holding and accelerating the secondary crucible to centrifugally force the molten metal into a casting mold and produce a cast component.   
   
   
       2 . The system of  claim 1  wherein the titanium metal charge comprises a titanium aluminide alloy. 
   
   
       3 . The system of  claim 1  wherein the bottom plate of the induction crucible is withdrawn using a method selected from the group consisting of sliding, rotating and dropping. 
   
   
       4 . The system of  claim 1  wherein the cast component comprises a low pressure turbine blade. 
   
   
       5 . The system of  claim 2  wherein the induction coils of the induction crucible are used to heat the metal charge to a temperature of from about 1480° C. to about 1557° C. to obtain the molten metal. 
   
   
       6 . The system of  claim 1  wherein the molten metal becomes suspended within the induction crucible. 
   
   
       7 . The system of  claim 2  wherein the secondary crucible is heated to a temperature of at least about 1000° C. when the secondary crucible comprises niobium and at least about 1082° C. when the secondary crucible comprises ceramic. 
   
   
       8 . The system of  claim 1  wherein:
 the centrifugal casting machine holds the secondary crucible stationary for from about 0.5 to about 2 seconds after the molten metal falls into the secondary crucible and, thereafter, the centrifugal casting machine accelerates the secondary crucible to from about 100 rpm to about 600 rpm within from about 1 second to about 2 seconds to centrifugally force the molten metal into the casting mold to produce the cast component.   
   
   
       9 . A system for centrifugally casting a highly reactive titanium metal comprising:
 a cold wall induction crucible for containing a titanium metal charge, the induction crucible having a plurality of induction coils and a removable bottom plate;   a power source to heat the titanium metal charge in the induction crucible to obtain a molten metal;   a preheated secondary crucible for catching the molten metal as it falls from the induction crucible after the removable bottom plate has been withdrawn and the power source turned off;   a funnel for transferring the molten metal from the induction crucible to the secondary crucible; and   a centrifugal casting machine for holding and accelerating the secondary crucible to centrifugally force the molten metal into a casting mold and produce a cast component.   
   
   
       10 . The system of  claim 10  wherein the titanium metal charge comprises a titanium aluminide alloy. 
   
   
       11 . The system of  claim 9  wherein the bottom plate of the induction crucible is withdrawn using a method selected from the group consisting of sliding, rotating and dropping. 
   
   
       12 . The system of  claim 10  wherein the cast component comprises a low pressure turbine blade. 
   
   
       13 . The system of  claim 10  wherein the induction coils of the induction crucible are used to heat the metal charge to a temperature of from about 1480° C. to about 1557° C. to obtain the molten metal. 
   
   
       14 . The system of  claim 9  wherein the molten metal becomes suspended within the induction crucible. 
   
   
       15 . The system of  claim 10  wherein the secondary crucible is heated to a temperature of at least about 1000° C. when the secondary crucible comprises niobium and at least about 1082° C. when the secondary crucible comprises ceramic. 
   
   
       16 . The system of  claim 9  wherein:
 the centrifugal casting machine holds the secondary crucible stationary for from about 0.5 to about 2 seconds after the molten metal falls into the secondary crucible and, thereafter, the centrifugal casting machine accelerates the secondary crucible to from about 100 rpm to about 600 rpm within from about 1 second to about 2 seconds to centrifugally force the molten metal into the casting mold to produce the cast component.   
   
   
       17 . A system for centrifugally casting a highly reactive titanium metal comprising:
 a cold wall induction crucible for containing a titanium aluminide charge, the induction crucible having a plurality of induction coils and a slidably removable bottom plate;   a power source to heat the titanium aluminide charge in the induction crucible to obtain a molten titanium aluminide;   a preheated secondary crucible for catching the molten titanium aluminide as it falls from the induction crucible after the removable bottom plate has been withdrawn and the power source turned off;   a niobium funnel for transferring the molten titanium aluminide from the induction crucible to the secondary crucible; and   a centrifugal casting machine for holding the secondary crucible stationary for from about 0.5 to about 2 seconds after the molten titanium aluminide falls into the secondary crucible and, thereafter, accelerating the secondary crucible to from about 100 rpm to about 600 rpm within from about 1 second to about 2 seconds to centrifugally force the molten titanium aluminide into a casting mold and produce a cast component.   
   
   
       18 . The system of  claim 17  wherein the induction coils of the induction crucible are used to heat the metal charge to a temperature of from about 1480° C. to about 1557° C. to obtain the molten metal. 
   
   
       19 . The system of  claim 17  wherein the secondary crucible is heated to a temperature of at least about 1000° C. when the secondary crucible comprises niobium and at least about 1082° C. when the secondary crucible comprises ceramic. 
   
   
       20 . The system of  claim 17  wherein the cast component comprises a low pressure turbine blade.