초록 ▼

A method (20) of fabricating a large component such as a gas turbine or compressor disk (32) from segregation-prone materials such as Alloy 706 or Alloy 718 when the size of the ingot required is larger than the size that can be predictably formed without segregations using known triple melt process

A method (20) of fabricating a large component such as a gas turbine or compressor disk (32) from segregation-prone materials such as Alloy 706 or Alloy 718 when the size of the ingot required is larger than the size that can be predictably formed without segregations using known triple melt processes. A sound inner core ingot (12) is formed (22) to a first diameter (D1), such as by using a triple melt process including vacuum induction melting (VIM), electroslag remelting (ESR), and vacuum arc remelting (VAR). Material is than added (26) to the outer surface (16) of the core ingot to increase its size to a dimension (D2) required for the forging operation (28). A powder metallurgy or spray deposition process may be used to apply the added material. The added material may have properties that are different than those of the core ingot and may be of graded composition across its depth. This process overcomes ingot size limitations for segregation-prone materials.

대표청구항 ▼

The invention claimed is: 1. A method comprising: forming a core ingot of nickel-iron based superalloy material to have a first dimension using a triple melt process comprising vacuum induction melting, electroslag remelting, and vacuum are remelting effective to inhibit segregation defects within

The invention claimed is: 1. A method comprising: forming a core ingot of nickel-iron based superalloy material to have a first dimension using a triple melt process comprising vacuum induction melting, electroslag remelting, and vacuum are remelting effective to inhibit segregation defects within the core ingot; adding material to an outer surface of the core ingot using a second process effective to cause the material to bond to the core ingot and build up on itself to form a final ingot having a second dimension greater than the first dimension, the second process selected from the group consisting of powder metallurgy, metal spray deposition and welding; and forging the final ingot into a desired shape. 2. The method of claim 1, further comprising adding the material to the outer surface of the core ingot using a powder metallurgy process. 3. The method of claim 2, further comprising adding the material to the outer surface of the core ingot using a metal spray deposition process. 4. The method of claim 2, further comprising adding the material to the outer surface of the core ingot using a welding process. 5. The method of claim 1, further comprising: forming the core ingot of a first material; and adding a second material different than the first material to the outer surface of the core ingot. 6. The method of claim 1, further comprising: forming the core ingot of Alloy 706 material; and adding Alloy 718 as the added material to the outer surface of the core ingot. 7. The method of claim 1, further comprising the added material having a graded property across its depth to the outer surface of the core ingot. 8. The method of claim 1, wherein the triple melt process is completed before the second process is completed. 9. The method of claim 8, wherein the triple melt process is completed before the second process is begun. 10. The method of claim 1, wherein the added material builds up on itself via a continual application of added material particles over a period of time. 11. The method of claim 1, wherein the final ingot has a segregation defect inhibiting diameter greater than 30 inches. 12. A method of forming an ingot having a dimension that exceeds a first dimension at which a triple melt process will predictably produce a segregation-free metallurgy using a segregation-prone material, the method comprising: forming a core ingot to no more than the first dimension using a triple melt process effective to inhibit segregation defects within the core ingot; and adding material to an outer surface of the core ingot using a second process effective to cause the material to bond to the core ingot and different than the triple melt process to form a final ingot having a second dimension larger than the first dimension. 13. The method of claim 12, further comprising forming the core ingot of one of Alloy 706 and Alloy 718 material. 14. The method of claim 12, further comprising adding the material to the outer surface of the core ingot using a powder metallurgy process. 15. The method of claim 12, further comprising adding the material to the outer surface of the core ingot using a metal spray deposition process. 16. The method of claim 12, further comprising the added material being different than the material of the core ingot to the outer surface of the core ingot. 17. The method of claim 12, further comprising the added material being graded in composition across its depth to the outer surface of the core ingot. 18. The method of claim 12, wherein the triple melt process is completed before the second process is completed. 19. The method of claim 12, wherein the second process is effective to cause the material to bond to the core ingot and build up on itself. 20. The method of claim 19, wherein, the second process is selected from the group consisting of powder metallurgy, metal spray deposition and welding.