Investment casting

• US 7,201,212 B2
• Filed: 08/28/2003
• Issued: 04/10/2007
• Est. Priority Date: 08/28/2003
• Status: Expired due to Term

• Current Assignee: Rtx Corporation
• Original Assignee: United Technologies Corporation (Raytheon Technologies Corporation d/b/a RTX)
• Inventors: Bullied, Steven J., Murray, Stephen D., Herring, Maria A., Krotzer, W. Samuel Jr.
• Primary Examiner(s): Lin; Kuang Y.
• Application Number:
  US10/652,643
• Publication Number:
  US 20050045301A1
• Time in Patent Office: 1,321 Days
• Field of Search: 164/122.1, 164/122.2, 164/516, 164/137, 164339-341
• US Class Current: 164/516
• CPC Class Codes: B22C 9/04 Use of lost patterns
• CPC Class Codes: B22C 9/08 Features with respect to supply of molten metal, e.g. ingates, circular gates, skim gates

Abstract

A method and apparatus are used to cast a number of elements such as turbine engine blades. The blades have an airfoil and a root for securing the blade to a disk. A number of mold sections each have internal surfaces for forming an associated at least one of the elements. The mold sections are assembled and molten alloy is introduced to the assembled mold sections.

Claims

1. A method for casting a plurality of blades having an airfoil and a root for securing the blade to a separate disk wherein each of the plurality of blades is formed as a separate casting, the method comprising:

forming a plurality of mold sections each having internal surfaces for forming an associated at least one blade of the plurality of blades and for forming an associated feeding passageway;

assembling the plurality of mold sections;

assembling the plurality of mold sections with a single distribution manifold having a plurality of feeder conduits so that each feeder conduit mates with an inlet of an associated one of the feeding passageways; and

introducing a molten alloy to the assembled mold sections.

2. The method of claim 1 wherein:

the molten alloy is simultaneously introduced to the assembled mold sections.

3. The method of claim 1 wherein:

each of the mold sections has the internal surfaces for forming only a single such associated blade; and

the internal surfaces of each of the mold sections include first surfaces for forming an exterior of the associated blade and second surfaces for forming an interior of the associated blade.

4. The method of claim 1 wherein:

the molten alloy is introduced so as to settle to an upper level below a lower extreme of flow path portions through the manifold.

5. The method of claim 1 wherein:

the distribution manifold comprises a manifold body having;

a pour chamber for receiving molten material; and

said plurality of feeder conduits, each extending from the pour chamber to the associated feeding passageway; and

the assembling comprises positioning each of a plurality of filters in an associated one of the feeder conduits.

6. The method of claim 1 wherein the forming of each of the mold sections comprises:

assembling a sacrificial blade pattern and a sacrificial gate form atop a plate;

applying a shell to the assembled blade pattern and gate form; and

heating the shell to melt at least a portion of each of the blade pattern and gate form.

7. The method of claim 1 wherein:

the mold sections are assembled atop a chill plate.

8. The method of claim 1 wherein:

said internal surfaces of each of the mold sections form a mold cavity having a portion for forming the root of the associated blade.

9. The method of claim 8 further comprising:

cooling the molten alloy; and

cutting away casting portions formed above the blade roots.

10. The method of claim 1 further comprising:

removing the distribution manifold;

individually removing the filled mold sections.

11. The method of claim 10 further comprising:

mechanically and/or chemically removing the mold sections from associated castings after said individually removing.

12. The method of claim 1 further comprising:

cooling the molten alloy to leave an associated casting in a blade forming cavity and feeding passageway of each mold section.

13. The method of claim 1 further comprising:

cooling the molten alloy to leave an associated casting in a blade forming cavity and feeding passageway of each mold section, the casting not extending into the distribution manifold.

14. A method for casting parts comprising:

forming a plurality of mold sections, each section having internal surfaces defining a mold cavity for forming one or more separate ones of said parts;

assembling a cluster of the mold sections so that the internal surface forming each mold cavity is separate from the others; and

assembling a distribution manifold to the cluster, the distribution manifold having;

a pour chamber for receiving molten material; and

a plurality of feeder conduits, each extending from the pour chamber toward an associated one or more of the assembled mold sections.

15. The method of claim 14 further comprising:

inspecting the mold sections and wherein the cluster is assembled from mold sections that have passed such inspection.

16. The method of claim 15 further comprising:

discarding one or more of the mold sections that have failed such inspection.

17. The method of claim 14 further comprising:

pouring the molten material into the pour chamber; and

in a furnace, disassembling the manifold from the cluster and disassembling the cluster.

18. The method of claim 14 further comprising:

pouring the molten material into the pour chamber; and

permitting the molten material to solidify to consist essentially of a nickel- or cobalt-based superalloy.

19. A mold assembly comprising:

a plurality of mold sections, wherein each section has internal surfaces forming a mold cavity separate from the others; and

a separately formed distribution manifold assembled to the plurality of mold sections and having;

a single pour chamber in a first portion of the manifold for receiving molten material;

a plurality of feeder conduits, each formed in a branch portion of the manifold, unitarily formed as a common piece with the first portion and extending from the pour chamber toward an associated one or more of the plurality of mold sections; and

a plurality of filters, each positioned in an associated one of the feeder conduits.

20. The mold assembly of claim 19 wherein:

there are exactly three or exactly four such mold sections; and

there is a single such feeder conduit associated with each of the mold sections.

21. The mold assembly of claim 19 wherein:

each mold section comprises a molding cavity and a gate, the gate extending from a lower end at the molding cavity to an upper end coupled to the distribution manifold.

22. The mold assembly of claim 19 wherein:

the pour chamber is a centrally located chamber.

23. The mold assembly of claim 19 wherein:

sectional areas of the feeder conduits proximate the filters are dimensioned to provide metering of molten metal from the pour chamber.

24. The mold assembly of claim 19 wherein:

the plurality of mold sections are separate and assembled to the manifold with distal portions of the branch portions extending into upper ends of feeding passageways in the mold sections.

25. A mold assembly for molding a plurality of parts comprising:

a plurality of mold sections, each section having internal surfaces defining a mold cavity for forming one or more separate ones of said parts, wherein each mold cavity is separate from the mold cavities of the other sections; and

a separately formed distribution manifold assembled to the plurality of mold sections and having;

a pour chamber for receiving molten material;

a plurality of feeder conduits, each extending from the pour chamber toward an associated one or more of the plurality of mold sections; and

a plurality of filters, each positioned in an associated one of the feeder conduits.

26. A mold assembly comprising:

a plurality of mold sections, each section having internal surfaces defining a mold cavity for forming one or more separate ones of said parts, wherein each mold cavity is separate from the mold cavities of the other sections; and

a separately formed distribution manifold assembled to the plurality of mold sections and having;

a unitarily-formed body defining;

a single pour chamber for receiving molten material; and

a plurality of feeder conduits, each extending from the pour chamber toward an associated one or more of the plurality of mold sections; and

a plurality of filters, each positioned in an associated one of the feeder conduits.