Countergravity casting apparatus and desulfurization methods

Patent metadata

Field	Value
Publication number	US-11772152-B2
Application number	US-202217866387-A
Country	US
Kind code	B2
Filing date	Jul 15, 2022
Priority date	Oct 27, 2017
Publication date	Oct 3, 2023
Grant date	Oct 3, 2023

Abstract

An apparatus for countergravity casting a metallic material, has: a crucible for holding melted metallic material; a casting chamber for containing a mold; a fill tube capable of extending into the crucible to communicate melted metallic material to the casting chamber; and a gas source coupled to a headspace of the melting vessel to allow the gas source to pressurize the headspace to establish a pressure differential to force the melted metallic material upwardly through the fill tube into the mold. Extraneous sulfur is prevented from entering the molten metal from the surrounding environment.

First claim

What is claimed is:

1. A countergravity casting apparatus comprising:
a melting crucible;
a casting mold;
a flowpath from the melting crucible to the casting mold; and
CaO particles positioned to prevent extraneous sulfur from entering molten metal from a surrounding environment, the CaO particles exposed to a headspace of the melting crucible.

2. The apparatus of claim 1 wherein the CaO particles are powder.

3. The apparatus of claim 2 wherein:
the CaO particles are in trays.

4. The apparatus of claim 1 wherein:
the CaO particles are in trays.

5. The apparatus of claim 1 wherein:
the mold has a cavity shaped to form a gas turbine engine component.

6. The apparatus of claim 1 wherein:
the mold has a cavity shaped to form a gas turbine engine combustor panel.

7. A method for using the apparatus of claim 1 , the method comprising:
melting a nickel-based superalloy in the melting crucible;
disposing the casting mold under subambient pressure on a mold base with a fill tube of said mold extending through an opening in said base;
relatively moving said melting crucible and said base to immerse an opening of said fill tube in the melted nickel-based superalloy in said melting crucible and to engage said melting crucible and said base with seal means therebetween such that a sealed gas pressurizable space is formed between the melted nickel-based superalloy and said base; and
gas pressurizing said space to establish a pressure differential on the melted nickel-based superalloy to force it upwardly through said fill tube into said casting mold.

8. The method of claim 7 wherein:
the CaO particles getter sulfur from the surrounding environment to prevent extraneous sulfur from entering the molten metal from the surrounding environment.

9. The apparatus of claim 2 wherein:
the powder is 50 mesh to 500 mesh powder.

10. An apparatus for countergravity casting a metallic material, the apparatus comprising:
a crucible for holding melted metallic material;
a casting chamber for containing a mold;
a fill tube capable of extending into the crucible to communicate melted metallic material to the casting chamber;
a gas source coupled to a headspace of the melting crucible to allow the gas source to pressurize said headspace to establish a pressure differential to force the melted metallic material upwardly through said fill tube into said mold; and
means for preventing extraneous sulfur from entering the melted metallic material from a surrounding environment.

11. The apparatus of claim 10 wherein:
the means comprises a container of particulate.

12. The apparatus of claim 10 wherein:
the means comprises CaO.

13. The apparatus of claim 10 wherein:
the means comprises pellets.

14. The apparatus of claim 10 wherein:
the means comprises 50 mesh to 500 mesh powder.

15. A method for using the apparatus of claim 10 , the method comprising:
melting a nickel-based superalloy in the melting crucible;
disposing the casting mold under subambient pressure on a mold base with a fill tube of said mold extending through an opening in said base;
relatively moving said melting crucible and said base to immerse an opening of said fill tube in the melted nickel-based superalloy in said melting crucible and to engage said melting crucible and said base with seal means therebetween such that a sealed gas pressurizable space is formed between the melted nickel-based superalloy and said base; and
gas pressurizing said space to establish a pressure differential on the melted nickel-based superalloy to force it upwardly through said fill tube into said casting mold.

16. The method of claim 15 wherein:
the means comprises a container of particulate.

17. The method of claim 16 wherein:
the particulate getters sulfur from the surrounding environment to prevent extraneous sulfur from entering the molten metal from the surrounding environment.

18. The method of claim 17 wherein:
the means comprises CaO.

19. The method of claim 17 wherein:
the means comprises 50 mesh to 500 mesh powder.

20. The method of claim 15 wherein:
the means getters sulfur from the surrounding environment to prevent extraneous sulfur from entering the molten metal from the surrounding environment.

Assignees

• Raytheon Tech Corp
• Rtx Corp

Inventors

• Marcin Jr John J
• Cetel Alan D
• Bochiechio Mario P
• Clemens Reade R

Classifications

• B22D1/00 Primary

  Treatment of fused masses in the ladle or the supply runners before casting {(for continuous casting B22D11/10; metallurgical processing, e.g. refining of iron or other metal C21, C22, C25C)} · CPC title

• B22D1/007

  Treatment of the fused masses in the supply runners (B22D1/002, B22D1/005 take precedence) · CPC title

• B22D18/06

  Vacuum casting, i.e. making use of vacuum to fill the mould · CPC title

• B22D21/025

  Casting heavy metals with high melting point, i.e. 1000 - 1600 degrees C, e.g. Co 1490 degrees C, Ni 1450 degrees C, Mn 1240 degrees C, Cu 1083 degrees C · CPC title

• B22D23/00

  Casting processes not provided for in groups B22D1/00 - B22D21/00 (making metallic powder by casting B22F9/08; alumino-thermic welding B23K23/00; remelting metals C22B9/16) · CPC title