TURBINE AIRFOIL CASTING METHOD

• US 20090165988A1
• Filed: 12/31/2007
• Published: 07/02/2009
• Est. Priority Date: 12/31/2007
• Status: Abandoned Application

• Current Assignee: General Electric Company
• Original Assignee: General Electric Company
• Inventors: Abbott, David Henry, Rockstroh, Todd Jay, Tewari, Sudhir K., Desander, Donald Brett, Sabato, Joseph Giancarlo, Gledhill, Mark Douglas
• Application Number:
  US11/968,022
• Publication Number:
  US 20090165988A1
• Time in Patent Office: Days
• US Class Current: 164/492
• CPC Class Codes: B22C 9/04 Use of lost patterns
• CPC Class Codes: B22C 9/10 Cores; Manufacture or installation of cores breaker cores B22C9/084
• CPC Class Codes: F01D 5/187 Convection cooling
• CPC Class Codes: F05D 2230/211 by precision casting, e.g. microfusing or investment casting
• CPC Class Codes: F05D 2260/202 by film cooling
• CPC Class Codes: F05D 2260/2212 by creating turbulence

Abstract

A method for making a turbine airfoil includes: (a) providing a mold having: (i) a core; (ii) an outer shell surrounding the core such that the core and the outer shell cooperatively define a cavity in the shape of an airfoil having at least one outer wall; and (iii) a core support extending from the core to the outer shell through a portion of the cavity that defines the at least one sidewall; (b) introducing molten metal alloy into the cavity and surrounding the core support; (c) solidifying the alloy to form an airfoil casting having at least one outer wall which has at least one core support opening passing therethrough; (d) removing the mold so as to expose the airfoil; and (e) sealing the at least one core support opening in the airfoil with a metal alloy metallurgically bonded to the at least one outer wall.

Claims

1. A method for making a turbine airfoil, comprising:

(a) providing a mold having;

(i) a core;

(ii) an outer shell surrounding the core such that the core and the outer shell cooperatively define a cavity in the shape of an airfoil having at least one outer wall; and

(iii) a core support extending from the core to the outer shell through a portion of the cavity that defines the at least one sidewall;

(b) introducing molten metal alloy into the cavity and surrounding the core support;

(c) solidifying the alloy to form an airfoil casting having at least one outer wall which has at least one core support opening passing therethrough;

(d) removing the mold so as to expose the airfoil; and

(e) sealing the at least one core support opening in the airfoil with a metal alloy metallurgically bonded to the at least one outer wall.

2. The method of claim 1 wherein step (e) is carried out by:

(a) melting an alloy power using laser energy;

(b) introducing the melted powder into the at least one core support opening; and

(c) allowing the melted powder to cool and solidify in the at least one core support opening.

3. The method of claim 2 wherein the alloy power has a composition substantially the same as an alloy composition of the airfoil.

4. The method of claim 1 wherein step (e) is carried out by:

(a) introducing an alloy powder into the at least one core support opening;

(b) using laser energy, melting the alloy powder and heating the outer wall; and

(c) allowing the melted powder to cool and solidify in the at least one core support opening.

5. The method of claim 4 wherein the alloy power has a composition substantially the same as an alloy composition of the airfoil.

6. The method of claim 1 wherein the airfoil has a directionally solidified or single crystal microstructure, and the solidified powder in the at least one core support opening has substantially the same microstructure as the airfoil.

7. The method of claim 1 wherein the core support is a cylindrical rod.

8. The method of claim 1 wherein the core support comprises fused quartz.

9. The method of claim 1 wherein the mold comprises:

(i) a core; and

(ii) an outer shell surrounding the core, the outer shell having two spaced-apart sidewalls disposed on opposite sides of the core; and

(iii) a core support extending from the one of the sidewalls of the outer shell, through the core, to the other sidewall of the outer shell.

10. The method of claim 9 wherein the airfoil includes spaced-apart pressure and suction side outer walls each having a core support opening therein, the core support openings being coaxial to each other.

11. The method of claim 1 wherein the mold defines an integral turbine blade including the airfoil and a shank, the airfoil and the shank respectively defining opposite ends of the turbine blade.

12. The method of claim 11 wherein the core support is positioned in the airfoil at an end of the turbine blade opposite from the shank.