ISOTHERMAL STRUCTURAL REPAIR OF SUPERALLOY COMPONENTS INCLUDING TURBINE BLADES

• US 20130115092A1
• Filed: 03/08/2012
• Published: 05/09/2013
• Est. Priority Date: 11/03/2011
• Status: Active Grant

• Current Assignee: Siemens Energy Incorporated (Siemens AG)
• Original Assignee: Siemens Energy Incorporated (Siemens AG)
• Inventors: Ozbaysal, Kazim
• Granted Patent: US 9,174,314 B2
• Time in Patent Office: Days
• US Class Current: 416/223.R
• CPC Class Codes: B22D 19/10 Repairing defective or damaged objects by metal casting procedures by other procedures B23P6/04; ingot mould B22D7/06; B22D19/06 takes precedence
• CPC Class Codes: B23K 2101/001 Turbines
• CPC Class Codes: B23K 35/3033 Ni as the principal constituent
• CPC Class Codes: B23P 6/007 using only additive methods, e.g. build-up welding
• CPC Class Codes: B23P 6/045 of turbine components, e.g. moving or stationary blades, rotors, etc.
• CPC Class Codes: F01D 5/005 Repairing methods or devices
• CPC Class Codes: F05D 2230/80 Repairing, retrofitting or upgrading methods
• CPC Class Codes: Y02T 50/60 Efficient propulsion technologies, e.g. for aircraft
• CPC Class Codes: Y10T 428/12639 Adjacent, identical composition, components

Abstract

Structural repair of cracks and other defects in superalloy components, such as steam or gas turbine blades in stationary or aero gas turbines, are performed by heating the blade substrate to an isothermal hold temperature below the substrate'"'"'s incipient melting point and filling the crack with molten superalloy filler material. The molten filler solidifies into a casting and bonds with the component substrate at the isothermal hold temperature. Heat treatment processes are completed, so that the former crack is filled with cast superalloy material having identical or similar structural properties as the adjoining substrate superalloy material. The casting repair method may be utilized universally for all types of superalloy component defects, including those previously repaired by cosmetic, lower strength welding or brazing methods.

Claims

1. A repaired superalloy component comprising a superalloy substrate having a crack therein, wherein said crack is filled with a cast in place patch of filler superalloy selected from the group consisting of the identical superalloy as that of said superalloy component substrate and other superalloys having comparable structural properties.

2. The component of claim 1, wherein the substrate and filler superalloys are indentical.

3. The component of claim 2, wherein the substrate and filler superalloys are selected from the group consisting of CM247 or DS247 superalloys.

4. The component of claim 1, wherein the component is a turbine blade.

5. The component of claim 4, wherein the substrate and filler superalloys are selected from the group consisting of CM247 or DS247 superalloys.

6. The component of claim 1, wherein the patch comprises a plurality of layers of filler superalloy.

7. The component of claim 1, wherein the patch defines an outer surface that conforms with an outer surface of the substrate that adjoins the patch.

8. A repaired superalloy component comprising a superalloy component substrate having a crack therein, wherein said crack is filled with a cast in place patch of filler superalloy selected from the group consisting of the identical superalloy as the superalloy component substrate and other superalloys having comparable structural properties, the cast in place patch formed by the process of:

heating the superalloy component substrate to a desired isothermal hold temperature in a range of between above 800°

C. (1472°

F.) and below said substrate'"'"'s incipient melting point;

filling the crack at the isothermal hold temperature at least partially with molten superalloy filler; and

solidifying the cast superalloy filler to form a patch that is bonded to the superalloy component substrate.

9. The component of claim 8, wherein the substrate and filler superalloys are identical.

10. The component of claim 9, wherein the substrate and filler superalloys are selected from the group consisting of CM247 or DS247 superalloys.

11. The component of claim 8, wherein the component is a turbine blade.

12. The component of claim 11, wherein the substrate and filler superalloys are CM247 superalloy.

13. The component of claim 8, wherein the heating, filling and solidifying steps are performed in a protected atmosphere environment selected from the group consisting of a vacuum and an inert gas atmosphere.

14. The component of claim 8 wherein the filling step is performed by depositing a plurality of sequential layers of molten superalloy filler.

15. The component of claim 8, further comprising heat treating the component substrate and patch.

16. A method for repairing a cracked superalloy component, comprising:

providing a superalloy component with a substrate region having a crack therein;

heating the substrate region to a desired isothermal hold temperature above 800°

C.;

isothermally filling the crack at least partially with molten superalloy filler; and

solidifying the cast superalloy filler to form a patch.

17. The component of claim 16, wherein the heating step is performed in an oven under a protective inert gas atmosphere.

18. The component of claim 16, wherein the filling step is performed by depositing a plurality of sequential layers of molten superalloy filler, including filling thereby any filler cracks appearing in previously deposited superalloy filler.

19. The component of claim 16, wherein the heating, filling and solidifying steps are performed in a vacuum.

20. The component of claim 16, further comprising heat treating the component substrate and patch after the solidifying step.