SPLICE INSERT REPAIR FOR SUPERALLOY TURBINE BLADES

• US 20130115091A1
• Filed: 01/25/2012
• Published: 05/09/2013
• Est. Priority Date: 11/04/2011
• Status: Active Grant

• Current Assignee: Siemens Energy Incorporated (Siemens AG)
• Original Assignee: Siemens Energy Incorporated (Siemens AG)
• Inventors: Bruck, Gerald J., Shinn, Brandon W.
• Granted Patent: US 9,057,271 B2
• Time in Patent Office: Days
• US Class Current: 416/223.R
• CPC Class Codes: B23K 1/0018 Brazing of turbine parts
• CPC Class Codes: B23P 6/005 using only replacement pieces of a particular form
• CPC Class Codes: F01D 5/005 Repairing methods or devices
• CPC Class Codes: F05D 2230/80 Repairing, retrofitting or upgrading methods
• CPC Class Codes: Y10T 29/49318 Repairing or disassembling

Abstract

A damaged portion of a superalloy material turbine blade body is removed, forming an excavated recess. A repair splice is formed of a same material with similar mechanical structural properties, having a mating outer profile conforming to the corresponding recess profile. The repair splice is inserted and captured within the recess, so that the blade body and repair splice are mechanically interlocked. Given similarities in mechanical properties of both the blade body and the mechanically interlocked splice the repaired blade'"'"'s overall mechanical structural properties are similar to those of an undamaged blade. The repair splice is affixed to the blade body so that the interlocking respective portions of each do not separate. Localized affixation and subsequent cosmetic blade surface repair can be performed with softer, low temperature application braze and weld alloys.

Claims

1. A repaired turbine blade comprising a blade body having an excavated recess and a mating, mechanically interlocking repair splice inserted and captured within the recess, with the repair splice affixed to the blade body for retention thereof.

2. The repaired turbine blade of claim 1, wherein the recess and repair splice have mating profiles that locally vary, and only allow unidirectional insertion and withdrawal of the repair splice.

3. The repaired turbine blade of claim 1, wherein the recess comprises at least one through-slot passing fully through the blade body.

4. The repaired turbine blade of claim 3, wherein the through-slot cross-sectional profile locally varies and allows only unidirectional insertion and withdrawal of the mating repair splice.

5. The repaired turbine blade of claim 3, wherein the through-slot and repair splice are planar.

6. The repaired turbine blade of claim 1, wherein the recess comprises a blind recess formed partially within the blade body thickness for engagement with a mating projecting portion formed in the repair splice.

7. The repaired turbine blade of claim 1, wherein the turbine blade body defines a hollow portion and the recess has a profile that facilitates unidirectional repair splice insertion from inside the hollow portion toward an exterior surface of the blade.

8. The repaired turbine blade of claim 1, wherein the repair splice forms at least a portion of a turbine blade end cap.

9. The repaired turbine blade of claim 1, wherein the blade body and repair splice are constructed of a same material with substantially similar mechanical structural properties, affixed to each other with heat-applied alloys selected from the group consisting of brazing alloys and weld alloys that upon their application do not substantially change said structural properties.

10. A method for repairing a turbine blade comprising:

removing a damaged portion of a body of a turbine blade and forming an excavated recess therein whose profile is defined by the blade body;

forming a repair splice having a mating outer profile corresponding to the recess profile;

inserting and capturing the repair splice within the recess, so that the blade body and repair splice are mechanically interlocking after said insertion; and

affixing the repair splice to the blade body in order to prevent their separation.

11. The method of claim 10, wherein the removing step is performed by electric discharge machining.

12. The method of claim 10, wherein the blade body and repair splice are constructed of a same material with substantially similar mechanical structural properties;

and the affixing step is performed by heat application of alloys selected from the group consisting of brazing alloys and weld alloys that upon their application do not substantially change said structural properties.

13. The method of claim 10, wherein during the removing and forming steps the recess and repair splice mating profiles so formed only allow unidirectional insertion and withdrawal of the repair splice.

14. The method of claim 10, wherein during the removing step the recess so formed comprises at least one through-slot passing fully through the blade body.

15. The method of claim 10, wherein during the removing step the recess so formed comprises a through-slot whose cross-sectional profile locally varies and allows only unidirectional insertion and withdrawal of the mating repair splice.

16. The method of claim 10, wherein during the removing and forming steps the recess and repair splice mating profiles so formed are planar.

17. The method of claim 10, wherein during the removing step the recess so formed comprises a blind recess formed partially within the blade body thickness for engagement with a mating projecting portion formed in the repair splice.

18. The method of claim 10, wherein the turbine blade body defines a hollow portion and during the removing step the recess so formed has a profile that facilitates unidirectional repair splice insertion from inside the hollow portion toward an exterior surface of the blade.

19. The method of claim 10, wherein during the forming step the repair splice forms at least a portion of a turbine blade end cap.

20. A method for repairing a turbine blade end cap, comprising:

removing a damaged portion of a turbine blade end cap and forming an excavated recess whose profile is defined by the remaining undamaged end cap and blade body;

forming an end cap repair splice having a mating outer profile corresponding to the recess profile, wherein repair splice is constructed of a same material as the blade body with substantially similar mechanical structural properties;

inserting and capturing the repair splice within the recess, so that the undamaged end cap and blade body and end cap repair splice are mechanically interlocking after said insertion;

affixing the end cap repair splice to the undamaged end cap and blade body, in order to prevent their separation, by heat application of alloys selected from the group consisting of brazing alloys and weld alloys that upon their application do not substantially change said structural properties; and

cosmetically filling any separation gaps between the mating blade body surfaces defining the recess and the repair splice.