Method and device for repairing a damaged blade tip of a turbine blade which is armor-plated and provided with a blade coating

Patent metadata

Field	Value
Publication number	US-11566524-B2
Application number	US-201815884460-A
Country	US
Kind code	B2
Filing date	Jan 31, 2018
Priority date	Feb 2, 2017
Publication date	Jan 31, 2023
Grant date	Jan 31, 2023

Abstract

The invention relates to a method for repairing a damaged blade tip of a turbine blade which is armor-plated and provided with a blade coating, of a thermal gas turbine. The method according to the invention comprises the steps of removing a blade tip armor plating of the turbine blade at least in the region of the damaged blade tip and producing a repair surface ( 12 ), removing only a part of the blade coating of the turbine blade in the region of the repair surface while preserving a part of the blade coating separated from the repair surface ( 14 ), restoring the blade tip reinforcement ( 20 ), and restoring the blade coating in the region of the repaired blade tip ( 22 ). The invention furthermore relates to a device for carrying out such a method.

First claim

What is claimed is:

1. A method for repairing a damaged blade tip of a turbine blade of a thermal gas turbine, which blade is provided with an airfoil coating and with a blade tip armor plating, wherein the method comprises:
removing the blade tip armor plating of the turbine blade at least in a region of the damaged blade tip and producing a repair surface;
removing only a part of the airfoil coating of the turbine blade in a region of the repair surface while preserving a part of the airfoil coating separated from the repair surface;
repairing the damaged blade tip;
restoring the blade tip armor plating; and
restoring the airfoil coating in the region of the repair surface.

2. The method of claim 1 , wherein before restoration of the blade tip armor plating repair material is applied onto the repair surface and a target contour of the blade tip is restored.

3. The method of claim 2 , wherein the target contour of the blade tip is restored by a separating method after application of the repair material.

4. The method of claim 1 , wherein a repair material is applied onto the repair surface by a welding method.

5. The method of claim 4 , wherein the welding method comprises deposit welding.

6. The method of claim 1 , wherein the blade tip armor plating is restored by a joining method.

7. The method of claim 6 , wherein the joining method comprises soldering.

8. The method of claim 1 , wherein the blade tip armor plating is restored by producing and/or applying a particle composite material having embedded hard material particles onto the blade tip.

9. The method of claim 8 , wherein the hard material particles comprise cubic boron nitride (CBN).

10. The method of claim 1 , wherein the airfoil coating is restored by a coating method.

11. The method of claim 10 , wherein the coating method comprises diffusion coating.

12. The method of claim 1 , wherein the blade tip armor plating and/or the airfoil coating is at least partially removed by a separating method.

13. The method of claim 1 , wherein a repair material is applied onto the repair surface by an additive manufacturing method.

14. The method of claim 1 , wherein a distance between the preserved part of the airfoil coating and the repair surface is not greater than 15% of a height of the blade body.

15. The method of claim 1 , wherein a distance between the preserved part of the airfoil coating and the repair surface is not greater than 12% of a height of the blade body.

16. The method of claim 1 , wherein a distance between the preserved part of the airfoil coating and the repair surface is not greater than 10% of a height of the blade body.

17. The method of claim 1 , wherein a distance between the preserved part of the airfoil coating and the repair surface is not greater than 7% of a height of the blade body.

18. The method of claim 1 , wherein a distance between the preserved part of the airfoil coating and the repair surface is not greater than 5% of a height of the blade body.

19. The method of claim 1 , wherein a distance between the preserved part of the airfoil coating and the repair surface is not greater than 4% of a height of the blade body.

20. The method of claim 1 , wherein a distance between the preserved part of the airfoil coating and the repair surface is not greater than 3% of a height of the blade body.

Assignees

• MTU Aero Engines AG

Inventors

• Seidel Frank
• Weidlich Nils

Classifications

• F05D2230/237

  Brazing · CPC title

• B23K31/10

  relating to cutting or desurfacing · CPC title

• F01D5/288

  Protective coatings for blades · CPC title

• F05D2220/32

  in gas turbines · CPC title

• F01D5/005 Primary

  Repairing methods or devices · CPC title