Turbine buckets with high hot hardness shroud-cutting deposits

Patent metadata

Field	Value
Publication number	US-9909428-B2
Application number	US-201314090871-A
Country	US
Kind code	B2
Filing date	Nov 26, 2013
Priority date	Nov 26, 2013
Publication date	Mar 6, 2018
Grant date	Mar 6, 2018

Abstract

Turbine buckets include a pressure side, a suction side opposite the pressure side, and a bucket squealer tip attached to the pressure side and the suction side. The bucket squealer tip includes a plurality of high hot hardness shroud-cutting deposits deposited on its exterior surface that have a hardness of at least about 1100 kg mm −2 and a melting temperature of at least about 1500° C.

First claim

What is claimed is:

1. A turbine bucket comprising:
a pressure side;
a suction side opposite the pressure side; and,
a bucket squealer tip attached to the pressure side and the suction side comprising a plurality of high hot hardness shroud-cutting deposits deposited on an exterior surface of the bucket squealer tip, wherein the plurality of high hot hardness shroud-cutting deposits have a hardness of at least about 1100 kg mm −2 and a melting temperature of at least about 1500° C., wherein the plurality of high hot hardness shroud-cutting deposits are selected from the group consisting of CrN, Cr 3 C 2 , HfN, HfC, WC, Al 2 O 3 , SiC, BN, B 4 C and diamond carbon, and, wherein at least a first high hot hardness shroud cutting deposit comprises a first composition and at least a second high hot hardness shroud cutting deposit comprises a second composition different than the first composition, wherein the high hot hardness shroud-cutting deposits comprise a plurality of hard particles mixed with one or more braze filler metals wherein the plurality of hard particles deposits comprise both cubic boron nitride (CBN) and alumina (Al 2 O 3 ) at a ratio from about 50:50 to about 20:80.

2. The turbine bucket of claim 1 , wherein the high hot hardness shroud-cutting deposits comprise a cobalt-chromium-molybdenum alloy.

3. The turbine bucket of claim 1 , wherein the plurality of high hot hardness shroud-cutting deposits have a hardness of at least about 2000 kg mm −2 and a melting temperature of at least about 2000° C.

4. The turbine bucket of claim 1 , wherein the exterior surface of the bucket squealer tip comprises a thermal barrier coating.

5. The turbine bucket of claim 4 , wherein the thermal barrier coating is a patterned thermal barrier coating.

6. The turbine bucket of claim 1 , wherein at least one of the high hot hardness shroud-cutting deposits comprises a tapered point distal the exterior surface.

7. The turbine bucket of claim 1 , wherein at least a first high hot hardness shroud cutting deposit comprises a first shape and at least a second high hot hardness shroud cutting deposit comprises a second shape different than the first shape.

8. A method for modifying a turbine bucket having a pressure side opposite a suction side and a bucket squealer tip attached to the pressure side and the suction side, the method comprising:
depositing a plurality of high hot hardness shroud-cutting deposits on an exterior surface of the bucket squealer tip, wherein the plurality of high hot hardness shroud-cutting deposits have a hardness of at least about 1100 kg mm −2 and a melting temperature of at least about 1500° C., wherein at least a first high hot hardness shroud cutting deposit comprises a first composition and at least a second high hot hardness shroud cutting deposit comprises a second composition different than the first composition, and, wherein the high hot hardness shroud-cutting deposits comprise a plurality of hard particles mixed with one or more braze filler metals, and wherein the plurality of hard particles are selected from the group consisting of CrN, Cr 3 C 2 , HfN, HfC, WC, Al 2 O 3 , SiC, BN, B 4 C and diamond carbon, wherein the plurality of hard particles deposits comprise both cubic boron nitride (CBN) and alumina (Al 2 O 3 ) at a ratio from about 50:50 to about 20:80.

9. The method of claim 8 , wherein the plurality of high hot hardness shroud-cutting deposits are deposited via pulsed laser welding.

10. The method of claim 8 further comprising coating the bucket squealer tip with a thermal barrier coating before depositing the plurality of high hot hardness shroud-cutting deposits on the exterior surface.

11. The method of claim 8 , wherein the plurality of high hot hardness shroud-cutting deposits have a hardness of at least about 2000 kg mm −2 and a melting temperature of at least about 2000° C.

12. The method of claim 8 , wherein at least a first high hot hardness shroud cutting deposit is deposited in a first shape and at least a second high hot hardness shroud cutting deposit is deposited in a second shape different than the first shape.

13. The method of claim 8 , wherein at least one of the high hot hardness shroud-cutting deposits comprises a tapered point distal the exterior surface.

14. The method of claim 8 , wherein the high hot hardness shroud-cutting deposits comprise a cobalt-chromium-molybdenum alloy.

15. A method for modifying a turbine bucket having a pressure side opposite a suction side and a bucket squealer tip attached to the pressure side and the suction side, the method comprising:
depositing a plurality of high hot hardness shroud-cutting deposits on an exterior surface of the bucket squealer tip, wherein the plurality of high hot hardness shroud-cutting deposits have a hardness of at least about 1100 kg mm −2 and a melting temperature of at least about 1500° C., wherein at least a first high hot hardness shroud cutting deposit comprises a first composition and at least a second high hot hardness shroud cutting deposit comprises a second composition different than the first composition, and, wherein the high hot hardness shroud-cutting deposits comprise a plurality of hard particles mixed with one or more braze filler metals, and wherein the plurality of hard particles are selected from the group consisting of CrN, Cr 3 C 2 , HfN, HfC, WC, Al 2 O 3 , SiC, BN, B 4 C and diamond carbon wherein the plurality of high hot hardness shroud-cutting deposits comprise both cubic born nitride (CBN) and alumina (Al 2 O 3 ) at a ratio from about 50:50 to about 20:80.

Assignees

• Gen Electric

Inventors

• Kottilingam Srikanth Chandrudu
• Pabla Surinder Singh
• Tollison Brian Lee

Classifications

• B22F10/28

  Powder bed fusion, e.g. selective laser melting [SLM] or electron beam melting [EBM] · CPC title

• F05D2300/175

  Superalloys · CPC title

• B23K2203/16

  Operations & Transport · mapped topic

• F01D5/288

  Protective coatings for blades · CPC title

• B23K2203/08

  Operations & Transport · mapped topic