초록 ▼

A method of repairing a turbine blade having a radially extending outer wall defining an internal cavity width and a blade tip. The method comprises removing at least a portion of the blade tip to form a repair surface and providing a tip cap having a radially outer side with an outer width that may

A method of repairing a turbine blade having a radially extending outer wall defining an internal cavity width and a blade tip. The method comprises removing at least a portion of the blade tip to form a repair surface and providing a tip cap having a radially outer side with an outer width that may be less than the internal cavity width, and having a radially inner side with an inner width that is substantially equal to or greater than the internal cavity width. The tip cap is positioned at the repair surface, and the tip cap is welded to the repair surface using a ductile welding material. A cap peripheral portion is formed by build-up welding around the tip cap, and a squealer portion is formed by build-up welding on the cap peripheral portion.

대표청구항 ▼

1. A method of repairing a turbine blade having a radially extending outer wall defining an internal cavity width and a blade tip, the method comprising: removing at least a portion of the blade tip to form a repair surface;providing a tip cap having a radially outer side with an outer width less th

1. A method of repairing a turbine blade having a radially extending outer wall defining an internal cavity width and a blade tip, the method comprising: removing at least a portion of the blade tip to form a repair surface;providing a tip cap having a radially outer side with an outer width less than said internal cavity width and a radially inner side with an inner width substantially equal to or greater than said internal cavity width;positioning said tip cap at said repair surface such that said radially outer side does not overlap said outer wall, wherein a notch is formed between a periphery of said tip cap and said repair surface;performing a first welding operation welding said tip cap to said repair surface, said first welding operation including forming a weld bead using a first welding material filling in said notch around the periphery of said tip cap; andperforming a second welding operation including build-up welding to form a cap peripheral portion using a second welding material, different from said first welding material, formed over said first welding material and extending on said repair surface between said tip cap and an outer surface of said outer wall;wherein said first welding material forming said weld bead filling in said notch has a higher ductility than a ductility of said second welding material forming said cap peripheral portion, and wherein, following said second welding operation, said first welding material remains in said notch separating said second welding material from contact with said tip cap and said repair surface at said notch. 2. The method as set forth in claim 1, including forming a replacement squealer portion on said cap peripheral portion by welding, wherein said replacement squealer portion comprises a material different than said second welding material used for forming said cap peripheral portion. 3. The method as set forth in claim 1, wherein said providing a tip cap further comprises providing a radially outer side surface, a radially inner side surface, a pressure side surface, and a suction side surface, wherein said radially outer side surface and said radially inner side surface are substantially parallel and said pressure side surface and said suction side surface are substantially non-parallel extending in a radial direction. 4. The method as set forth in claim 1, wherein said providing a tip cap further comprises providing a radially outer side surface, a radially inner side surface, and a plurality of pressure side surfaces and suction side surfaces. 5. The method as set forth in claim 4, wherein one of said pressure side surfaces is located adjacent to said repair surface and one of said suction side surfaces is located adjacent to said repair surface, and said pressure and suction side surfaces located adjacent to said repair surface are substantially non-parallel relative to each other, extending in a radial direction. 6. The method as set forth in claim 4, wherein said tip cap has a top hat cross section including a radially inner perimeter portion in overlapping relation to said repair surface, and a radially outer perimeter portion in non-overlapping relation to said repair surface. 7. The method as set forth in claim 6, wherein: said filler material generally extends along said pressure and suction side surfaces a radial distance that is no greater than a radial extent of said radially inner perimeter portion. 8. The method as set forth in claim 1, wherein said weld bead formed by said first welding operation is formed as an outwardly curved bead extending from a location on a side wall of said tip cap radially spaced outwardly from said repair surface to said repair surface. 9. The method as set forth in claim 1, wherein said tip cap is configured with an airfoil shape and said outer width of said tip cap is less than said inner width of said tip cap, as measured perpendicular to a chordal line at locations along the chordal line. 10. A method of repairing a turbine blade having a radially extending outer wall defining an internal cavity width and a blade tip, the method comprising: removing at least a portion of the blade tip to form a repair surface;providing a tip cap having a radially inner side, and the tip cap including a periphery defined at the radially inner side and comprising overlapping sections and non-overlapping sections in a radial direction of the blade, the non-overlapping sections located over the internal cavity width;positioning said radially inner side of said tip cap on said repair surface such that said radially inner side of said tip cap overlaps said outer wall and engages said repair surface at said overlapping sections and said radially inner side of said tip cap does not overlap said outer wall at said non-overlapping sections;performing a first welding operation welding said tip cap to said repair surface at a notch formed by a junction between said tip cap and said repair surface; andperforming a second welding operation to form a cap peripheral portion extending between said tip cap and an outer surface of said outer wall. 11. The method as set forth in claim 10, wherein said overlapping and non-overlapping sections comprise alternating sections located around the periphery of said tip cap. 12. The method as set forth in claim 10, wherein said overlapping and non-overlapping sections define a serrated edge around the periphery of said tip cap. 13. The method as set forth in claim 10, wherein said welding said tip cap further comprises welding a joint between said tip cap and said repair surface with a material having a higher ductility than a ductility of said cap peripheral portion. 14. The method as set forth in claim 10, including forming a replacement squealer portion on said cap peripheral portion by welding, wherein said replacement squealer portion comprises a material different than a material used in said forming a cap peripheral portion by welding. 15. The method as set forth in claim 10, wherein: following said second welding operation, said first welding operation fills said notch with a first welding material; anda second welding material applied by said second welding operation is welded onto said repair surface between said first welding material and said outer surface of said outer wall. 16. A method of repairing a turbine blade defining an airfoil shape defining an internal cavity width and having a blade tip, the method comprising: removing at least a portion of the blade tip to form a repair surface;providing a tip cap having a radially inner side, and the tip cap including a periphery defined at the radially inner side and configured with a shape generally matching said airfoil shape, said periphery including protruding portions defining an undulating surface of said periphery at said radially inner side, the undulating surface defined by said protrusions extending in a direction generally perpendicular to a radial direction of said turbine blade;positioning said radially inner side of said tip cap on said repair surface such that at least a portion of said radially inner side of said tip cap, including said protrusions, overlaps said outer wall and engages said repair surface;performing a first welding operation welding said tip cap to said repair surface at a notch formed by a junction between said tip cap and said repair surface; andperforming a second welding operation to form a cap peripheral portion extending between said tip cap and an outer surface of said outer wall. 17. The method as set forth in claim 16, wherein said providing a tip cap further comprises providing a radially outer side surface, a radially inner side surface, a pressure side surface, and a suction side surface, wherein said radially outer side surface and said radially inner side surface are substantially parallel and said protruding portions extend from said radially outer side surface to said radially inner side surface. 18. The method as set forth in claim 16, wherein said undulating surface of said periphery comprise overlapping sections and non-overlapping sections in a radial direction of said blade, and said positioning said tip cap on said repair surface further comprises positioning said tip cap such that said periphery overlaps said outer wall at said overlapping sections and said tip cap does not overlap said outer wall at said non-overlapping sections. 19. The method as set forth in claim 16, wherein said welding said tip cap further comprises welding a joint between said tip cap and said repair surface with a material having a higher ductility than a ductility of said cap peripheral portion. 20. The method as set forth in claim 16, including forming a replacement squealer portion on said cap peripheral portion by welding, wherein said replacement squealer portion comprises a material different than a material used in said forming a cap peripheral portion by welding.