Development and evaluation of life assessment and reconditioning methods for gas turbine blading

Technical Report · Sat Jun 01 00:00:00 EDT 1991

OSTI ID:5425641

Buergel, R; Ebeling, W; Ellner, J; Fried, R; Hoffelner, W; Kasik, N; Nazmy, M; Schneider, K; Scholz, A; Sova, V; Staubli, M ^[1]

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1. ABB Asea Brown Boveri, Baden (Switzerland)

The blades and vanes of power generating gas turbines are critical components which can limit the turbine life. They normally subject to degradation as a result both of microstructural changes, resulting in embrittlement and creep life exhaustion and of environmental attack, leading to destruction of protective coatings (if present) and the base material itself. The aim of this program has firstly been review methods of life assessment and develop techniques for the evaluation of blade condition. These include both non destructive methods such as eddy-current testing to determine chromium depletion of the surface layers and destructive techniques such as blade sectioning and metallographic investigation. Secondly the work has been directed towards reconditioning of service-exposed blades. This part included the development of techniques for stripping used coatings, electropolishing the resulting surface to permit effective nondestructive examination of the base material and heat treatment of the base material to regenerate the mechanical properties. Either pressureless heat treatment or hot isostatic pressing can be employed depending on the condition of the blade. Material missing as a result of cracking or foreign object damage can be replaced by electrodeposition, plasma spraying, brazing or welding. These techniques have been investigated and their advantages and disadvantages demonstrated. 158 refs., 251 figs., 18 tabs.

• Research Organization: Electric Power Research Inst., Palo Alto, CA (United States); ABB Asea Brown Boveri, Baden (Switzerland)
• Sponsoring Organization: EPRI; Electric Power Research Inst., Palo Alto, CA (United States)
• OSTI ID: 5425641
• Report Number(s): EPRI-GS-7302
• Country of Publication: United States
• Language: English

Related Subjects

20 FOSSIL-FUELED POWER PLANTS
36 MATERIALS SCIENCE
TURBINE BLADES
MAINTENANCE
REPAIR
TESTING
BRAZING
CHROMIUM
CLEANING
CORROSION
CREEP
DESTRUCTIVE TESTING
EDDY CURRENT TESTING
ELECTROPOLISHING
FOSSIL-FUEL POWER PLANTS
HEAT TREATMENTS
INCONEL 738
NICKEL ALLOYS
NONDESTRUCTIVE TESTING
PROTECTIVE COATINGS
SERVICE LIFE
TENSILE PROPERTIES
ALLOYS
CHEMICAL REACTIONS
COATINGS
ELECTROLYSIS
ELECTROMAGNETIC TESTING
ELEMENTS
FABRICATION
INCONEL ALLOYS
JOINING
LYSIS
MATERIALS TESTING
MECHANICAL PROPERTIES
METALS
NICKEL BASE ALLOYS
POLISHING
POWER PLANTS
SURFACE FINISHING
THERMAL POWER PLANTS
TRANSITION ELEMENTS
WELDING
200104* - Fossil-Fueled Power Plants- Components
360103 - Metals & Alloys- Mechanical Properties