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

Technical Report · Sat Jun 01 04:00:00 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
200104* -- Fossil-Fueled Power Plants-- Components
36 MATERIALS SCIENCE
360103 -- Metals & Alloys-- Mechanical Properties
ALLOYS
BRAZING
CHEMICAL REACTIONS
CHROMIUM
CLEANING
COATINGS
CORROSION
CREEP
DESTRUCTIVE TESTING
EDDY CURRENT TESTING
ELECTROLYSIS
ELECTROMAGNETIC TESTING
ELECTROPOLISHING
ELEMENTS
FABRICATION
FOSSIL-FUEL POWER PLANTS
HEAT TREATMENTS
INCONEL 738
INCONEL ALLOYS
JOINING
LYSIS
MAINTENANCE
MATERIALS TESTING
MECHANICAL PROPERTIES
METALS
NICKEL ALLOYS
NICKEL BASE ALLOYS
NONDESTRUCTIVE TESTING
POLISHING
POWER PLANTS
PROTECTIVE COATINGS
REPAIR
SERVICE LIFE
SURFACE FINISHING
TENSILE PROPERTIES
TESTING
THERMAL POWER PLANTS
TRANSITION ELEMENTS
TURBINE BLADES
WELDING