When a hot end blade for a gas turbine is designed, several failure criteria must be considered to insure reliability. The criteria include (but are not limited to) creep rupture, low-cycle fatigue, high-cycle fatigue, and creep deflection. This paper will focus on the second-stage turbine blade for the GE MS6001 industrial gas turbine. BP Amoco has experienced failure of this blade due to excessive creep deflection. Creep deflection rate is a function of stress level and metal temperature. A typical approach to reducing creep deflection is to reduce the bulk temperature in the blade. In this paper a design is reviewed that has had the stress redistributed, so that the high-temperature regions of the airfoil are at a lower stress level, thereby reducing the creep rate to an acceptable level.

Issue Section:
Technical Papers
Keywords:
gas turbines, stress analysis, stress control, creep fracture, fatigue, stress effects, high-temperature effects, design engineering
Topics:
Blades, Creep, Stress, Temperature, Deflection, Design, Airfoils, Gas turbines
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Granacher, J., and Preussler, T., 1987, “Creep of Some Gas Turbine Materials,” Advances in Materials Technology for Fossil Powered Plants, pp. 511–518.
Copyright © 2004
 by ASME
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