Verification of creep and fatigue damage assessment techniques for turbine rotors in fossil power plants

Conference · Sat Dec 31 04:00:00 EST 1994

OSTI ID:82746

Ogata, Takashi; Nitta, Akito ^[1]; Ohkoda, Tadao ^[2]

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1. Central Research Inst. of Electric Power Industry, Tokyo (Japan). Dept. of Material Science
2. Japan Power Engineering and Inspection Corp., Tokyo (Japan). Dept. of Welding Engineering

A 5-year national project regarding the damage assessment techniques sponsored by the Ministry of International Trade and Industries had been implemented since 1989. The purpose is technological survey and demonstration tests of remaining life assessment techniques and to address life assessment procedure, and important points of them in application to actual components. At first, fundamental creep and fatigue tests with standard size specimens of a rotor material have been performed in laboratory to make samples with specified amount of damage. Several kinds of nondestructive (NDE) techniques including hardness measurement, microstructure observation and ultrasonic were applied, and correlation curves indicating the relationship between NDE damage parameters and creep and fatigue damages were established. Prediction accuracy of the NDE techniques have been demonstrated by using large scale artificial damaged samples. Creep damage of large scale samples could be predicted within the factor of 2 on actual damage by NDE techniques. Then analytical, destructive (DE) and NDE techniques were applied to long-term used rotors to verify applicability of these techniques. In the DE method, iso-stress creep tests have been performed by using miniature specimens taken from the first stage of the high pressure rotor and coupling portion. Damage assessment results obtained from three kinds of technique were consistent. The applicable range and appropriate selection criteria of remaining life assessment techniques for turbine rotors were established based on the consideration of characteristics of each method. Key points in actual application were also addressed.

• OSTI ID: 82746
• Report Number(s): CONF-941007--; ISBN 0-7918-1382-7
• Country of Publication: United States
• Language: English

Related Subjects

20 FOSSIL-FUELED POWER PLANTS
CREEP
FATIGUE
NONDESTRUCTIVE TESTING
ROTORS
STEAM TURBINES