Metallurgical Characterization of a High-Pressure Rotor for Remaining Service Life Assessment After 26 Years of Service

Abstract

In-service material degradation of a high-pressure rotor steel has been investigated for remaining service life assessment. The samples for this study were taken from the cold and hot locations of a rotor that had operated for approximately 167,500 hours. The test results have indicated that the rotor steel is slightly softened and temper embrittled as a result of service exposure. Based on isostress creep rupture data of the rotor steel in the service-exposure. Based on isostress creep rupture data of the rotor steel in the service-exposed condition, it is concluded that crack initiation due to creep is not a concern in the near future. Considering the uncertainties associated with the extrapolation of short-time rupture data on remaining service life assessment, the rotor material should be re-evaluated for degradation of properties after the next 10 years of operation.