Volume 18, Issue 6 (November 1990)
Bore Inspection and Life Evaluation of Vintage Steam Turbine/Generator Rotors
This paper describes the approach and methodology used for bore inspection and life evaluation/extension of vintage steam turbine spindles and generator rotors for continued service. The non-destructive inspections, including visual, magnetic particle, and ultrasonic, together with flaw sizing procedures, are described. Life evaluation and extension approaches include conventional and finite element stress and thermal analyses, state-of-the-art material evaluation studies, and fatigue, creep, and fracture mechanics based techniques. Based on the experience of these ongoing studies on over 250 spindles and rotors (manufactured by Allis-Chalmers, General Electric, and Westinghouse), two essential recommendations are made. Firstly, it is best to evaluate each vintage spindle/rotor on a case-by-case basis instead of a historical and generic basis. Secondly, most of the vintage spindles/rotors can continue to be used safely and with a high degree of reliability with proper periodic inspections and evaluations and life extension measures as needed.