Metallurgical Factors Affecting the Reliability of Fossil Steam Turbine Rotors

Abstract

The reliability of steam turbine rotors is of concern both from the point of view of avoiding premature failures prior to the end of the design life and from the point of view of extending the plant life beyond the end of the design life. With respect to rotors that are already in service, improved methods for assessing the remaining life of the rotors are needed. Although some progress has been made toward repairing of damaged rotors, many utilities still consider it risky and would rather replace these rotors than repair them. With respect to new rotors, methods for improving their reliability under cyclic operational conditions and other higher temperature conditions may be needed. All these concerns can be addressed adequately only with improvements in our understanding of the metallurgical behavior of the rotors. This paper is intended to review the various metallurgical factors that affect the reliability of rotors.