Effectiveness Verification of Creep-Fatigue Assessment Procedures for Fast-Starting Steam Turbines

The paper reviews the methodology adopted in a Swiss Research Collaboration to devise a component-feature representative testpiece geometry and the thermo-mechanical fatigue (TMF) cycle parameters necessary to closely simulate the most arduous conceivable operating duties in steam turbines exposed to cyclic operation. Implementation of these service-like experimental conditions provides a practical indication of the effectiveness of deformation and crack initiation endurance predictions, in particular during fast turbine start-up conditions. Comprehensive post test inspection also provides evidence to demonstrate the physical realism of the laboratory simulations in terms of the creep-fatigue damage generated during the benchmark tests. Mechanical response results and physical damage observations are presented and their practical implications evaluated.Copyright © 2012 by ASME and Alstom Technologies Ltd.