INFLUENCE OF CASTING DEFECTS ON THE LOW CYCLE FATIGUE PERFORMANCE OF MAR-M247-A PATH TOWARDS A PROBABILISTIC MODEL

Intermittent renewable energy sources are becoming increasingly important. This creates a demand for more flexible gas turbine operation conditions, to fill supply gaps and manage peak loads. As a result, the number of startup and shutdown cycles - the low cycle fatigue (LCF) loading of a gas turbine component - increases substantially. This work investigates the LCF performance of a common rotor blade material, to support the future transition towards more flexible power plant operation. One of the goals of this multi-year government funded project is the development of a probabilistic life model of cast material including defects such as porosity. The focus of this work is the investigation of the influence of casting defects on the LCF performance of cast MAR-M247. A comprehensive test program on defective and defect-free specimens at realistic engine conditions, i.e., temperature and stress was conducted. A first deterministic fatigue life model that accounts for material defects is proposed.