Defects and Fracture Strength of Large Rotor Forgings for Steam Turbines Available to Purchase

Engineering criterion for brittle fracture of turbine rotors has been established based on the fracture mechanics and test results of fracture toughness and crack growth rate. From two typical large rotor forgings which contain defects in the region of center bore, the reliable K_IC data and crack growth rate data were obtained by various types of test specimens. The strength evaluation method of the rotor in the presence of defects has been completed as a form of allowable flaw size diagrams considering the loading conditions in service life of steam turbines.