STEAM TURBINE, TURBINE MOVING BLADE, DISC FOR STEAM TURBINE, TREATMENT METHOD OF STEAM TURBINE

摘要

PPROBLEM TO BE SOLVED: To solve the problem that a fork shape structure which is one of structures combining a turbine moving blade with a disc requires the improvement of fatigue strength and SCC resistance, since a pin hole and a pin for combining a wing fork with a disc fork are in a corrosive environment and also in an environment affected by a large centrifugal force. PSOLUTION: Stress improvement processing is performed on the inner surface of the pin hole 6 provided to penetrate the wing fork 2 provided at the turbine moving blade and the disc fork 4 provided at the disc to form a compression residual stress region. The pin hole 6 is formed by reaming, and by the reaming, tensile stress remaining on the inner surface of the pin hole 6 is eliminated and compression residual stress 7 is generated. Thereby, the fatigue strength and the SCC resistance of the steam turbine can be improved. PCOPYRIGHT: (C)2010,JPO&INPIT