STEAM TURBINE WITH FORK-TYPE BLADE ATTACHMENTS

摘要

A steam turbine having a fork-type joint structure is provided that secures sufficient strength for endurance of stress corrosion cracking, low-cycle fatigue and high-cycle fatigue and extends an operating life while making it possible to endure long-term operation. The steam turbine includes a turbine rotor 2 having a plurality of rotor forks 4a-4h rowed in an axial direction; a turbine blade 1 having blade forks 3a-3g rowed in the axial direction of the turbine rotor 2, the blade forks 3a-3g engaged with the rotor forks 4a-4h; a plurality of pin holes 6a, 7a whose positions are different from each other in the radial direction of the turbine rotor; and a plurality of fork pins 5a inserted into the plurality of pin holes in the axial direction of the turbine rotor, the plurality of fork pins each for joining the rotor fork and the blade fork. A clearance is defined between an inner diameter of the pin hole 6a of the blade fork 3a-3g and a diameter of the fork pin 5a and the clearance varies depending on positions in the axial direction of the turbine rotor.