Mitsubishi Hitachi Power Systems, Ltd.

Masayoshi Ohhira

Kunio Asai

Hideyuki Nomura

Keiko Shishime

Yasuyoshi Harashima

Takeshi Kashiwagi

Takafumi Wakasa

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 turbine includes a rotor having a plurality of rotor forks rowed in an axial direction; a turbine blade having blade forks arranged in the axial direction of the rotor, the blade forks engaged with the rotor forks; a plurality of pin holes whose positions are different from each other in the radial direction of the rotor; and a plurality of fork pins inserted into the plurality of pin holes in the axial direction of the rotor. A clearance exists between an inner diameter of the pin hole of the blade fork and a diameter of the fork pin, the clearance varying depending on positions in the axial direction of the turbine.

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Hitachi, Japan

Masayoshi Ohhira