| 摘要 |
PROBLEM TO BE SOLVED: To provide the excellent resistance to corrosion fatigue and prolong the service life of a steam turbine rotor by forming an electroless nickel plated layer which contains a specific amount of phosphorus and has a specific thickness on a surface of a section on which high stress of the turbine rotor made of low alloy steel acts repeatedly. SOLUTION: An electroless nickel plated layer 10 which controls the content of phosphorus to a scope of 7.5 to 9.5weight% and has a thickness of 10 to 30μm is formed on a surface of a section on which high stress of a turbine rotor 1 made of low alloy steel in a steam turbine rotor acts repeatedly. This electroless nickel plating is applied to the section where high stress of the turbine rotor 1 acts repeatedly, but may be applied on the whole surface of the turbine rotor 1 depending on conditions. A plating solution bath like a circular ring is attached to outer periphery of the rotor 1 and plating solution prepared in such a manner that it has predetermined concentration is circulated by a pump to form the electroless nickel plated layer 10 on an inner face of a blade groove 2 which is a blade mounting groove of the turbine rotor 1.
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