Welded steam turbine rotor made of chromium alloy steel

摘要

It is an objective of the invention to provide a steam turbine rotor that is capable of both reducing stress corrosion cracking (SCC) susceptibility and improving low cycle fatigue (LCF) life thereof. There is provided a steam turbine rotor, comprising a rotor disk (1) in a low pressure final stage (L-0), and another rotor disk (2) in a plurality of stages including a stage (L-1) positioned closer to a high pressure side than the low pressure final stage (L-0), the rotor disk in the low pressure final stage (L-0) and the rotor disk in a plurality of stages including the stage (L-1) being joined by welding, wherein a material of both the rotor disk in the low pressure final stage and the rotor disk in a plurality of stages including the stage (L-1) is a 12Cr steel and has a tensile strength of 900 to 1200 MPa.