| 摘要 |
Provided is a rotor for a low-pressure turbine wherein the mechanical strength characteristics can be maintained even if the temperature of steam introduced into the low-pressure turbine becomes high, and no quality problem is posed without an increase in the manufacturing costs or days. The rotor for a low-pressure turbine which is used in a steam turbine facility equipped with a high-pressure turbine, an intermediate-pressure turbine and a low-pressure turbine is constituted such that a member formed of 1CrMoV steel, 2.25CrMoV steel or 10CrMoV steel and arranged on the steam inlet side and a member formed of 3.5Ni steel and arranged on the steam outlet side are joined by welding. Alternatively, a member formed of 3.5Ni steel and arranged on the steam inlet side and a member formed of 3.5Ni steel and arranged on the steam outlet side are joined by welding, wherein the member arranged on the steam inlet side is formed of low-impurity 3.5Ni steel containing Si:0.1% or less by wt%, Mn: 0.1% or less by wt%, and inevitable impurities of P:0.02% or less, S: 0.02% or less, Sn: 0.02% or less, As: 0.02% or less, Sb:0.02% or less, Al:0.02% or less, and Cu:0.1% or less by wt%. |
