Low-pressure turbine rotor

Abstract

The object of the invention is to provide a low-pressure turbine rotor capable of maintaining mechanical strength characteristics, and without problems in terms of quality without increasing manufacturing costs and manufacturing days, even if high temperature steam is introduced into the low-pressure turbine. A low-pressure turbine rotor used in a steam turbine facility including a high-pressure turbine, an intermediate-pressure turbine, and a low-pressure turbine includes a member formed from 1CrMoV steel, 2.25CrMoV steel, or 10CrMoV steel arranged on a steam inlet side, and a member formed from 3.5Ni steel arranged on a steam outlet side, which are joined together by welding. Alternatively, the member arranged on the steam inlet side and the member arranged on the steam outlet side, both of which are formed from 3.5Ni steel, are joined together by welding, and the member arranged on the steam inlet side is made of low-impurity 3.5Ni steel containing, by weight %, Si: 0.1% or less, Mn: 0.1% or less, and inevitable impurities containing, by weight %, 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.

1 . A low-pressure turbine rotor used in a steam turbine facility including a high-pressure turbine, an intermediate-pressure turbine, and a low-pressure turbine,
 the turbine rotor comprising a member formed from 1CrMoV steel, 2.25CrMoV steel, or 10CrMoV steel arranged on a steam inlet side, and a member formed from 3.5Ni steel arranged on a steam outlet side, which are joined together by welding.   
   
   
       2 . A low-pressure turbine rotor used in a steam turbine facility including a high-pressure turbine, an intermediate-pressure turbine, and a low-pressure turbine,
 the turbine rotor comprising a member arranged on a steam inlet side and a member arranged on a steam outlet side, which are joined together by welding, both the members being formed from 3.5Ni steel, and the member arranged on the steam inlet side being formed from low-impurity 3.5Ni steel.   
   
   
       3 . The low-pressure turbine rotor according to  claim 2 ,
 wherein the low-impurity 3.5Ni steel arranged on the steam inlet side contains, by weight %, Si: 0.1% or less, Mn: 0.1% or less, and inevitable impurities, by weight %, containing 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.   
   
   
       4 . The low-pressure turbine rotor according to  claim 1 ,
 wherein the low-pressure turbine rotor is used in a steam turbine facility where the inlet steam temperature of the low-pressure turbine is 380° C. or higher,   a region where the temperature of the steam passing through the low-pressure turbine attains temperatures of 380° C. or higher includes the member arranged on the steam inlet side, and   a region where the temperature of the steam passing through the low-pressure turbine is less than 380° C. includes the member arranged on the steam outlet side.   
   
   
       5 . The low-pressure turbine rotor according to  claim 1 ,
 wherein the low-pressure turbine rotor is used in a steam turbine facility where the inlet steam temperature of at least one of the high-pressure turbine and the intermediate-pressure turbine is 630° C. or higher.   
   
   
       6 . The low-pressure turbine rotor according to  claim 2 ,
 wherein the low-pressure turbine rotor is used in a steam turbine facility where the inlet steam temperature of the low-pressure turbine is 380° C. or higher,   a region where the temperature of the steam passing through the low-pressure turbine attains temperatures of 380° C. or higher includes the member arranged on the steam inlet side, and   a region where the temperature of the steam passing through the low-pressure turbine is less than 380° C. includes the member arranged on the steam outlet side.   
   
   
       7 . The low-pressure turbine rotor according to  claim 2 ,
 wherein the low-pressure turbine rotor is used in a steam turbine facility where the inlet steam temperature of at least one of the high-pressure turbine and the intermediate-pressure turbine is 630° C. or higher.   
   
   
       8 . The low-pressure turbine rotor according to  claim 3 ,
 wherein the low-pressure turbine rotor is used in a steam turbine facility where the inlet steam temperature of at least one of the high-pressure turbine and the intermediate-pressure turbine is 630° C. or higher.