| US 7,459,035 B2 | ||
| Steam turbine rotor and steam turbine plant | ||
| Shinya Imano, Hitachi (Japan); Hiroyuki Doi, Tokai (Japan); Hirotsugu Kawanaka, Hitach (Japan); and Eiji Saitou, Hitachi (Japan) | ||
| Assigned to Hitachi, Ltd., Tokyo (Japan) | ||
| Filed on Jun. 10, 2004, as Appl. No. 10/864,418. | ||
| Claims priority of application No. 2003-168578 (JP), filed on Jun. 13, 2003. | ||
| Prior Publication US 2004/0253102 A1, Dec. 16, 2004 | ||
| Int. Cl. C22C 19/05 (2006.01); C22C 30/00 (2006.01) | ||
| U.S. Cl. 148—410 [148/419; 420/447; 420/584.1] | 4 Claims |
| 1. A rotor of a steam turbine of which main steam temperature is 675° C. or more, wherein the rotor weighs 8 ton or more and
is made from a forged material of NiFe-base alloy consisting of:
Cr of 14 to 18 weight %;
Fe of 15 to 45 weight %;
Al of 1.0 to 2.0 weight %;
Ti of 1.0 to 1.8 weight %;
C and N of which the sum is 0.05 or less weight %;
Nb within the range defined by the formula;
3.5−(Fe weight %)/20<(Nb weight)<4.5−(Fe weight %)/20; and
the balance essentially Ni;
wherein a γ′ phase is precipitated in the NiFe-base alloy, the γ′ phase being Ni3A1; and
wherein the NiFe-base alloy does not contain γ″ phase.
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