The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Sep. 26, 2000
Filed:
Feb. 21, 1995
Masao Shiga, Hitachi, JP;
Ryo Hiraga, Hitachiota, JP;
Takeshi Onoda, Hitachi, JP;
Nobuo Shimizu, Hitachi, JP;
Norio Yamada, Hitachiota, JP;
Mitsuo Kuriyama, Ibaraki-ken, JP;
Kishio Hidaka, Hitachi, JP;
Shigeyoshi Nakamura, Katsuta, JP;
Yutaka Fukui, Hitachi, JP;
Toshio Fujita, Tokyo, JP;
Hitachi, Ltd., , JP;
Abstract
A steam turbine includes a rotor shaft, movable blades assembled on the rotor shaft, fixed blades for guiding inflow of steam to the moving blades, and an inner casing for holding the fixed blades. The rotor shaft and at least a first stage of the movable blades are made of high-strength martensitic steel comprising 0.05-0.20(%) of C, at most 0.15(%) of Si, 0.3-0.7(%) of Mn, 9.5-13(%) of Cr, 0.3-0.7(%) of Ni, 0.05-0.35(%) of V, 0.02-0.15(%) of Nb, 0.01-0.06(%) of N, 0.05-0.5(%) of Mo, 1.0-3.5(%) of W, 2-10(%) of Co and 0.0005-0.03(%) of B and at least 78(%) of Fe (the percentages being given in terms of weight). The inner casings is made of martensitic cast steel comprising 0.06-0.16(%) of C, at most 0.5(%) of Si, at most 1(%) of Mn, 0.2-1.0(%) of Ni, 8-12(%) of Cr, 0.05-0.35(%) of V, 0.01-0.15(%) of Nb, 0.01-0.1(%) of N, at most 1.5% of Mo, 1-4(%) of W and 0.0005-0.03(%) of B and at least 85(%) of Fe (the percentages being given in terms of weight). The rotor shaft has a length of at least 5 (m) and has a minimum diameter of at least 600 (mm) at a portion where the fixed blades are assembled. The first stage of said moving blades has a length of at least 35 (mm) at a blade portion thereof.