Steam turbine blade, and steam turbine and steam turbine power plant using the same
First Claim
Patent Images
1. A steam turbine blade made of a martensite steel having a 20°
- C. V-notch impact value, wherein said 20°
C. V-notch impact value is larger than a value (y) (kg·
m/cm2) calculated by an equation (y=−
0.44x+68) where (x) is a 20°
C. tensile strength (kg/mm2).
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Abstract
A steam turbine blade made of a martensite steel having high strength and high toughness, and a low pressure steam turbine and a steam turbine power generating plant using the steam turbine blades. The steam turbine blade is made of a martensite steel containing C of 0.13-0.40%; Si less than 0.5%; Mn less than 1.5%; Ni of 2-3.5%; Cr of 8-13%; Mo of 1.5-4%; at least one kind of Nb and Ta of 0.02-0.3% in total; V of 0.05-0.35; and N of 0.04-0.15%.
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Citations
19 Claims
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1. A steam turbine blade made of a martensite steel having a 20°
- C. V-notch impact value, wherein said 20°
C. V-notch impact value is larger than a value (y) (kg·
m/cm2) calculated by an equation (y=−
0.44x+68) where (x) is a 20°
C. tensile strength (kg/mm2). - View Dependent Claims (2, 3, 4, 5, 6, 7, 8)
- C. V-notch impact value, wherein said 20°
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9. A low pressure steam turbine comprising a rotor shaft;
- rotor blades mounted on said rotor shaft;
fixed blades for guiding flow of steam to said rotor blades; and
a casing holding said fixed blades, a rotating speed of the low pressure turbine being 3000 rpm or 3600 rpm, which comprises five stages of said rotor blades symmetrically arranged in both sides, and is of a double flow construction having said rotor blades in the first stages being mounted in a middle portions of said rotor shaft, andsaid rotor blades in the final stages are the steam turbine blades according to clam 1.
- rotor blades mounted on said rotor shaft;
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10. A low pressure steam turbine blade, which is made of a martensite steel containing C of 0.19-0.40%;
- Si less than 0.5%;
Mn less than 1.5%;
Ni of 2-3.5%;
Cr of 8-13%;
Mo of 1.5-4%;
at least one kind of Nb and Ta of 0.02-0.3% in total;
V of 0.05-0.35; and
N of 0.04-0.15%, on the basis of weight. - View Dependent Claims (11, 12, 13, 14, 15, 16, 17)
- Si less than 0.5%;
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18. A steam turbine blade having a blade length above 45 inches for a 3000 rpm turbine or a blade length above 37.5 inches for a 3600 rpm turbine, which is made of a martensite steel containing C of 0.19-0.40%;
- Si less than 0.5%;
Mn less than 1.5%;
Ni of 2-3.5%;
Cr of 8-13%;
at least one kind of Nb and Ta of 0.02-0.3% in total;
V of 0.05-0.35%; and
N of 0.04-0.15%, on the basis of weight and a 20°
C. tensile strength larger than 140 kg/mm2.
- Si less than 0.5%;
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19. A steam turbine blade having a blade length above 45 inches for a 3000 rpm turbine or a blade length above 37.5 inches for a 3600 rpm turbine, which is made of a martensite steel containing C of 0.19-0.40%;
- Si less than 0.5%;
Mn less than 1.5%;
Ni of 2-3.5%;
Cr of 8-13%;
at least one kind of Nb and Ta of 0.02-0.3% in total;
V of 0.05-0.35%; and
N of 0.04-0.15%, on the basis of weight, whereina combination of said amount of C and said amount of Mo falls within a range formed by connecting to points A (0.21%, 1.5%), B(0.15%, 2.5%), C(0.15%, 3.2%) and D(0.25%, 4.0%) and a 20°
C. tensile strength larger than 140 kg/mm2.
- Si less than 0.5%;
Specification