US5201791A
Expired / Lapsed
US
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Single alloy system for turbine components exposed substantially simultaneously to both high and low temperature
Assignee: Siemens Energy Inc
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Filing: 1991-06-27
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Granted: 1993-04-13
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Expires: 2011-06-27
Abstract
Abstract This invention provides alloys having optimum high and low temperature mechanical properties for use of both the high and low pressure ends of turbine rotors in a single row power generation turbine with a service temperature profile from about 75°-1200° F. (24°-649° C.). The alloys include about 8.00-9.5 wt. % Cr and about 0.85-1.05 wt. % Mo and are heat treated at 1225°-1350° F. (663°-732° C.) for at least about one hour. The alloys and the components manufactured from these alloys preferably include a room temperature 0.2% yield strength of about 80-110 ksi (551-758 MPa).
Inventors
- 👤 Robert E. Clark
- 👤 Dennis R. Amos
- 👤 Robert L. Novak
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-01 19:44
CPC Classifications
F; F01; F01D; F01D5/00; F01D5/12; F01D5/28; C; C22; C22C; C22C38/00; C22C38/18; C22C38/22
Claims Analysis
Total Claims: 12
Claim 1
Independent Claim
150 words
A method of operating an electric power plant having a single alloy system turbine rotor exposed to a high temperature and high pressure steam source and a low temperature and a low pressure exit end, comprising: providing a single alloy system rotor consisting essentially of a 9Cr-1Mo, mod. alloy which has been normalized and then tempered at an elevated temperature of about 1275°-1300° F. (690°-704° C.) for one hour per inch of its thickness; and operating said rotor in an electric power plant at a power generation turbine service temperature profile of about 75° F. (24° C.) at the exit end up to about 1200° F. (649° C.) at the source, said profile encompassing a high temperature and low temperature profile whereby said high temperature profile is from about 800° F.-1200° F. (427°-649° C.) and said low temperature profile is from about 75° F. to about 800° F. (24°-427° C.).
Claim 2
Independent Claim
150 words
A method of operating an electric power plant having a single alloy system turbine rotor exposed to a high temperature and high pressure steam source and a low temperature and a low pressure exit end, comprising: providing a single alloy system rotor consisting essentially of a 9Cr-1Mo, mod. alloy which has been normalized and then tempered at an elevated temperature of about 1275°-1300° F. (690°-704° C.) for one hour per inch of its thickness; and operating said rotor in an electric power plant at a power generation turbine service temperature profile of about 75° F. (24° C.) at the exit end up to about 1200° F. (649° C.) at the source, said profile encompassing a high temperature and low temperature profile whereby said high temperature profile is from about 800° F.-1200° F. (427°-649° C.) and said low temperature profile is from about 75° F. to about 800° F. (24°-427° C.).
Claim 3
Independent Claim
140 words
A method of using a single alloy system turbine rotor, exposed to a high temperature and high pressure steam source and a low temperature and low pressure exit end, consisting essentially of an ASTM A182, F91, 9Cr-1Mo, mod. alloy, substantially all of said alloy heat treated from at least about one hour at a temperature of about 1225°-1350° F. (663°-732° C.) for obtaining a FATT 50 of less than about 80° F. (26.6° C.), comprising: exposing said single alloy system rotor to a power generation turbine service temperature profile of about 75° F. (24° C.) at the exit end up to about 1200° F. (649° C.) at the source said profile encompassing a high temperature and a low temperature profile, wherein the low temperature profile is from about 75°-800° F. and the high temperature profile is from about 800°-1200° F.
Claim 4
Independent Claim
140 words
A method of using a single alloy system turbine rotor, exposed to a high temperature and high pressure steam source and a low temperature and low pressure exit end, consisting essentially of an ASTM A182, F91, 9Cr-1Mo, mod. alloy, substantially all of said alloy heat treated from at least about one hour at a temperature of about 1225°-1350° F. (663°-732° C.) for obtaining a FATT 50 of less than about 80° F. (26.6° C.), comprising: exposing said single alloy system rotor to a power generation turbine service temperature profile of about 75° F. (24° C.) at the exit end up to about 1200° F. (649° C.) at the source said profile encompassing a high temperature and a low temperature profile, wherein the low temperature profile is from about 75°-800° F. and the high temperature profile is from about 800°-1200° F.
Claim 5
Dependent Claim
17 words
The method of claim 2 wherein said heat treatment comprises tempering said alloy for about 5-20 hours.
Claim 6
Dependent Claim
19 words
The method of claim 3 wherein said tempering comprises heating to a temperature of about 1275°-1300° F. (690°-704° C.).
Claim 7
Dependent Claim
18 words
The method of claim 2 wherein said rotor has been substantially normalized at about 1900°-2000° F. (1038°-1093° C.).
Claim 8
Dependent Claim
20 words
The method of claim 5 wherein said rotor has been normalized up to about 1 hour per inch of thickness.
Claim 9
Dependent Claim
23 words
The method of claim 5 wherein said rotor has been normalized at about 1900° F. (1038° C.) for at least about one hour.
Claim 10
Dependent Claim
21 words
The method of claim 2 wherein said rotor has a room temperature 0.2% yield strength of about 80-110 ksi (551-758 MPa).
Claim 11
Dependent Claim
16 words
The method of claim 2 wherein said rotor comprises a FATT 50 below about room temperature.
Claim 12
Dependent Claim
31 words
The method of claim 2 wherein said alloy has an elongation of about 18-40% and a reduction in area of about 71-83% for a room temperature tensile test at 0.2% offset.
References Cited (Backward Citations)
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