US3884728A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Thermo-mechanical treatment of zirconium alloys
Assignee: Framatome ANP Richland Inc
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Filing: 1973-02-26
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Granted: 1975-05-20
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Expires: 1993-02-26
Abstract
Abstract A zirconium alloy comprising at least 95 percent zirconium, which has been thoroughly annealed, is greatly increased in strength without substantial loss in ductility by subjecting it to tensile creep deformation in a temperature range in which creep will occur, yet which is below the temperature for significant recovery.
Inventors
- 👤 Ira S Levy
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-10 01:47
CPC Classifications
C; C22; C22F; C22F1/00; C22F1/16; C22F1/18; C22F1/186; Y; Y10; Y10S; Y10S376/00; Y10S376/90
Claims Analysis
Total Claims: 20
Claim 1
Independent Claim
118 words
A METHOD OF TREATING A METAL COMPRISING AT LEAST 95 PERCENT ZIRCONIUM AND ALSO COMPRISING AT LEAST ONE CONSTITUENT SELECTED FROM THE CLASS CONSISTING OF CHROMIUM, TIN, NIOBIUM, IRON, TANTALUM, NICKEL AND ALUMINUM, WHICH METAL IS IN A THOROUGHLY ANNEALED CONDITION, SAID METHOD COMPRISING SUBJECTING SAID METAL TO A TENSIL CREEP STRAIN OF 3 TO 10 PERCENT WHILE HOLDING IT IN A TEMPERATURE RANGE IN WHICH CREEP WILL OCCUR, YET WHICH IS BELOW THE TEMPERATURE FOR SIGNIFICANT RECOVERY, SAID TENSIL CREEP STRAIN BEING ATTAINED BY TENSILE LOADING SAID METAL AT A STRAIN RATE OF ABOUT 0.001 TO 0.01 INCH/INCH/MINUTE UNTIL SAID STRAIN IS ATTAINED, FOLLOWED BY HOLDING SAID METAL AT THE FINALL LOAD FOR AT LEAST 15 MINUTES.
Claim 2
Independent Claim
118 words
A METHOD OF TREATING A METAL COMPRISING AT LEAST 95 PERCENT ZIRCONIUM AND ALSO COMPRISING AT LEAST ONE CONSTITUENT SELECTED FROM THE CLASS CONSISTING OF CHROMIUM, TIN, NIOBIUM, IRON, TANTALUM, NICKEL AND ALUMINUM, WHICH METAL IS IN A THOROUGHLY ANNEALED CONDITION, SAID METHOD COMPRISING SUBJECTING SAID METAL TO A TENSIL CREEP STRAIN OF 3 TO 10 PERCENT WHILE HOLDING IT IN A TEMPERATURE RANGE IN WHICH CREEP WILL OCCUR, YET WHICH IS BELOW THE TEMPERATURE FOR SIGNIFICANT RECOVERY, SAID TENSIL CREEP STRAIN BEING ATTAINED BY TENSILE LOADING SAID METAL AT A STRAIN RATE OF ABOUT 0.001 TO 0.01 INCH/INCH/MINUTE UNTIL SAID STRAIN IS ATTAINED, FOLLOWED BY HOLDING SAID METAL AT THE FINALL LOAD FOR AT LEAST 15 MINUTES.
Claim 3
Dependent Claim
28 words
A method as defined in claim 1 wherein said metal comprises at least 97.5 percent zirconium and also comprises tin and said temperature range is 200* to 350*C.
Claim 4
Dependent Claim
12 words
A method as defined in claim 2 wherein said metal is zircaloy-2.
Claim 5
Dependent Claim
21 words
A method as defined in claim 1 wherein said tensile creep strain in applied in increments of 3 to 5 percent.
Claim 6
Dependent Claim
22 words
A method as defined in claim 4 wherein the metal is allowed to cool to substantially room temperature between successive incremental strains.
Claim 7
Dependent Claim
33 words
A method as defined in claim 1 wherein said treatment consists in applying a single tensile creep strain of 3 to 5 percent and then allowing the metal to cool to room temperature.
Claim 8
Dependent Claim
38 words
A method as defined in claim 3, wherein said method consists in applying a single tensile creep elongation of substantially 5 percent at a temperature of substantially 225*C and then allowing the metal to cool to room temperature.
Claim 9
Dependent Claim
31 words
A method as defined in claim 2, wherein said method consists in applying a tensile loading at a temperature of substantially 225*C. until a strain of substantially 5 percent is attained.
Claim 10
Independent Claim
170 words
A method of treating tubing formed of a metal comprising at least 95 percent zirconium and also comprising at least one constituent selected from the class consisting of chromium, tin, niobium, iron, tantalum, nickel and aluminum, said tubing being formed by a series of cold working steps followed by a final stress relief, said method comprising the steps of (a) heating said tubing at a first temperature in the upper part of the alpha range of zirconium until the metal is in a thoroughly annealed condition, and (b) subjecting said tubing while in said annealed condition to a tensile creep strain of 3 to 10 percent while holding it at a second temperature in a range in which creep will occur yet which is below the temperature for significant recovery, said tensile creep strain being attained by tensile loading said metal at a strain rate of about 0.001 to 0.01 inch/inch/minute until said strain is attained, followed by holding said metal at the final load for at least fifteen minutes.
Claim 11
Independent Claim
170 words
A method of treating tubing formed of a metal comprising at least 95 percent zirconium and also comprising at least one constituent selected from the class consisting of chromium, tin, niobium, iron, tantalum, nickel and aluminum, said tubing being formed by a series of cold working steps followed by a final stress relief, said method comprising the steps of (a) heating said tubing at a first temperature in the upper part of the alpha range of zirconium until the metal is in a thoroughly annealed condition, and (b) subjecting said tubing while in said annealed condition to a tensile creep strain of 3 to 10 percent while holding it at a second temperature in a range in which creep will occur yet which is below the temperature for significant recovery, said tensile creep strain being attained by tensile loading said metal at a strain rate of about 0.001 to 0.01 inch/inch/minute until said strain is attained, followed by holding said metal at the final load for at least fifteen minutes.
Claim 12
Dependent Claim
40 words
A method as defined in claim 9 wherein said metal comprises at least 97.5 percent zirconium and also comprises tin, said first temperature is in the range 650* to 850*C. and said second temperature in the range 200* to 350*C.
Claim 13
Dependent Claim
12 words
A method as defined in claim 10 wherein said metal is zircaloy-2.
Claim 14
Dependent Claim
16 words
A method as defined in claim 9 wherein said strain is a unidirectional tensile creep elongation.
Claim 15
Dependent Claim
21 words
A method as defined in claim 12 wherein said tensile creep strain is applied in increments of 3 to 5 percent.
Claim 16
Dependent Claim
21 words
A method as defined in claim 13 wherein the tubing is allowed to cool to room temperature between successive incremental strains.
Claim 17
Dependent Claim
24 words
A method as defined in claim 12 wherein the tensile creep strain consists of a single tensile creep elongation of 3 to 5 percent.
Claim 18
Dependent Claim
32 words
A method as defined in claim 11 wherein the tensile creep strain consists of a single tensile elongation of substantially 5 percent and is carried out at a temperature of substantially 225*C.
Claim 19
Dependent Claim
35 words
A method as defined in claim 11 wherein said tubing is zircaloy-2 tubing that has been formed by a series of cold-working steps with a final stress relief in the range of 418*C to 538*C.
Claim 20
Dependent Claim
35 words
A method as defined in claim 17 wherein the tensile creep strain is carried out by applying a tensile elongation at a temperature of substantially 225*C. until a strain of substantially 5 percent is attained.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1978-05-19 | 1978-11-18 | 1979-05-20 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1982-05-19 | 1982-11-18 | 1983-05-20 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1986-05-19 | 1986-11-18 | 1987-05-20 | $7700.00 | Window Closed / Lapsed |