Patent US4853298A successfully refreshed from Google Patents.
US4853298A
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Thermally stable super invar and its named article
Assignee: CRS Holdings LLC
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Filing: 1987-12-10
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Granted: 1989-08-01
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Expires: 2007-12-10
Abstract
Abstract A thermally stable Super Invar has a substantially suppressed martensitic transformation inception point as well as an average coefficient of thermal expansion substantially lower than Invar. The composition in weight percent consists essentially of ______________________________________ w/o ______________________________________ C 0.02 Max. Mn 0.4-0.8 Si up to 0.25 Ni 32.0-33.2 Co 4.5-5.5 ______________________________________ and the balance iron except for incidental amounts of other elements including up to 0.015 w/o P, 0.015 w/o S, 0.25 w/o Cr, 0.20 w/o Mo, 0.20 w/o. Cu, as well as other incidental elements in amounts which do not undesirably affect the austenitic microstructure or otherwise detract from the desired properties of the alloy. The composition is particularly suited for the manufacture of precision optical articles as well as other articles where minimal expansion mismatch between a metal member and a nonmetal member is required at temperatures of -90° C. (-130° F.) and lower. Moreover, the composition does not sustain stress induced martensite transformation for cold reductions up to 75%.
Inventors
- 👤 Leslie L. Harner
- 👤 Earl L. Frantz
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-02 21:35
CPC Classifications
C; C22; C22C; C22C38/00; C22C38/10; C22C38/105; Y; Y10; Y10T; Y10T428/00; Y10T428/12; Y10T428/12493; Y10T428/12535; Y10T428/12542; Y10T428/12549; Y10T428/12597
Claims Analysis
Total Claims: 26
Claim 1
Independent Claim
86 words
A low thermal expansion austenitic alloy which exhibits a martensitic transformation start temperature below -90 C. (-130 F.), an average coefficient of thermal expansion up to about 0.7×10 -6 /°C. from -55 C. to +90 C. (-67 F. to +194 F.), and which does not sustain stress-induced martensite transformation for cold reductions up to 75%, said alloy, in weight percent, consisting essentially of about ______________________________________
w/o
______________________________________
Carbon 0.02 Max.
Manganese 0.4-0.8
Silicon Up to 0.25
Nickel 32.0-33.2
Cobalt 2.5-5.5
______________________________________ and the balance essentially iron.
Claim 2
Dependent Claim
86 words
A low thermal expansion austenitic alloy which exhibits a martensitic transformation start temperature below -90 C. (-130 F.), an average coefficient of thermal expansion up to about 0.7×10 -6 /°C. from -55 C. to +90 C. (-67 F. to +194 F.), and which does not sustain stress-induced martensite transformation for cold reductions up to 75%, said alloy, in weight percent, consisting essentially of about ______________________________________
w/o
______________________________________
Carbon 0.02 Max.
Manganese 0.4-0.8
Silicon Up to 0.25
Nickel 32.0-33.2
Cobalt 2.5-5.5
______________________________________ and the balance essentially iron.
Claim 3
Dependent Claim
26 words
An alloy as recited in claim 1 having a martensitic transformation start temperature below -120 C. (-184 F.) which contains at least about 0.5 w/o manganese.
Claim 4
Dependent Claim
13 words
An alloy as recited in claim 1 containing up to 0.01 w/o carbon.
Claim 5
Dependent Claim
13 words
An alloy as recited in claim 3 containing up to 0.005 w/o carbon.
Claim 6
Dependent Claim
15 words
An alloy as recited in claim 1 containing no more than about 5.3 w/o cobalt.
Claim 7
Dependent Claim
14 words
An alloy as recited in claim 5 containing at least about 3.5 w/o cobalt.
Claim 8
Dependent Claim
15 words
An alloy as recited in claim 1 containing no more than about 32.8 w/o nickel.
Claim 9
Dependent Claim
13 words
An alloy as recited in claim 7 containing at least 32.2 w/o nickel.
Claim 10
Dependent Claim
19 words
An alloy as recited in claim 1 wherein the combined content of nickel and cobalt is about 35-38 w/o.
Claim 11
Dependent Claim
19 words
An alloy as recited in claim 9 wherein the combined content of nickel and cobalt is about 36-37.5 w/o.
Claim 12
Dependent Claim
98 words
A precision article comprising: a low expansion glass member; and a dimensionally stabilized metal member adjoining said glass member in close relation, said dimensionally stabilized metal member formed from an austenitic alloy having both a martensitic transformation start temperature below -90 C. (-130 F.) an average coefficient of thermal expansion no greater than 0.7×10 -6 /°C. from -55 C. to +90 C. (-67 F. to +194 F.), said alloy, in weight percent, consisting essentially of about ______________________________________
w/o
______________________________________
Carbon 0.02 Max.
Manganese 0.4-0.8
Silicon Up to 0.25
Nickel 32.0-33.2
Cobalt 2.5-5.5
______________________________________ and the balance essentially iron.
Claim 13
Dependent Claim
98 words
A precision article comprising: a low expansion glass member; and a dimensionally stabilized metal member adjoining said glass member in close relation, said dimensionally stabilized metal member formed from an austenitic alloy having both a martensitic transformation start temperature below -90 C. (-130 F.) an average coefficient of thermal expansion no greater than 0.7×10 -6 /°C. from -55 C. to +90 C. (-67 F. to +194 F.), said alloy, in weight percent, consisting essentially of about ______________________________________
w/o
______________________________________
Carbon 0.02 Max.
Manganese 0.4-0.8
Silicon Up to 0.25
Nickel 32.0-33.2
Cobalt 2.5-5.5
______________________________________ and the balance essentially iron.
Claim 14
Dependent Claim
32 words
An article as recited in claim 11 wherein said dimensionally stabilized metal member has a martensitic transformation start temperature below -120 C. (-184 F.) and contains at least about 0.6 w/o manganese.
Claim 15
Dependent Claim
18 words
An article as recited in claim 12 wherein said metal member contains up to about 0.01 w/o carbon.
Claim 16
Dependent Claim
17 words
An article as recited in claim 13 wherein said metal member contains up to 0.005 w/o carbon.
Claim 17
Dependent Claim
19 words
An article as recited in claim 11 wherein said metal member contains no more than about 5.3 w/o cobalt.
Claim 18
Dependent Claim
18 words
An article as recited in claim 15 wherein said metal member contains at least about 3.5 w/o cobalt.
Claim 19
Dependent Claim
19 words
An article as recited in claim 11 wherein said metal member contains no more than about 32.8 w/o nickel.
Claim 20
Dependent Claim
17 words
An article as recited in claim 17 wherein said metal member contains at least 32.2 w/o nickel.
Claim 21
Dependent Claim
23 words
An article as recited in claim 11 wherein said metal member has a combined content of nickel and cobalt of about 35-38 w/o.
Claim 22
Dependent Claim
23 words
An article as recited in claim 19 wherein said metal member has a combined content of nickel and cobalt of about 36-37.5 w/o.
Claim 23
Dependent Claim
37 words
An article as recited in claim 11 wherein the metal member is dimensionally stabilized by heat treating said metal member to accelerate the dimensional variation in the metal member due to precipitation of carbon within the alloy.
Claim 24
Dependent Claim
84 words
An article as recited in claim 21 wherein the metal member is heat treated by annealing the metal member in the temperature range 1200-1900 F., quenching the annealed metal member in water, stress relieving the metal member in the temperature range 500-800 F., cooling the stress relieved member in air, and then heating the metal member in the temperature range 200-400 F. for a time sufficient for the dimensional variation due to carbon precipitation in the alloy to reach a substantially steady state condition.
Claim 25
Dependent Claim
87 words
A low thermal expansion austenitic alloy which exhibits a martensitic transformation start temperature below -120 C. (-184 F.), an average coefficient of thermal expansion up to about 0.5×10 -6 /°C. from -55 C. to +90 C. (-67 F. to +194 F.), and which does not sustain stress-induced martensite transformation for cold reductions up to 75%, said alloy, in weight percent, consisting essentially of about ______________________________________
w/o
______________________________________
Carbon Up to 0.01
Manganese 0.5-0.6
Silicon Up to 0.25
Nickel 32.2-32.8
Cobalt 3.5-5.3
______________________________________ and the balance essentially iron.
Claim 26
Dependent Claim
87 words
A low thermal expansion austenitic alloy which exhibits a martensitic transformation start temperature below -120 C. (-184 F.), an average coefficient of thermal expansion up to about 0.5×10 -6 /°C. from -55 C. to +90 C. (-67 F. to +194 F.), and which does not sustain stress-induced martensite transformation for cold reductions up to 75%, said alloy, in weight percent, consisting essentially of about ______________________________________
w/o
______________________________________
Carbon Up to 0.01
Manganese 0.5-0.6
Silicon Up to 0.25
Nickel 32.2-32.8
Cobalt 3.5-5.3
______________________________________ and the balance essentially iron.
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) | 1992-07-31 | 1993-01-30 | 1993-08-01 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1996-07-31 | 1997-01-30 | 1997-08-01 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2000-07-31 | 2001-01-30 | 2001-08-01 | $7700.00 | Window Closed / Lapsed |