US4174983A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Fe-Cr-Co magnetic alloy processing
Assignee: AT&T Inc
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Filing: 1978-07-13
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Granted: 1979-11-20
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Expires: 1998-07-13
Abstract
Abstract A method is disclosed for making a metallic body having desirable magnetic properties. The metallic body is made from an alloy which contains Fe, Cr, and Co and which may also contain one or several additional ferrite forming elements such as, e.g., Zr, Mo, V, Nb, Ta, Ti, Al, Si, or W. According to the disclosed method the alloy is cooled at a rate of at least 60 degrees C. per hour from an initial temperature at which the alloy is in an essentially single phase alpha state to a second temperature which is in a vicinity of 600 degrees C. Subsequently, the alloy is cooled at a second, slower rate to a third temperature which is in the vicinity of 525 degrees C. The disclosed method allows for a relatively broad range of initial temperatures, is relatively insensitive to compositional variations of the alloy, and permits simple reclamation of suboptimally treated parts. As a consequence, the method is particularly suited for large scale industrial production of permanent magnets as may be used, e.g., in relays, ringers, and electro-acoustic transducers.
Inventors
- 👤 Gilbert Y. Chin
- 👤 Sungho Jin
- 👤 John T. Plewes
- 👤 Bud C. Wonsiewicz
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-27 23:29
CPC Classifications
C; C21; C21D; C21D6/00; C21D6/002; H; H01; H01F; H01F1/00; H01F1/01; H01F1/03; H01F1/032; H01F1/04
Claims Analysis
Total Claims: 19
Claim 1
Independent Claim
191 words
Method for producing a magnetic metallic body by an aging treatment of an alloy of which an aggregate amount of at least 95 weight percent consists of Fe, Cr, and Co, said aggregate amount having a Cr content in the range of 20-35 weight percent and a Co content in the range of 5-25 weight percent CHARACTERIZED IN THAT said aging treatment comprises the steps of (1) maintaining said alloy at a first temperature corresponding to an essentially single phase alpha state so as to produce in said alloy an essentially single phase alpha structure, (2) lowering the temperature of said alloy from said first temperature to a second temperature in the range of 585°-625° C. at a rate which over essentially the entire range of temperatures between said first temperature and said second temperature is in the range of 60°-650° C./h, and (3) lowering the temperature of said alloy from said second temperature to a third temperature in the range of 500°-550° C. at a rate which over essentially the entire range of temperatures between said second temperature and said third temperature is in the range of 2°-30° C./h. 20
Claim 2
Dependent Claim
191 words
Method for producing a magnetic metallic body by an aging treatment of an alloy of which an aggregate amount of at least 95 weight percent consists of Fe, Cr, and Co, said aggregate amount having a Cr content in the range of 20-35 weight percent and a Co content in the range of 5-25 weight percent CHARACTERIZED IN THAT said aging treatment comprises the steps of (1) maintaining said alloy at a first temperature corresponding to an essentially single phase alpha state so as to produce in said alloy an essentially single phase alpha structure, (2) lowering the temperature of said alloy from said first temperature to a second temperature in the range of 585°-625° C. at a rate which over essentially the entire range of temperatures between said first temperature and said second temperature is in the range of 60°-650° C./h, and (3) lowering the temperature of said alloy from said second temperature to a third temperature in the range of 500°-550° C. at a rate which over essentially the entire range of temperatures between said second temperature and said third temperature is in the range of 2°-30° C./h. 20
Claim 3
Dependent Claim
16 words
Method of claim 1 in which said first temperature is in the range of 650°-775° C.
Claim 4
Dependent Claim
15 words
Method of claim 1 in which said alloy consists essentially of Fe, Cr, and Co.
Claim 5
Dependent Claim
57 words
Method of claim 1 in which said alloy contains at least one fourth element selected from the group consisting of 0.1-1 weight percent Zr, 0.1-5 weight percent Mo, 0.1-5 weight percent V, 0.1-3 weight percent Nb, 0.1-3 weight percent Ta, 0.1-5 weight percent Ti, 0.1-3 weight percent Al, 0.1-3 weight percent Si, and 0.1-5 weight percent W.
Claim 6
Dependent Claim
22 words
Method of claim 1 in which said alloy is maintained at said first temperature for a period of at most 5 hours.
Claim 7
Dependent Claim
23 words
Method of claim 1 in which said alloy is maintained at said second temperature for a period of 10 minutes to 1 hour.
Claim 8
Dependent Claim
20 words
Method of claim 1 in which lowering of temperature in step (2) is carried out in an essentially linear fashion.
Claim 9
Dependent Claim
20 words
Method of claim 1 in which lowering of temperature in step (2) is carried out in an essentially exponential fashion.
Claim 10
Dependent Claim
56 words
Method of claim 1 in which said first rate is in the range of 60°-200° C. per hour when said Co content is 5 weight percent and in the range of 250°-650° C. per hour when said Co content is 25 weight percent, ranges corresponding to intermediate levels of Co content being obtained by linear interpolation.
Claim 11
Dependent Claim
25 words
Method of claim 1 in which lowering of temperature in step (3) is carried out according to an essentially linear or piecewise liner time-temperature relationship.
Claim 12
Dependent Claim
17 words
Method of claim 1 in which lowering of temperature in step (3) is carried out by steps.
Claim 13
Dependent Claim
20 words
Method of claim 1 in which lowering of temperature in step (3) is carried out in an essentially exponential fashion.
Claim 14
Dependent Claim
20 words
Method of claim 1 in which said alloy is maintained at said third temperature for a period of 1-5 hours.
Claim 15
Dependent Claim
13 words
Method of claim 1 in which said metallic body is shaped as cast.
Claim 16
Dependent Claim
18 words
Method of claim 1 in which said metallic body is shaped as hot work prior to step (1).
Claim 17
Dependent Claim
18 words
Method of claim 1 in which said metallic body is shaped as cold worked prior to step (1).
Claim 18
Dependent Claim
15 words
Method of claim 1 in which said metallic body is solution annealed prior to aging.
Claim 19
Dependent Claim
16 words
Method of claim 1 in which said metallic body is shaped as formed by powder metallurgy.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1982-11-19 | 1983-05-21 | 1983-11-20 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1986-11-19 | 1987-05-21 | 1987-11-20 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1990-11-19 | 1991-05-21 | 1991-11-20 | $7700.00 | Window Closed / Lapsed |