US4265681A
Expired / Lapsed
US
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Method of producing low loss pressed magnetic cores from microlaminations
Assignee: Westinghouse Electric Corp
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Filing: 1979-07-26
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Granted: 1981-05-05
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Expires: 1999-07-26
Abstract
Abstract A method for making pressed magnetic components having a low core loss characterized by the steps of compacting a plurality of substantially rectangular particles of an oriented iron alloy having a silicon content of from about 2.5% to about 3.5% and a carbon content of up to 0.01% into a compact of predetermined configuration, and stress-relief annealing the compact in a non-oxidizing atmosphere so as to provide a magnetizable compact having low core loss.
Inventors
- 👤 Robert F. Krause
- 👤 Norman M. Pavlik
- 👤 Kurt A. Grunert
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-01 23:39
CPC Classifications
H; H01; H01F; H01F1/00; H01F1/01; H01F1/03; H01F1/12; H01F1/14; H01F1/147; H01F1/14766; H01F1/14775; H01F1/14783
Claims Analysis
Total Claims: 14
Claim 1
Independent Claim
136 words
A method of making pressed magnetic core components having improved magnetic characteristics (a low core loss property) for use in electrical apparatus, comprising the steps of (a) providing silicon-iron alloy sheet stock having a thin coating of silicate glass on two opposite sides thereof and having a silicon content of from about 2.5% to 3.5%, a carbon content of up to 0.01%, manganese of from about 0.01% to 0.2%, and sulfur in the amount of from 0.005% to 0.25%, (b) forming microlaminations from the silicon-iron alloy sheet stock, which microlaminations comprise a coating of silicate glass on two opposite sides thereof, (c) coating the microlaminations with a dielectric material, (d) assembling the microlaminates within a mold of predetermined configuration, (e) compacting the microlaminates into a magnetizable compact, and (f) annealing the compacted microlaminates to relieve stresses.
Claim 2
Independent Claim
136 words
A method of making pressed magnetic core components having improved magnetic characteristics (a low core loss property) for use in electrical apparatus, comprising the steps of (a) providing silicon-iron alloy sheet stock having a thin coating of silicate glass on two opposite sides thereof and having a silicon content of from about 2.5% to 3.5%, a carbon content of up to 0.01%, manganese of from about 0.01% to 0.2%, and sulfur in the amount of from 0.005% to 0.25%, (b) forming microlaminations from the silicon-iron alloy sheet stock, which microlaminations comprise a coating of silicate glass on two opposite sides thereof, (c) coating the microlaminations with a dielectric material, (d) assembling the microlaminates within a mold of predetermined configuration, (e) compacting the microlaminates into a magnetizable compact, and (f) annealing the compacted microlaminates to relieve stresses.
Claim 3
Dependent Claim
15 words
The method of claim 1 in which the silicon content is from 2.75% to 3.3%.
Claim 4
Dependent Claim
13 words
The method of claim 2 in which the silicon content is about 3.2%.
Claim 5
Dependent Claim
15 words
The method of claim 1 in which the alloy stock is an oriented silicon steel.
Claim 6
Dependent Claim
13 words
The method of claim 1 in which the dielectric material is magnesium methylate.
Claim 7
Dependent Claim
25 words
The method of claim 1 in which the microlaminations are annealed at step (f) at a temperature between about 900° C. and about 950° C.
Claim 8
Dependent Claim
21 words
The method of claim 6 in which the temperature is between about 910° C. and about 940° C. at step (f).
Claim 9
Dependent Claim
14 words
The method of claim 7 in which the anneal temperature is about 925° C.
Claim 10
Dependent Claim
14 words
The method of claim 8 in which the anneal time is about 4 hours.
Claim 11
Independent Claim
134 words
A method of producing pressed magnetic core components having improved magnetic characteristics (a low core loss property) for use in electrical apparatus, comprising the steps of (a) providing silicon-iron alloy sheet stock having a thin coating of silicate glass on two opposite sides thereof, (b) forming particles of predetermined size and shape from said silicon iron alloy having a silicon content of from about 2.5% to about 3.5%, a carbon content of up to 0.01%, manganese of from about 0.01% to 0.2%, and sulfur in the amount of from 0.005% to 0.25%, (c) annealing the particles in a deoxidizing atmosphere, (d) coating the microlaminations with a dielectric material, (e) assembling the particles within a container of predetermined configurations, (f) compacting the particles into a magnetizable compact, and (g) annealing the compact to relieve stresses.
Claim 12
Independent Claim
134 words
A method of producing pressed magnetic core components having improved magnetic characteristics (a low core loss property) for use in electrical apparatus, comprising the steps of (a) providing silicon-iron alloy sheet stock having a thin coating of silicate glass on two opposite sides thereof, (b) forming particles of predetermined size and shape from said silicon iron alloy having a silicon content of from about 2.5% to about 3.5%, a carbon content of up to 0.01%, manganese of from about 0.01% to 0.2%, and sulfur in the amount of from 0.005% to 0.25%, (c) annealing the particles in a deoxidizing atmosphere, (d) coating the microlaminations with a dielectric material, (e) assembling the particles within a container of predetermined configurations, (f) compacting the particles into a magnetizable compact, and (g) annealing the compact to relieve stresses.
Claim 13
Dependent Claim
12 words
The method of claim 10 in which dielectric material comprising magnesium methylate.
Claim 14
Dependent Claim
20 words
The method of claim 11 in which the annealing step (f) occurs for about 4 hours at about 925° C.
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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) | 1984-05-04 | 1984-11-03 | 1985-05-05 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1988-05-04 | 1988-11-03 | 1989-05-05 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1992-05-04 | 1992-11-03 | 1993-05-05 | $7700.00 | Window Closed / Lapsed |