Patent US3868280A successfully refreshed from Google Patents.
US3868280A
Expired / Lapsed
US
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Method of forming electric insulating films oriented silicon steel
Assignee: Individual
•
Filing: 1973-08-16
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Granted: 1975-02-25
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Expires: 1993-08-16
Abstract
Abstract A method for producing a glassy film having an excellent insulating property on an oriented cold-rolled steel sheet by coating the surface of said silicon steel sheet with a mixture of a Ti compound and an Mg compound and possibly with the addition of a Mn compound thereto and then subjecting the coated silicon steel sheet to a heat-treatment.
Inventors
- 👤 Takaaki Yamamoto
- 👤 Kaneo Akanuma
- 👤 Osamu Tanaka
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-06 12:28
CPC Classifications
C; C23; C23C; C23C24/00; C23C24/08; C23C24/082; C23C24/085; C21; C21D; C21D8/00; C21D8/12; C21D8/1277; C21D8/1283; C23C8/00; C23C8/80; H; H01; H01F; H01F1/00; H01F1/01; H01F1/03; H01F1/12; H01F1/14; H01F1/147; H01F1/14766; H01F1/14775; H01F1/14783; C21D8/1244; C21D8/1255; C21D8/1272
Claims Analysis
Total Claims: 7
Claim 1
Independent Claim
161 words
A METHOD FOR PRODUCING AN ELECTRICAL INSULATION FILM ON AN ORIENTED COLD-ROLLED SILICON STEEL SHEET CONTAINING 0.01 TO 0.09 WT PERCENT SOL. AL, CONSISTING ESSENTIALLY OF THE STEPS OF FIRST SUBJECTING THE SILICON STEEL SHEET TO A HEAT-TREATMENT AT A TEMPERATURE OF 700* TO 900*C IN A REDUCING ATMOSPHERE OF EITHER HYDROGEN OR AN ATMOSPHERE CONTAINING DISSOCIATED AMMONIA HAVING A DEW POINT OF 55* TO 70*C FOR AT LEAST ONE MINUTE; APPLYING TO THE SURFACE OF THE STEEL SHET AN AQUEOUS SLURRY OF A MIXTURE OF (1) 2 TO 40 PARTS BY WEIGHT OF AT LEAST ONE COMPOUND SELECTED FROM THE GROUP CONSISTING OF AN OXIDE OF TI AND A HYDROXIDE OF TI, AND (2) 100 PARTS OF BY WEIGHT OF A COMPOUND SELECTED FROM THE GROUPS CONSISTING OF AN OXIDE OF MG AND A HYDROXIDE OF MG; DRYING THE STEEL SHEET COATED WITH THE SLURRY, AND ANNEALING THE SAID STEEL SHEET IN A HYDROGENCONTAINING ATMOSPHERE AT A TEMPERATURE ABOVE, 1,100*C.
Claim 2
Independent Claim
161 words
A METHOD FOR PRODUCING AN ELECTRICAL INSULATION FILM ON AN ORIENTED COLD-ROLLED SILICON STEEL SHEET CONTAINING 0.01 TO 0.09 WT PERCENT SOL. AL, CONSISTING ESSENTIALLY OF THE STEPS OF FIRST SUBJECTING THE SILICON STEEL SHEET TO A HEAT-TREATMENT AT A TEMPERATURE OF 700* TO 900*C IN A REDUCING ATMOSPHERE OF EITHER HYDROGEN OR AN ATMOSPHERE CONTAINING DISSOCIATED AMMONIA HAVING A DEW POINT OF 55* TO 70*C FOR AT LEAST ONE MINUTE; APPLYING TO THE SURFACE OF THE STEEL SHET AN AQUEOUS SLURRY OF A MIXTURE OF (1) 2 TO 40 PARTS BY WEIGHT OF AT LEAST ONE COMPOUND SELECTED FROM THE GROUP CONSISTING OF AN OXIDE OF TI AND A HYDROXIDE OF TI, AND (2) 100 PARTS OF BY WEIGHT OF A COMPOUND SELECTED FROM THE GROUPS CONSISTING OF AN OXIDE OF MG AND A HYDROXIDE OF MG; DRYING THE STEEL SHEET COATED WITH THE SLURRY, AND ANNEALING THE SAID STEEL SHEET IN A HYDROGENCONTAINING ATMOSPHERE AT A TEMPERATURE ABOVE, 1,100*C.
Claim 3
Dependent Claim
20 words
The method claimed in claim 1 wherein the oriented cold-rolled silicon steel sheet contains 2 to 3.5 wt. % Si.
Claim 4
Dependent Claim
43 words
The method claimed in claim 1 wherein the heat-treatment for forming SiO2 on the surface of the steel sheet comprises holding said steel sheet at a temperature of 700* to 900*C for at least one minute in a reducing atmosphere of hydrogen only.
Claim 5
Dependent Claim
52 words
The method claimed in claim 1 wherein the heat-treatment for forming SiO2 on the surface of the steel sheet comprises holding said steel sheet at a temperature of 700* to 900*C for at least one minute in a reducing atmosphere containing dissociated ammonia and having a dew point of 55* to 70*C.
Claim 6
Dependent Claim
58 words
The method claimed in claim 1 wherein the aqueous slurry is prepared by mixing the mixture with water and is applied on the surface of the oriented silicon steel sheet on which SiO2 has been formed in an amount such that the amount of the deposited material left after it has been dried is 2 to 10 g/m2.
Claim 7
Dependent Claim
18 words
The method claimed in claim 1 wherein only one compound from each group is mixed in said slurry.
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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) | 1978-02-24 | 1978-08-26 | 1979-02-25 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1982-02-24 | 1982-08-26 | 1983-02-25 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1986-02-24 | 1986-08-26 | 1987-02-25 | $7700.00 | Window Closed / Lapsed |