Patent US3856568A successfully refreshed from Google Patents.
US3856568A
Expired / Lapsed
US
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Method for forming an insulating film on an oriented silicon steel sheet
Assignee: Nippon Steel Corp
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Filing: 1972-09-27
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Granted: 1974-12-24
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Expires: 1992-09-27
Abstract
Abstract A method for producing an oriented silicon steel sheet which a surface film, which improves iron loss and magnetostriction characteristics of the steel sheet, comprising the steps of applying to the surface of the oriented steel sheet a coating solution composed of 4 to 16 wt. percent of colloidal silica, 3 to 24 wt. percent of aluminum phosphate and 0.2 to 4.5 wt. percent of at least one compound selected from the group consisting of chromic anhydride and chromate with or without the addition of 1 to 5 grams of boric acid and baking the thus applied coating solution at a temperature above 350*C.
Inventors
- 👤 O Tanaka
- 👤 T Yamamoto
- 👤 T Takata
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-25 13:16
CPC Classifications
H; H01; H01F; H01F1/00; H01F1/01; H01F1/03; H01F1/12; H01F1/14; H01F1/147; H01F1/14766; H01F1/14775; H01F1/14783; C; C21; C21D; C21D1/00; C21D1/68; C21D1/70; C21D8/00; C21D8/12; C21D8/1277; C21D8/1288; C23; C23C; C23C22/00; C23C22/05; C23C22/06; C23C22/24; C23C22/33; C23C22/73; C23C22/74
Claims Analysis
Total Claims: 7
Claim 1
Independent Claim
70 words
A METHOD FOR FORMING AN INSULATING FILM ON AN ORIENTED SILICON STEEL SHEET COMPRISING THE STEPS OF APPLYING TO THE ORIENTED SILCON STEEL SHEET A COATING SOLUTION COMPOSED OF 4 TO 16 WT. PERCENT OF COLLOIDAL SILICA, 3 TO 24 WT. PERCENT OF ALUMINUM PHOSPHATE, CALCULATED AS ALUMINUM BIPHOSPHATE AND 0.2 TO 4.5 WT. PERCENT OF AT LEAST ONE COMPOUND SELECTED FROM THE GROUP CONSISTING OF CHROMIC ANHYDRIDE AND CHROMATE
Claim 2
Independent Claim
70 words
A METHOD FOR FORMING AN INSULATING FILM ON AN ORIENTED SILICON STEEL SHEET COMPRISING THE STEPS OF APPLYING TO THE ORIENTED SILCON STEEL SHEET A COATING SOLUTION COMPOSED OF 4 TO 16 WT. PERCENT OF COLLOIDAL SILICA, 3 TO 24 WT. PERCENT OF ALUMINUM PHOSPHATE, CALCULATED AS ALUMINUM BIPHOSPHATE AND 0.2 TO 4.5 WT. PERCENT OF AT LEAST ONE COMPOUND SELECTED FROM THE GROUP CONSISTING OF CHROMIC ANHYDRIDE AND CHROMATE
Claim 3
Dependent Claim
34 words
The method according to claim 1, in which boric acid is added to the coating solution in an amount of 1 to 5 grams per 100 cc. of a water dispersion of colloidal silica.
Claim 4
Dependent Claim
34 words
The method according to claim 1, in which supermicrogranular silica is added to the coating solution in an amount of 0.25 to 2 grams per 100 cc. of a water dispersion of colloidal silica.
Claim 5
Independent Claim
150 words
A method for producing an oriented silicon steel sheet with a surface film which improves iron loss and magnetostriction characteristic of the steel sheet, comprising the steps of forming a glassy film on the oriented silicon steel sheet by a reaction with an annealing separating agent during a high temperature finishing annealing of said steel sheet, thereupon applying to this glassy film a coating solution composed of 4 to 16 wt. percent of colloidal silica, 3 to 24 wt. percent of aluminum phosphate, calculated as aluminum biphosphate, and 0.2 to 4.5 wt. percent of at least one compound selected from the group consisting of chromic anhydride and chromate, baking the thus applied coating solution at a temperature above 350*C and then subjecting the steel sheet to a heat-treatment in a temperature range of from 800* to 900*C after or during the said application of the coating solution and baking thereof.
Claim 6
Independent Claim
150 words
A method for producing an oriented silicon steel sheet with a surface film which improves iron loss and magnetostriction characteristic of the steel sheet, comprising the steps of forming a glassy film on the oriented silicon steel sheet by a reaction with an annealing separating agent during a high temperature finishing annealing of said steel sheet, thereupon applying to this glassy film a coating solution composed of 4 to 16 wt. percent of colloidal silica, 3 to 24 wt. percent of aluminum phosphate, calculated as aluminum biphosphate, and 0.2 to 4.5 wt. percent of at least one compound selected from the group consisting of chromic anhydride and chromate, baking the thus applied coating solution at a temperature above 350*C and then subjecting the steel sheet to a heat-treatment in a temperature range of from 800* to 900*C after or during the said application of the coating solution and baking thereof.
Claim 7
Dependent Claim
66 words
The method for producing an oriented silicon steel sheet with a surface film which improves iron loss and magneto-striction characteristics of the steel sheet, according to claim 4, in which the glassy film formed on the surface of the steel sheet during the high temperature finishing annealing is removed by a pickling and then the coating solution is applied to the surface of the steel sheet.
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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) | 1977-12-23 | 1978-06-24 | 1978-12-24 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1981-12-23 | 1982-06-24 | 1982-12-24 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1985-12-23 | 1986-06-24 | 1986-12-24 | $7700.00 | Window Closed / Lapsed |