US3971678A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Method of making cold-rolled sheet for electrical purposes
Assignee: Stahlwerke Pein Salzgitter AG
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Filing: 1974-06-20
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Granted: 1976-07-27
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Expires: 1994-06-20
Abstract
Abstract Alloy steel sheeting for electrical purposes such as the cores of transformers, is made with isotropic magnetic properties by a method in which steel containing, by weight, up to 0.1% carbon, from 0.15 to 0.35% manganese, from 0.3 to 2.4% aluminium up to 0.25% copper, up to 0.5% sulphur, up to 0.2% phosphorus, up to 2.0% silicon and the balance iron except for impurities is hot rolled at a temperature of from 820° to 1080°C to cause at least 5% of it to have a crystal orientation {100} <hkl>. After this the sheet is cold-rolled with a reduction in cross-section of from 50% to 85% and then it is recrystallization-annealed at a temperature of from 820° to 1200°C. Preferably the cold-rolling is carried out in two stages and the sheet is annealed for from 10 to 30 minutes at a temperature of from 550° to 950°C between the two stages.
Inventors
- 👤 Constantin Vlad
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-27 22:53
CPC Classifications
C; C22; C22C; C22C38/00; C22C38/06; C21; C21D; C21D8/00; C21D8/12; C21D8/1216; C21D8/1233; H; H01; H01F; H01F1/00; H01F1/01; H01F1/03; H01F1/12; H01F1/14; H01F1/16; C21D8/1222; C21D8/1244; C21D8/1266; C21D8/1272
Claims Analysis
Total Claims: 7
Claim 1
Independent Claim
133 words
A method of making cold-rolled sheet for electrical purposes, said sheet having isotropic magnetic properties, said method comprising the steps of hot rolling at a temperature of from 820° to 1080°C a steel consisting essentially of up to 0.1% carbon, from 0.15% to 0.35% manganese, from 0.3% to 2.4% aluminium, up to 0.25% copper, up to 0.05% sulphur, up to 0.2% phosphorus, up to 2.0% silicon and the balance iron except for impurities, to bring at least 5% of the grains into a {100} <hkl> - orientation, cold-rolling said sheet with a reduction in cross section of from 50% to 85% and subsequently recrystallisation-annealing said sheet at a temperature of from 820° to 1200°C. for a time sufficient to yield a product having a grain length at least five times the sheet thickness.
Claim 2
Independent Claim
133 words
A method of making cold-rolled sheet for electrical purposes, said sheet having isotropic magnetic properties, said method comprising the steps of hot rolling at a temperature of from 820° to 1080°C a steel consisting essentially of up to 0.1% carbon, from 0.15% to 0.35% manganese, from 0.3% to 2.4% aluminium, up to 0.25% copper, up to 0.05% sulphur, up to 0.2% phosphorus, up to 2.0% silicon and the balance iron except for impurities, to bring at least 5% of the grains into a {100} <hkl> - orientation, cold-rolling said sheet with a reduction in cross section of from 50% to 85% and subsequently recrystallisation-annealing said sheet at a temperature of from 820° to 1200°C. for a time sufficient to yield a product having a grain length at least five times the sheet thickness.
Claim 3
Dependent Claim
26 words
A method as claimed in claim 1, further comprising the step of reeling said sheet at a temperature of less than 720°C after said hot rolling.
Claim 4
Dependent Claim
19 words
A method as claimed in claim 1, further comprising the step of normalising said sheet after said hot rolling.
Claim 5
Dependent Claim
27 words
A method as claimed in claim 1, further comprising the step of decarburisation-normalising said sheet with said sheet possessing scale as a result of said hot rolling.
Claim 6
Dependent Claim
43 words
A method as claimed in claim 1, wherein said cold-rolling is carried out in two stages and further comprising the step of annealing said sheet for from 10 to 30 minutes at a temperature of from 550° to 950°C between said two stages.
Claim 7
Dependent Claim
29 words
A method as claimed in claim 1, wherein said cold-rolling is carried out in two stages, and further comprising the step of decarburisation-annealing said sheet between said two stages.
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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) | 1979-07-27 | 1980-01-26 | 1980-07-27 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1983-07-27 | 1984-01-26 | 1984-07-27 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1987-07-27 | 1988-01-26 | 1988-07-27 | $7700.00 | Window Closed / Lapsed |