US3756868A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Method of annealing steel coils moving through a furnace
Assignee: Allegheny Ludlum Corp
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Filing: 1971-05-04
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Granted: 1973-09-04
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Expires: 1991-05-04
Abstract
Abstract A FURNACE FOR ANNEALING WHOLE COILS OF SILICON STEEL WHICH INCLUDES A WELDED GAS TIGHT SHELL LINED WITH VARYING THICKNESS REFRACTORY MATERIAL DEFINING A PLURALITY OF INDEPENDENTLY CONTROLLABLE HEATING AND COOLING ZONES AND IN WHICH A HYDROGEN ATMOSPHERE IS MAINTAINED; THE FURNACE HAVING CARS OF SPECIAL DESIGN FOR TRANSPORTING THE COILS THERETHROUGH, SPECIAL HEATING ELEMENTS EXTENDING ALONG THE FURNACE WALLS OF THE HEATING ZONE AND A SUPPLEMENTAL COOLING ARRANGEMENT FOR THE COILS TO PROVIDE A CONTROLLED HEAT TREATMENT.
Inventors
- 👤 W Bloom
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-29 17:35
CPC Classifications
C; C21; C21D; C21D1/00; C21D1/74
Claims Analysis
Total Claims: 0
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References Cited (Backward Citations)
No citation records indexed.
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1976-09-03 | 1977-03-05 | 1977-09-04 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1980-09-03 | 1981-03-05 | 1981-09-04 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1984-09-03 | 1985-03-05 | 1985-09-04 | $7700.00 | Window Closed / Lapsed |