Patent US2903635A successfully refreshed from Google Patents.
Patent US3711342A successfully refreshed from Google Patents.
US3711342A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Method of heat treating steel strip
Assignee: Surface Combustion Corp
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Filing: 1969-05-23
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Granted: 1973-01-16
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Expires: 1989-05-23
Abstract
Abstract THIS DISCLOSURE RELATES TO A METHOD FOR HEAT TREATING WORK HARDENED STEEL STRIP WHICH HAS BEEN COLD REDUCED 40 TO 80 PERCENT AND CONTAINS FROM 0.04 TO 0.1 PERCENT CARBON. THE STRIP IS RAPIDLY HEATED TO A TEMPERATURE TO WHICH AUSTENITE AND FERRITE EXIST UNDER EQUILIBRIUM CONDITIONS SO THAT IT RETAINS APPRECIABLE WORK STRESSES WHEN IT REACHES TEMPERATURE. THE STRIP IS THEN MAINTAINED AT SUCH TEMPERATURE UNTIL THE WORK STRESS IS RELIEVED, AND THEN IS HEATED TO A SECOND TEMPERATURE AT WHICH ONLY AUSTENITE EXISTS UNDER EQUILIBRIUM CONDITIONS. THE STRIP IS MAINTAINED AT THE SECOND TEMPERATURE UNTIL UNIFORMITY OF GRAIN SIZE IS ACHIEVED, AFTER WHICH THE STRIP IS COOLED.
Inventors
- 👤 O Cullen
- 👤 J Lincoln
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-27 11:41
CPC Classifications
C; C21; C21D; C21D8/00; C21D8/02; C21D8/04; C21D8/0447; C21D8/0473; C21D9/00; C21D9/52; C21D8/0421; C21D8/0436
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) | 1976-01-16 | 1976-07-17 | 1977-01-16 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1980-01-16 | 1980-07-17 | 1981-01-16 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1984-01-16 | 1984-07-17 | 1985-01-16 | $7700.00 | Window Closed / Lapsed |