Patent US2289138A successfully refreshed from Google Patents.
US2289138A
Expired / Lapsed
US
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Method of hardening steel
Assignee: United States Steel Corp
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Filing: 1939-08-03
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Granted: 1942-07-07
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Expires: 1959-08-03
Abstract
No abstract record available.
Inventors
- 👤 Warren H Mayo
- 👤 Harold J Elmendorf
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-09 08:05
CPC Classifications
C; C21; C21D; C21D1/00; C21D1/68; C21D1/70
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) | 1945-07-06 | 1946-01-05 | 1946-07-07 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1949-07-06 | 1950-01-05 | 1950-07-07 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1953-07-06 | 1954-01-05 | 1954-07-07 | $7700.00 | Window Closed / Lapsed |