Patent US2851387A successfully refreshed from Google Patents.
US2851387A
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Method of depassifying high chromium steels prior to nitriding
Assignee: Chapman Valve Manufacturing Co
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Filing: 1957-05-08
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Granted: 1958-09-09
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Expires: 1977-05-08
Abstract
No abstract record available.
Inventors
- 👤 Low Sidney
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-29 16:27
CPC Classifications
C; C23; C23G; C23G5/00; C23C; C23C8/00; C23C8/02; C23C8/06; C23C8/08; C23C8/24; C23C8/26
Claims Analysis
Total Claims: 2
Claim 1
Independent Claim
69 words
IN A METHOD OF CONDITIONING CHROMIUM STEEL FOR A NITRIDING TREATMENT, THE ART WHICH INCLUDES, HEATING THE STEEL WITHIN A SUFFICIENTLY HIGH TEMPERATURE RANGE IN THE PRESSURE OF THE GASEOUS DERIVATIVES OF A FLOUROCARBON AND THE REMOVAL OF THE CHROMIUM OXIDE FILM ON THE STEEL SURFACE, AND FURTHER HEATING THE STEEL WITHIN A SUFFICIENTLY HIGH TEMPERATURE RANGE AND FOR A SUFFICIENTLY LONG PERIOD OF TIME IN A NITOGEOUS ATMOSPHERE.
Claim 2
Dependent Claim
69 words
IN A METHOD OF CONDITIONING CHROMIUM STEEL FOR A NITRIDING TREATMENT, THE ART WHICH INCLUDES, HEATING THE STEEL WITHIN A SUFFICIENTLY HIGH TEMPERATURE RANGE IN THE PRESSURE OF THE GASEOUS DERIVATIVES OF A FLOUROCARBON AND THE REMOVAL OF THE CHROMIUM OXIDE FILM ON THE STEEL SURFACE, AND FURTHER HEATING THE STEEL WITHIN A SUFFICIENTLY HIGH TEMPERATURE RANGE AND FOR A SUFFICIENTLY LONG PERIOD OF TIME IN A NITOGEOUS ATMOSPHERE.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1961-09-08 | 1962-03-10 | 1962-09-09 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1965-09-08 | 1966-03-10 | 1966-09-09 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1969-09-08 | 1970-03-10 | 1970-09-09 | $7700.00 | Window Closed / Lapsed |