Patent US2499764A successfully refreshed from Google Patents.
US2499764A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Processing stainless steel
Assignee: Armco Inc
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Filing: 1945-11-24
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Granted: 1950-03-07
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Expires: 1965-11-24
Abstract
No abstract record available.
Inventors
- 👤 Philip G Mabus
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-28 20:10
CPC Classifications
C; C21; C21D; C21D1/00; C21D1/68; C21D1/70
Claims Analysis
Total Claims: 1
Claim 1
Independent Claim
68 words
THE METHOD OF HEAT-TREATING STAINLESS STEEL IN THE SUBSTANTIAL ABSENCE OF DETRIMENTAL SCALE FORMATION, COMPRISING IN COMBINATION, THE STEPS OF CONVERTING A SURFACE LAYER OF THE METAL TO THE BLACK OXIDE THEREOF BY IMMERSION IN A BATH CONSISTING OF ONE OR BOTH OF THE GROUP MOLTEN SODIUM DICHROMATE AND MOLTEN POTASSIUM DICHROMATE, THEREUPON HEAT-TREATING THE METAL AT ELEVATED TEMPERATURES AND IN OXIDIZING ATMOSPHERE ORDINARILY CAUSING SCALE FORMATION, AND
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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) | 1953-03-06 | 1953-09-05 | 1954-03-07 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1957-03-06 | 1957-09-05 | 1958-03-07 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1961-03-06 | 1961-09-05 | 1962-03-07 | $7700.00 | Window Closed / Lapsed |