US3814636A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Method for production of low carbon steel with high drawability and retarded aging characteristics
Assignee: United States Steel Corp
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Filing: 1972-03-02
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Granted: 1974-06-04
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Expires: 1992-03-02
Abstract
Abstract A SHEET STEEL WITH EXCEPTIONALLY HIGH DRAWABILITY AND RETARDED AGING CHARACTERISTICS IS PRODUCED BY ADJUSTING THE MELT TO LESS THAN 0.50% MN, 0.002 TO 0.06%C, LESS THAN 150 P.P.M. OXYGEN AND ADDING CB TO COMBINE WITH THE C AND N PRESENT IN THE MELT. THE SLAB CAST FROM THE MELT IS THEN HOT ROLLED ABOVE THE A3 TEMPERATURE AND HEAT-TREATED TO PRODUCE A CRITICAL COARSE DISPERSION OF CARBONITRIDES. THE RESULTANT SHEET IS THEN COLD REDUCED FROM 50 TO 90% AND SOAKED AT TEMPERATURES WITHIN THE RANGE 1200*F TO THE FERRITE TO AUSTENITE TRANSFORMATION TEMPERATURE OF THE STEEL TO DEVELOP DESIRED CRYSTALLOGRAPHIC TEXTURES.
Inventors
- 👤 P Mould
- 👤 J Gray
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-05 21:07
CPC Classifications
C; C21; C21D; C21D8/00; C21D8/02; C21D8/04; C21D8/0421; C21D8/0426; C21D8/0436; C21D8/0447; C21D8/0473
Claims Analysis
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References Cited (Backward Citations)
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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) | 1977-06-03 | 1977-12-03 | 1978-06-04 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1981-06-03 | 1981-12-03 | 1982-06-04 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1985-06-03 | 1985-12-03 | 1986-06-04 | $7700.00 | Window Closed / Lapsed |