US3490956A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Method of producing ferritic stainless steel
Assignee: Allegheny Ludlum Corp
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Filing: 1965-06-03
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Granted: 1970-01-20
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Expires: 1985-06-03
Abstract
No abstract record available.
Inventors
- 👤 Joseph W Wilton
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-03 02:05
CPC Classifications
C; C21; C21D; C21D8/00; C21D8/02; C21D8/04; C22; C22C; C22C38/00; C22C38/18
Claims Analysis
Total Claims: 2
Claim 1
Independent Claim
215 words
THE METHOD OF PRODUCING A FERRITIC STAINLESS STEEL, CHARACTERIZED BY A REDUCED TENDENCY TO EXHIBIT RIBBING AND ROPING UPON DEEP DRAWING, HAVING A COMPOSITION CONSISTING ESSENTIALLY OF UP TO 0.12% CARBON, UP TO 1.0% MANGANESE, UP TO 1.0% SILICON, FROM 12% TO 22% CHROMIUM, UP TO 0.5* NICKEL, UP TO 2.5% MOLYBDENUM, FROM 0.10% TO 0.50% VANADIUM, FROM 0.05% TO 0.40% ZIRCONIUM, UP TO 0.50% COPPER AND THE BALANCE ESSENTIALLY IRON WITH INCIDENTAL IMPURITIES, WHICH COMPRISES (A) HOT ROLLING THE STEEL TO AN INTERMEDIATE GAUGE HAVING A THICKNESS WITHIN THE RANGE BETWEEN ABOUT 0.100 AND 0.300 INCH, (B) BOX ANNEALING THE STEEL AT A TEMPERATURE WITHIN THE RANGE BETWEEN ABOUT 1500*F. AND ABOUT 1675* F., (C) DESCALING THE STEEL, (D) COLD ROLLING THE STEEL TO EFFECT A REDUCTION OF BE TWEEN ABOUT 40% AND ABOUT 80% IN CROSS-SECTIONAL AREA, (E) NORMALIZING THE STEEL AT A TEMPERATURE WITHIN THE RANGE BETWEEN ABOUT 1600*F. AND ABOUT 2100*F IN AN ATMOSPHERE WHICH PREVENTS OXIDATION, NITRIDING AND CARBURIZING OF THE STEEL SURFACE FOR A TIME PERIOD SUFFICIENT TO EFFECT RECOVERY AND RECRYSTALLIZATION BUT NOT TO EXCEED 60 MINUTES PER INCH OF STEEL THICKNESS, (F) COLD ROLLING THE STEEL TO FINISH GAUGE, AND (G) RECRYSTALLIZATION ANNEALING THE STEEL AT A TEMPERATURE WITHIN THE RANGE BETWEEN ABOUT 1450*F. AND ABOUT 1600*F.
Claim 2
Independent Claim
215 words
THE METHOD OF PRODUCING A FERRITIC STAINLESS STEEL, CHARACTERIZED BY A REDUCED TENDENCY TO EXHIBIT RIBBING AND ROPING UPON DEEP DRAWING, HAVING A COMPOSITION CONSISTING ESSENTIALLY OF UP TO 0.12% CARBON, UP TO 1.0% MANGANESE, UP TO 1.0% SILICON, FROM 12% TO 22% CHROMIUM, UP TO 0.5* NICKEL, UP TO 2.5% MOLYBDENUM, FROM 0.10% TO 0.50% VANADIUM, FROM 0.05% TO 0.40% ZIRCONIUM, UP TO 0.50% COPPER AND THE BALANCE ESSENTIALLY IRON WITH INCIDENTAL IMPURITIES, WHICH COMPRISES (A) HOT ROLLING THE STEEL TO AN INTERMEDIATE GAUGE HAVING A THICKNESS WITHIN THE RANGE BETWEEN ABOUT 0.100 AND 0.300 INCH, (B) BOX ANNEALING THE STEEL AT A TEMPERATURE WITHIN THE RANGE BETWEEN ABOUT 1500*F. AND ABOUT 1675* F., (C) DESCALING THE STEEL, (D) COLD ROLLING THE STEEL TO EFFECT A REDUCTION OF BE TWEEN ABOUT 40% AND ABOUT 80% IN CROSS-SECTIONAL AREA, (E) NORMALIZING THE STEEL AT A TEMPERATURE WITHIN THE RANGE BETWEEN ABOUT 1600*F. AND ABOUT 2100*F IN AN ATMOSPHERE WHICH PREVENTS OXIDATION, NITRIDING AND CARBURIZING OF THE STEEL SURFACE FOR A TIME PERIOD SUFFICIENT TO EFFECT RECOVERY AND RECRYSTALLIZATION BUT NOT TO EXCEED 60 MINUTES PER INCH OF STEEL THICKNESS, (F) COLD ROLLING THE STEEL TO FINISH GAUGE, AND (G) RECRYSTALLIZATION ANNEALING THE STEEL AT A TEMPERATURE WITHIN THE RANGE BETWEEN ABOUT 1450*F. AND ABOUT 1600*F.
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) | 1973-01-19 | 1973-07-21 | 1974-01-20 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1977-01-19 | 1977-07-21 | 1978-01-20 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1981-01-19 | 1981-07-21 | 1982-01-20 | $7700.00 | Window Closed / Lapsed |