Tough,high strength steel article
Abstract
Abstract STEEL ARTICLE, SUCH AS PLATE, HAVING A RELATIVELY HIGH YIELD STRENGTH, E.G. 70,000 P.S.I., TOGETHER WITH A RELATIVELY HIGH IMPACT RESISTANCE, E.G. 15 FOOT-POUND CHARPY V-NOTCH IMPACT TRANSITION TEMPERATURE IN THE RANGE -50* TO -100*F. OR LOWER. MICROSTRUCTURE IS FERRITE PLUS PEARLITE. FERRITIC GRAIN SIZE IS 9.5 ASTM OR FINER. COMPOSITION, IN WT. PERCENT: CARBON 0.02-0.26 MANGANESE 1.25-1.75 SILICON 0.75-1.5 NITROGEN 0.003-0.015 ALUMINUM 0.01-0.08 VANADIUM 0-0.07 COLUMBIUM 0-0.03 TUNGSTEN 0-0.1 ARTICLE IS HOT ROLLED WITH AT LEAST 25% DEFORMATION AT FINISHING TEMPERATURE ABOVE A1 TO GIVE MICROSTRUCTURE CONTAINING FINE GRAINED AUSTENITE (9.5 ASTM OR FINER). COOLING IS RAPID BUT CONTROLLED TO AVOID LOW TEMPERATURE TRANSFORMATION PRODUCTS IN MICROSTRUCTURE. NORMALIZING OPTIONAL.
Inventors
- 👤 William E Heitmann
- 👤 Frank Garofalo
Bibliographic Details
Claims Analysis
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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) | 1974-02-08 | 1974-08-10 | 1975-02-09 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1978-02-08 | 1978-08-10 | 1979-02-09 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1982-02-08 | 1982-08-10 | 1983-02-09 | $7700.00 | Window Closed / Lapsed |