US3928087A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Method of strengthening low carbon steel and product thereof
Assignee: Armco Inc
•
Filing: 1974-05-30
•
Granted: 1975-12-23
•
Expires: 1994-05-30
Abstract
Abstract Deep drawing steel is strengthened by alloy-nitrogen precipitation strengthening to a minimum average yield strength of 50 ksi. A deoxidized, low carbon steel sheet stock or article formed therefrom, containing from about 0.02 to 0.2% titanium in solution, from about 0.025 to 0.3% columbium in solution, from about 0.025 to about 0.3% zirconium in solution, alone or in admixture, is heat treated at 1,100*-1,350*F in an atmosphere containing ammonia in an amount insufficient, at the temperature and time involved, to permit formation of iron nitride.
Inventors
- 👤 Rollin E Hook
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-26 14:47
CPC Classifications
C; C21; C21D; C21D8/00; C21D8/02; C21D8/04; C21D8/0447; C21D8/0457; C21D3/00; C21D3/02; C21D3/08; C21D8/0473
Claims Analysis
Total Claims: 4
Claim 1
Independent Claim
151 words
COLD REDUCED AND ANNEALED STEEL SHEET STOCK HAVING A THICKNESS BETWEEN ABOUT 0.02 INCH AND 0.09 INCH, AN AVERAGE YIELD STRENGTH OF AT LEAST 70 KSI, AND SUFFICIENT FORMABILITY TO PERMIT FABRICATION INTO ARTICLES OTHER THAN DEEP DRAWN, CONSISTING ESSENTIALLY OF LESS THAN ABOUT 0.010% CARBON, FROM ABOUT 0.05 TO ABOUT 0.6% MANGANESE, FROM ABOUT 0.02 TO ABOUT 0.04% TOTAL ALUMINUM, UP TO ABOUT 0.035% SULFUR, UP TO ABOUT 0.01% OXYGEN, RESIDUAL SILICON AND PHOSPHORUS, AT LEAST ONE NITRIDE-FORMING ELEMENT CHOSEN FROM THE GROUP CONSISTING OF TITANIUM, TITANIUM AND COLUMBIUM, TITANIUM AND ZIRCONIUM, AND TITANIUM AND MIXTURES OF COLUMBIUM AND ZIRCONIUM, WITH TOTAL TITANIUM RANGING BETWEEN ABOUT 0.08 AND 0.10 PERCENT, TOTAL COLUMBIUM RANGING BETWEEN ABOUT 0.03 AND 0.06 PERCENT, TOTAL ZIRCONIUM RANGING BETWEEN ABOUT 0.03 AND 0.06 PERCENT, SUFFICIENT NITROGEN TO COMBINE SUBSTANTIALLY COMPLETELY WITH SAID ALUMINUM AND SAID NITRIDE-FORMING ELEMENTS, AND REMAINDER ESSENTIALLY IRON, ALL PERCENTAGES BEING BY WEIGHT.
Claim 2
Dependent Claim
151 words
COLD REDUCED AND ANNEALED STEEL SHEET STOCK HAVING A THICKNESS BETWEEN ABOUT 0.02 INCH AND 0.09 INCH, AN AVERAGE YIELD STRENGTH OF AT LEAST 70 KSI, AND SUFFICIENT FORMABILITY TO PERMIT FABRICATION INTO ARTICLES OTHER THAN DEEP DRAWN, CONSISTING ESSENTIALLY OF LESS THAN ABOUT 0.010% CARBON, FROM ABOUT 0.05 TO ABOUT 0.6% MANGANESE, FROM ABOUT 0.02 TO ABOUT 0.04% TOTAL ALUMINUM, UP TO ABOUT 0.035% SULFUR, UP TO ABOUT 0.01% OXYGEN, RESIDUAL SILICON AND PHOSPHORUS, AT LEAST ONE NITRIDE-FORMING ELEMENT CHOSEN FROM THE GROUP CONSISTING OF TITANIUM, TITANIUM AND COLUMBIUM, TITANIUM AND ZIRCONIUM, AND TITANIUM AND MIXTURES OF COLUMBIUM AND ZIRCONIUM, WITH TOTAL TITANIUM RANGING BETWEEN ABOUT 0.08 AND 0.10 PERCENT, TOTAL COLUMBIUM RANGING BETWEEN ABOUT 0.03 AND 0.06 PERCENT, TOTAL ZIRCONIUM RANGING BETWEEN ABOUT 0.03 AND 0.06 PERCENT, SUFFICIENT NITROGEN TO COMBINE SUBSTANTIALLY COMPLETELY WITH SAID ALUMINUM AND SAID NITRIDE-FORMING ELEMENTS, AND REMAINDER ESSENTIALLY IRON, ALL PERCENTAGES BEING BY WEIGHT.
Claim 3
Dependent Claim
140 words
A deep drawn article formed from a cold-reduced and annealed steel sheet stock consisting essentially of less than about 0.010% carbon, from about 0.05 to about 0.6% manganese, from about 0.02 to about 0.04% total aluminum, up to about 0.035% sulfur, up to about 0.01% oxygen, residual silicon and phosphorus, at least one nitride forming element chosen from the group consisting of titanium, titanium and columbium, titanium and zirconium, and titanium and mixtures of columbium and zirconium, with total titanium ranging between about 0.08 and 0.10 percent, total columbium ranging between about 0.03 and 0.06 percent, total zirconium ranging between about 0.03 and 0.06 percent, sufficient nitrogen to combine substantially completely with said aluminum and said nitride-forming elements, and remainder essentially iron, all percentages being by weight, said article having an average yield strength of at least about 50 ksi.
Claim 4
Dependent Claim
140 words
A deep drawn article formed from a cold-reduced and annealed steel sheet stock consisting essentially of less than about 0.010% carbon, from about 0.05 to about 0.6% manganese, from about 0.02 to about 0.04% total aluminum, up to about 0.035% sulfur, up to about 0.01% oxygen, residual silicon and phosphorus, at least one nitride forming element chosen from the group consisting of titanium, titanium and columbium, titanium and zirconium, and titanium and mixtures of columbium and zirconium, with total titanium ranging between about 0.08 and 0.10 percent, total columbium ranging between about 0.03 and 0.06 percent, total zirconium ranging between about 0.03 and 0.06 percent, sufficient nitrogen to combine substantially completely with said aluminum and said nitride-forming elements, and remainder essentially iron, all percentages being by weight, said article having an average yield strength of at least about 50 ksi.
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) | 1978-12-22 | 1979-06-23 | 1979-12-23 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1982-12-22 | 1983-06-23 | 1983-12-23 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1986-12-22 | 1987-06-23 | 1987-12-23 | $7700.00 | Window Closed / Lapsed |