US3857740A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Precipitation hardening high strength cold rolled steel sheet and method for producing same
Assignee: Nippon Steel Corp
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Filing: 1973-07-09
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Granted: 1974-12-31
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Expires: 1993-07-09
Abstract
Abstract A precipitation hardening high strength cold rolled steel sheet comprising 0.03 to 0.25% C, not more than 1.5% Si, 0.6 to 2.5% Mn, 0.01 to 0.15% Al, 0.01 to 0.40% effective Ti (total Ti% - 3.4[N%] - 1.5[0%] - 1.5 [S%]) and satisfying 4[C%] - 0.6% < effective Ti% < 4[C%], with the balance being Fe and unavoidable imparities.
Inventors
- 👤 H Gondo
- 👤 H Takechi
- 👤 H Masui
- 👤 K Ozaki
- 👤 T Kawano
- 👤 K Namba
- 👤 K Sakurai
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-30 22:36
CPC Classifications
C; C21; C21D; C21D8/00; C21D8/02; C21D8/04; C21D8/0421; C21D8/0426; C22; C22C; C22C38/00; C22C38/04; C22C38/14; C21D8/0436; C21D8/0447; C21D8/0473
Claims Analysis
Total Claims: 5
Claim 1
Independent Claim
126 words
A METHOD FOR PRODUCING A PRECIPITATION HARDENING HIGH STRENGTH COLD ROLLED STEEL SHEET COMPRISING HEATING A STEEL SLAB CONTAINING 0.03 TO 0.25% C, NOT MORE THAN 1.5% SI, 0.6 TO 2.5% MN, 0.01 TO 0.15% AL, 0.01 TO 0.40% EFFECTIVE TI (TOTAL (TI%)-34(N%)-1.5((0%)-1.5(S%) AND SATISFYING THE CONDITION OF F(C%)-0.6%<EFFECTIVE TI% <4(C%), WITH BALANCE BEING FE AND UNAVOIDABLE IMPURITIES AT A TEMPERATURE NOT LOWER THAN 1, 2::=C, HOT ROLLING THE SLAB, SUBJECTING THE HOT ROLLED SHEET TO A FINISHING ROLLING AT A TEMPRATURE NOT LOWER THAN 870*C, COILING THE SHEET, COLD ROLLING THE SHEET WITH AND 680*C, ACID PICKLING THE SHEET, COLD ROOLING THE SHEET WITH A REDUCTION RATE NOT LESS THAN 30% AND SUBJECTING THE SHEET TO RECRYSTALLIZATION ANNEALING AT A TEMPERATURE BETWEEN 600* AND 900*C.
Claim 2
Independent Claim
126 words
A METHOD FOR PRODUCING A PRECIPITATION HARDENING HIGH STRENGTH COLD ROLLED STEEL SHEET COMPRISING HEATING A STEEL SLAB CONTAINING 0.03 TO 0.25% C, NOT MORE THAN 1.5% SI, 0.6 TO 2.5% MN, 0.01 TO 0.15% AL, 0.01 TO 0.40% EFFECTIVE TI (TOTAL (TI%)-34(N%)-1.5((0%)-1.5(S%) AND SATISFYING THE CONDITION OF F(C%)-0.6%<EFFECTIVE TI% <4(C%), WITH BALANCE BEING FE AND UNAVOIDABLE IMPURITIES AT A TEMPERATURE NOT LOWER THAN 1, 2::=C, HOT ROLLING THE SLAB, SUBJECTING THE HOT ROLLED SHEET TO A FINISHING ROLLING AT A TEMPRATURE NOT LOWER THAN 870*C, COILING THE SHEET, COLD ROLLING THE SHEET WITH AND 680*C, ACID PICKLING THE SHEET, COLD ROOLING THE SHEET WITH A REDUCTION RATE NOT LESS THAN 30% AND SUBJECTING THE SHEET TO RECRYSTALLIZATION ANNEALING AT A TEMPERATURE BETWEEN 600* AND 900*C.
Claim 3
Dependent Claim
21 words
A process according to claim 1 in which the temperature of the recrystallization annealing is higher than the hot coiling temperature.
Claim 4
Dependent Claim
38 words
A process according to claim 1 in which the sheet after the recrystallization annealing is again cold rolled with a reduction rate not less than 30% and subjected to recrystallization annealing at a temperature between 600* and 900*C.
Claim 5
Dependent Claim
91 words
A method as claimed in claim 1, wherein said steel slab further comprises at least one element selected from at least one of Groups A, B and C in a total amount of 0.01 to 0.1% for Group A elements, 0.03 to 1.0% for Group B elements and 0.01 to 0.1% of actually added amount for Group C elements, said Group A consisting of Nb, V, Mo and W, said Group B consisting of Cr, Ni and Cu, and said Group C consisting of Zr, Ca, Mg and rare earth elements.
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) | 1977-12-30 | 1978-07-01 | 1978-12-31 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1981-12-30 | 1982-07-01 | 1982-12-31 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1985-12-30 | 1986-07-01 | 1986-12-31 | $7700.00 | Window Closed / Lapsed |