US4092178A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Process for producing a steel having excellent strength and toughness
Assignee: Nippon Steel Corp
•
Filing: 1975-12-05
•
Granted: 1978-05-30
•
Expires: 1995-12-05
Abstract
Abstract A process for producing a steel having excellent strength and toughness, which comprises continuously casting a molten steel containing 0.01 - 0.10% Al and 0.002 - 0.009% N with an average cooling rate of not lower than 3 DEG C/min. down to 500 DEG C to obtain a steel slab heating the steel slab to a temperature ranging from 900 DEG to 1150 DEG C and rolling the steel slab.
Inventors
- 👤 Yasumitsu Onoe
- 👤 Yoshikazu Matsumura
- 👤 Hiroshi Katoh
- 👤 Koe Nakajima
- 👤 Shozo Sekino
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-05 00:15
CPC Classifications
B; B22; B22D; B22D11/00; C; C21; C21D; C21D8/00; C21D8/02; C21D8/021; C22; C22C; C22C38/00; C22C38/06
Claims Analysis
Total Claims: 3
Claim 1
Independent Claim
121 words
A process for producing a low alloy steel of fine grain structure containing 0.01-0.10% Al and 0.002-0.009% N and having excellent strength and toughness by a continuous casting process, which comprises continuously casting a molten steel having said composition to obtain a steel slab, cooling said steel slab to 500° C with an average cooling rate of not lower than 3° C/min., so as to prevent the precipitation of AlN, maintaining the slab temperature as cooled and reheating said slab for hot rolling to a relatively low temperature range from 900° to 1150° C so as to precipitate fine AlN while preventing the growth of austenite grains by accelerating the formation of AlN nuclei prior to the formation of austenite nuclei.
Claim 2
Dependent Claim
121 words
A process for producing a low alloy steel of fine grain structure containing 0.01-0.10% Al and 0.002-0.009% N and having excellent strength and toughness by a continuous casting process, which comprises continuously casting a molten steel having said composition to obtain a steel slab, cooling said steel slab to 500° C with an average cooling rate of not lower than 3° C/min., so as to prevent the precipitation of AlN, maintaining the slab temperature as cooled and reheating said slab for hot rolling to a relatively low temperature range from 900° to 1150° C so as to precipitate fine AlN while preventing the growth of austenite grains by accelerating the formation of AlN nuclei prior to the formation of austenite nuclei.
Claim 3
Dependent Claim
53 words
A process for producing a steel having excellent strength and toughness according to claim 1, in which the average cooling rate down to 500° C is not lower than 6° C/min. to obtain a steel slab containing nitrogen which precipitates as AlN in an amount not larger than 40% of the total nitrogen.
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) | 1981-05-29 | 1981-11-28 | 1982-05-30 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1985-05-29 | 1985-11-28 | 1986-05-30 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1989-05-29 | 1989-11-28 | 1990-05-30 | $7700.00 | Window Closed / Lapsed |