US3959033A
Expired / Lapsed
US
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Process for manufacturing silicon-aluminum steel sheet with oriented grains for magnetic applications, and products thus obtained
Assignee: Individual
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Filing: 1974-07-23
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Granted: 1976-05-25
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Expires: 1994-07-23
Abstract
Abstract Low carbon silicon-aluminum single-oriented steel sheet having high magnetic induction is produced by hot rolling at 1370°-1430°C., annealing from 10 to 60 seconds at 1050 to 1170°C., slow cooling to 700°-900°C., quenching from 700°-900°C., cold rolling with a reduction in thickness of 80 to 90%, recrystallization and decarburization annealing in wet hydrogen from 780° to 870°C. for 2 minutes, and final annealing at 1200°C. in a mixture of 10-50% hydrogen and 50-90% nitrogen. Cold rolling can be effected in two stages, the first stage to reduce the thickness by 20 to 50% followed by annealing at 700° to 900°C., quenching and final cold rolling with a reduction in thickness of 80 to 90%. The preferred temperature range prior to quenching, for one-step cold rolling, is 750° to 850°C.; and for two-step cold rolling, the first quench is preferably from a temperature of 750° to 850° C. and the second quench preferably from a temperature of 850° to 900°C.
Inventors
- 👤 Mario Barisoni
- 👤 Massimo Barteri
- 👤 Pietro Brozzo
- 👤 Edmondo Marianeschi
- 👤 Roberto Ricci Bitti
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-02 02:13
CPC Classifications
C; C21; C21D; C21D8/00; C21D8/12; C21D8/1244; C21D8/1261; C21D8/1216; C21D8/1233; C21D8/1266; C21D8/1272
Claims Analysis
Total Claims: 8
Claim 1
Independent Claim
197 words
In a process for making single-oriented silicon steel sheet material having high magnetic induction, comprising the steps of hot rolling silicon steel containing 2.5-3.5% Si, 0.01-0.05% Al., up to 0.06% C, balance essentially iron, annealing the hot rolled steel at 1050° to 1170°C., slow cooling the annealed steel to a predetermined temperature at a cooling rate that does not exceed 10°C. per second, quenching the steel from said predetermined temperature at a rate of 15° to 150°C. per second, cold rolling the steel in the as-quenched condition with a reduction in thickness of 80 to 90%, recrystallizing and decarburizing the steel by annealing the steel in a reducing atmosphere, and finally annealing the steel in an atmosphere consisting essentially of a mixture of nitrogen and hydrogen; the improvement in which said predetermined temperature is 700° to 900°C., the resulting steel having a high hardness phase, including at least one phase other than aluminum nitride, together with aluminum nitride, said high hardness phase having a microhardness of at least 600 HV, said high hardness phase being present in the quantity from 5 to 30% by volume, and the sheet having an average macrohardness of at least 230 HV.
Claim 2
Dependent Claim
197 words
In a process for making single-oriented silicon steel sheet material having high magnetic induction, comprising the steps of hot rolling silicon steel containing 2.5-3.5% Si, 0.01-0.05% Al., up to 0.06% C, balance essentially iron, annealing the hot rolled steel at 1050° to 1170°C., slow cooling the annealed steel to a predetermined temperature at a cooling rate that does not exceed 10°C. per second, quenching the steel from said predetermined temperature at a rate of 15° to 150°C. per second, cold rolling the steel in the as-quenched condition with a reduction in thickness of 80 to 90%, recrystallizing and decarburizing the steel by annealing the steel in a reducing atmosphere, and finally annealing the steel in an atmosphere consisting essentially of a mixture of nitrogen and hydrogen; the improvement in which said predetermined temperature is 700° to 900°C., the resulting steel having a high hardness phase, including at least one phase other than aluminum nitride, together with aluminum nitride, said high hardness phase having a microhardness of at least 600 HV, said high hardness phase being present in the quantity from 5 to 30% by volume, and the sheet having an average macrohardness of at least 230 HV.
Claim 3
Dependent Claim
16 words
The process as claimed in claim 1, in which said predetermined temperature is 750° to 850°C.
Claim 4
Dependent Claim
263 words
In a process for making single-oriented silicon steel sheet material having high magnetic induction, comprising the steps of hot rolling silicon steel containing 2.5-3.5% Si, 0.01-0.05% Al, up to 0.06% C, balance essentially iron, annealing the hot rolled steel at 1050° to 1170°C., slow cooling the annealed steel to a predetermined temperature at a cooling rate that does not exceed 10°C. per second, quenching the steel from said predetermined temperature at a rate of 15° to 150°C. per second, cold rolling the steel in the as-quenched condition with a reduction in thickness of 20 to 50%, annealing the steel at a further predetermined temperature, further cold rolling the steel with a reduction in thickness of 80 to 90%, recrystallizing and decarburizing the steel by annealing the steel in a reducing atmosphere, and finally annealing the steel in an atmosphere consisting essentially of a mixture of nitrogen and hydrogen; the improvement in which both said predetermined temperature and said further predetermined temperature are 700° to 900°C., and in which the steel is quenched from said further predetermined temperature prior to said further cold rolling at a rate of 15° to 150°C. per second and said further cold rolling is performed in the as-quenched condition, the resulting steel having a high hardness phase, including at least one phase other than aluminum nitride, together with aluminum nitride, said high hardness phase having a microhardness of at least 600 HV, said high hardness phase being present in the quantity from 5 to 30% by volume, and the sheet having an average macrohardness of at least 230 HV.
Claim 5
Dependent Claim
263 words
In a process for making single-oriented silicon steel sheet material having high magnetic induction, comprising the steps of hot rolling silicon steel containing 2.5-3.5% Si, 0.01-0.05% Al, up to 0.06% C, balance essentially iron, annealing the hot rolled steel at 1050° to 1170°C., slow cooling the annealed steel to a predetermined temperature at a cooling rate that does not exceed 10°C. per second, quenching the steel from said predetermined temperature at a rate of 15° to 150°C. per second, cold rolling the steel in the as-quenched condition with a reduction in thickness of 20 to 50%, annealing the steel at a further predetermined temperature, further cold rolling the steel with a reduction in thickness of 80 to 90%, recrystallizing and decarburizing the steel by annealing the steel in a reducing atmosphere, and finally annealing the steel in an atmosphere consisting essentially of a mixture of nitrogen and hydrogen; the improvement in which both said predetermined temperature and said further predetermined temperature are 700° to 900°C., and in which the steel is quenched from said further predetermined temperature prior to said further cold rolling at a rate of 15° to 150°C. per second and said further cold rolling is performed in the as-quenched condition, the resulting steel having a high hardness phase, including at least one phase other than aluminum nitride, together with aluminum nitride, said high hardness phase having a microhardness of at least 600 HV, said high hardness phase being present in the quantity from 5 to 30% by volume, and the sheet having an average macrohardness of at least 230 HV.
Claim 6
Dependent Claim
25 words
A process as claimed in claim 3, in which said predetermined temperature is 750° to 850°C. and said further predetermined temperature is 850° to 900°C.
Claim 7
Dependent Claim
12 words
Single-oriented silicon steel sheet material produced by the process of claim 1.
Claim 8
Dependent Claim
12 words
Single-oriented silicon steel sheet material produced by the process of claim 3.
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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) | 1979-05-25 | 1979-11-24 | 1980-05-25 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1983-05-25 | 1983-11-24 | 1984-05-25 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1987-05-25 | 1987-11-24 | 1988-05-25 | $7700.00 | Window Closed / Lapsed |