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US5049205A
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Process for preparing unidirectional silicon steel sheet having high magnetic flux density
Assignee: Nippon Steel Corp
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Filing: 1990-09-27
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Granted: 1991-09-17
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Expires: 2010-09-27
Abstract
Abstract The present invention relates to a process for preparing a unidirectional silicon steel sheet having a high magnetic flux density which comprises heating a silicon steel slab comprising by weight 0.025 to 0.075% of carbon, 2.5 to 4.5% of silicon, 0.015% or less of sulfur, 0.010 to 0.050% of acid-soluble aluminum, 0.0010 to 0.012% of nitrogen, 0.050 to 0.45% of manganese and 0.01 to 0.10% of tin and optionally 0.0005 to 0.0080% of boron with the balance being iron and unavoidable impurities, at 1200° C. or below; hot-rolling the slab; subjecting the slab to rolling once or two or more times wherein intermediate annealing is provided, thereby attaining a percentage final rolling of 80% or more; subjecting the resultant steel sheet to decarburizing annealing in a wet hydrogen atmosphere; coating the steel sheet with an annealing separator; conducting finishing annealing for secondary recrystallization and purification of the steel; and subjecting the steel sheet to a nitriding treatment between after the ignition for decarburizing annealing and before the initiation of the secondary recrystallization in the finishing annealing.
Inventors
- 👤 Nobuyuki Takahashi
- 👤 Katsuro Kuroki
- 👤 Yozo Suga
- 👤 Kiyoshi Ueno
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-09 04:45
CPC Classifications
C; C21; C21D; C21D8/00; C21D8/12; C21D8/1244; C21D8/1255; C22; C22C; C22C38/00; C22C38/02; C21D3/00; C21D3/02; C21D3/04; C21D8/1216; C21D8/1233; C21D8/1277; C21D8/1283
Claims Analysis
Total Claims: 6
Claim 1
Independent Claim
165 words
A process for preparing a unidirectional silicon steel sheet having a high magnetic flux density which comprises heating a silicon steel slab comprising by weight 0.025 to 0.075% of carbon, 2.5 to 4.5% of silicon, 0.015% or less of sulfur, 0.010 to 0.050% of acid-soluble aluminum, 0.0010 to 0.012% of nitrogen, 0.050 to 0.45% of manganese and 0.01 to 0.10% of tin with the balance being iron and unavoidable impurities, at 1200° C. or below; hot-rolling the slab; subjecting the slab to rolling once or two or more times wherein an intermediate annealing is provided, thereby attaining a percentage final rolling of 80% or more; subjecting the resultant steel sheet to decarburizing annealing in a wet hydrogen atmosphere; coating the steel sheet with an annealing separator; conducting finishing annealing for secondary recrystallization and purification of the steel; and subjecting the steel sheet to a nitriding treatment between after the ignition for decarburizing annealing and before the initiation of the secondary recrystallization in the finishing annealing.
Claim 2
Dependent Claim
165 words
A process for preparing a unidirectional silicon steel sheet having a high magnetic flux density which comprises heating a silicon steel slab comprising by weight 0.025 to 0.075% of carbon, 2.5 to 4.5% of silicon, 0.015% or less of sulfur, 0.010 to 0.050% of acid-soluble aluminum, 0.0010 to 0.012% of nitrogen, 0.050 to 0.45% of manganese and 0.01 to 0.10% of tin with the balance being iron and unavoidable impurities, at 1200° C. or below; hot-rolling the slab; subjecting the slab to rolling once or two or more times wherein an intermediate annealing is provided, thereby attaining a percentage final rolling of 80% or more; subjecting the resultant steel sheet to decarburizing annealing in a wet hydrogen atmosphere; coating the steel sheet with an annealing separator; conducting finishing annealing for secondary recrystallization and purification of the steel; and subjecting the steel sheet to a nitriding treatment between after the ignition for decarburizing annealing and before the initiation of the secondary recrystallization in the finishing annealing.
Claim 3
Dependent Claim
169 words
A process for preparing a unidirectional silicon steel sheet having a high magnetic flux density which comprises heating a silicon steel slab comprising by weight 0.025 to 0.075% of carbon, 2.5 to 4.5% of silicon, 0.015% or less of sulfur, 0.010 to 0.050% of acid-soluble aluminum, 0.0010 to 0.012% of nitrogen, 0.050 to 0.45% of manganese, 0.0005 to 0.0080% of boron and 0.01 to 0.10% of tin with the balance being iron and unavoidable impurities, at 1200° C. or below; hot-rolling the slab; subjecting the slab to rolling once or two or more times wherein intermediate annealing is provided, thereby attaining a percentage final rolling of 80% or more; subjecting the resultant steel sheet to decarburizing annealing in a wet hydrogen atmosphere; coating the steel sheet with an annealing separator; conducting finishing annealing for secondary recrystallization and purification of the steel; and subjecting the steel sheet to a nitriding treatment between after the ignition for decarburizing annealing and before the initiation of the secondary recrystallization in the finishing annealing.
Claim 4
Dependent Claim
169 words
A process for preparing a unidirectional silicon steel sheet having a high magnetic flux density which comprises heating a silicon steel slab comprising by weight 0.025 to 0.075% of carbon, 2.5 to 4.5% of silicon, 0.015% or less of sulfur, 0.010 to 0.050% of acid-soluble aluminum, 0.0010 to 0.012% of nitrogen, 0.050 to 0.45% of manganese, 0.0005 to 0.0080% of boron and 0.01 to 0.10% of tin with the balance being iron and unavoidable impurities, at 1200° C. or below; hot-rolling the slab; subjecting the slab to rolling once or two or more times wherein intermediate annealing is provided, thereby attaining a percentage final rolling of 80% or more; subjecting the resultant steel sheet to decarburizing annealing in a wet hydrogen atmosphere; coating the steel sheet with an annealing separator; conducting finishing annealing for secondary recrystallization and purification of the steel; and subjecting the steel sheet to a nitriding treatment between after the ignition for decarburizing annealing and before the initiation of the secondary recrystallization in the finishing annealing.
Claim 5
Dependent Claim
43 words
A process according to claim 1, wherein the oxygen content of the steel sheet after decarburizing annealing is regulated to ppm after conversion into a value for a sheet thickness of 12 mil =55t ±50 wherein t is the sheet thickness in mil.
Claim 6
Dependent Claim
43 words
A process according to claim 2, wherein the oxygen content of the steel sheet after decarburizing annealing is regulated to ppm after conversion into a value for a sheet thickness of 12 mil =55t ±50 wherein t is the sheet thickness in mil.
References Cited (Backward Citations)
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| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
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| 3.5 Years (Year 4) | 1994-09-16 | 1995-03-18 | 1995-09-17 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1998-09-16 | 1999-03-18 | 1999-09-17 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2002-09-16 | 2003-03-18 | 2003-09-17 | $7700.00 | Window Closed / Lapsed |