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US4493739A Expired / Lapsed US ⏱️ 0.0 years remaining

Process for producing a grain-oriented electromagnetic steel sheet or strip having a low watt loss and a grain-oriented electromagnetic steel strip having uniform magnetic properties

Assignee: Nippon Steel Corp
•
Filing: 1982-08-04
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Granted: 1985-01-15
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Expires: 2002-08-04
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Abstract

Abstract In the production of a grain-oriented electromagnetic steel strip or sheet having a low watt loss, a silicon steel slab containing not more than 0.085% by weight of carbon, from 2.0% to 4.0% by weight of silicon, from 0.030% to 0.090% by weight of manganese, and from 0.010% to 0.060% by weight of sulfur is conventionally hot-rolled, cold-rolled, and final-annealed. However, this production process involves some problems in regard to the uniformity of the magnetic properties along the full length of the coiled strip. According to the present invention, a silicon steel slab additionally contains from 0.02% to 0.2% by weight of copper, the exit temperature during the finishing-hot-rolling step is controlled in such a manner that the temperature of the top portion of the hot-rolled strip is in the range of from 900 DEG C. to 1050 DEG C. and the temperature of the middle and bottom portions thereof is in the range of from 950 DEG C. and 1150 DEG C., and final cold-rolling is carried out at a reduction ratio of from 50% to 80%, with the result that the final product has good and very uniform magnetic properties over the full length thereof.

Inventors

  • 👤 Koichi Fujiwara
  • 👤 Tomohiko Sakai
  • 👤 Yoneo Yamada
  • 👤 Kazutaka Higashine

Bibliographic Details

Application Number —
Jurisdiction US
Data Source google_patents
Last Synchronized 2026-11-09 05:19
CPC Classifications
C; C21; C21D; C21D8/00; C21D8/12; C21D8/1216; C21D8/1222

Claims Analysis

Total Claims: 7
Claim 1
Independent Claim 173 words
A process for producing a grain-oriented electromagnetic steel sheet or strip having a low watt loss, wherein: a silicon steel slab containing not more than 0.085% by weight of carbon, from 2.0% to 4.0% by weight of silicon, from 0.030% to 0.090% by weight of manganese, and from 0.010% to 0.060% by weight of sulfur, the balance being essentially iron and unavoidable impurities, is hot-rolled, cold-rolled and final-annealed, wherein final cold-rolling is carried out at a reduction ratio of from 50% to 80%; said silicon steel slab additionally contains from 0.02% to 0.2% by weight of copper; the exit temperature of the finishing-hot-rolling step is controlled so that the size of Cu 2 S particles formed by said copper and said sulfur is uniform along the full length of a hot-rolled strip; and temperature of the top portion of the hot-rolled strip is in the range of from 900° C. to 1050° C., and temperature of the middle and bottom portions thereof is in the range of from 950° C. to 1150° C.
Claim 2
Dependent Claim 173 words
A process for producing a grain-oriented electromagnetic steel sheet or strip having a low watt loss, wherein: a silicon steel slab containing not more than 0.085% by weight of carbon, from 2.0% to 4.0% by weight of silicon, from 0.030% to 0.090% by weight of manganese, and from 0.010% to 0.060% by weight of sulfur, the balance being essentially iron and unavoidable impurities, is hot-rolled, cold-rolled and final-annealed, wherein final cold-rolling is carried out at a reduction ratio of from 50% to 80%; said silicon steel slab additionally contains from 0.02% to 0.2% by weight of copper; the exit temperature of the finishing-hot-rolling step is controlled so that the size of Cu 2 S particles formed by said copper and said sulfur is uniform along the full length of a hot-rolled strip; and temperature of the top portion of the hot-rolled strip is in the range of from 900° C. to 1050° C., and temperature of the middle and bottom portions thereof is in the range of from 950° C. to 1150° C.
Claim 3
Dependent Claim 23 words
A process according to claim 1, characterized in that the entrance temperature of said finishing-hot-rolling step is from 1100° C. to 1250° C.
Claim 4
Dependent Claim 22 words
A process according to claim 2, characterized in that said temperature of said top portion is from 950° C. to 1000° C.
Claim 5
Dependent Claim 24 words
A process according to claim 2, characterized in that said temperature of said middle and bottom portions is from 1000° C. to 1100° C.
Claim 6
Dependent Claim 23 words
A process according to claim 1, characterized in that the phosphorus content in said silicon steel slab is 0.010% by weight or less.
Claim 7
Dependent Claim 24 words
A process according to claim 1 or 5, characterized in that said silicon steel slab contains not more than 0.1% by weight of tin.

References Cited (Backward Citations)

US2867557A Cited
US3239332A Cited
US3802937A Cited
JPS4869720A Cited
US3872704A Cited
US3855018A Cited
US3855018B1 Cited
US4212689A Cited
US4171994A Cited
US4371405A Cited

USPTO Annuity & Maintenance Windows

Annuity Stage Window Opens Payment Deadline Surcharge Period Until Estimated Fee Status
3.5 Years (Year 4) 1988-01-15 1988-07-16 1989-01-15 $2000.00 Window Closed / Lapsed
7.5 Years (Year 8) 1992-01-15 1992-07-16 1993-01-15 $3760.00 Window Closed / Lapsed
11.5 Years (Year 12) 1996-01-15 1996-07-16 1997-01-15 $7700.00 Window Closed / Lapsed

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