Grain-oriented electrical steel sheet, finish annealing-use steel sheet, annealing separator, method for manufacturing grain-oriented electrical steel sheet, and method for manufacturing finish annealing-use steel sheet

Patent metadata

Field	Value
Publication number	US-12454735-B2
Application number	US-202217901936-A
Country	US
Kind code	B2
Filing date	Sep 2, 2022
Priority date	Jan 8, 2019
Publication date	Oct 28, 2025
Grant date	Oct 28, 2025

Abstract

Grain-oriented electrical steel sheet excellent in magnetic properties and adhesion of a primary coating to a base steel sheet and with few defects where the base metal is exposed in point defects and a method for manufacturing grain-oriented electrical steel sheet are provided. This is characterized by being provided with a base steel sheet and a primary coating. The primary coating satisfies (1) Number density D3 of Al concentrated regions: 0.015 to 0.150/μm 2 (2) (Area S5 of regions comprised of anchoring oxide layer regions and Al concentrated regions)/(area S3 of Al concentrated regions)≥0.30, (3) Distance H5 of mean value of heights in thickness direction of regions of comprised of anchoring oxide layer regions and Al concentrated regions minus H0: 0.4 to 4.0 μm, (4) (Perimeter L5 of regions comprised of anchoring oxide layer regions and Al concentrated regions)/(observed area S0): 0.020 to 0.500 μm/μ 2 , and (5) (Area S1 of anchoring oxide layer regions)/(observed area S0)≥0.15.

First claim

The invention claimed is:

1. A grain-oriented electrical steel sheet comprising
a base steel sheet having a chemical composition comprising, by mass %,
C: 0.0050% or less,
Si: 2.5 to 4.5%,
Mn: 0.02 to 0.20%,
one or more elements of S and Se: total of 0.005% or less,
sol. Al: 0.010% or less, and
N: 0.010% or less and

having a balance comprised of Fe and impurities and
a primary coating formed on a surface of the base steel sheet and comprising 50 mass % or more of Mg 2 SiO 4 , where,
uneven-shape information of a surface of the primary coating when designating a direction from a primary coating side toward the base steel sheet in a thickness direction of the base steel sheet as positive is laid out projected on a plane parallel to the surface of the steel sheet,
when designating a center value of a surface height of the primary coating as H0, the primary coating existing at the base steel sheet side from H0+0.2 μm is prescribed as an “anchoring oxide layer region” and the primary coating existing at the primary coating side from H0+0.2 μm is prescribed as a “surface oxide layer region”, and,
in a correlation distribution chart of a characteristic X-ray intensity laying out constituent information in the primary coating projected on the plane parallel to the surface of the steel sheet and uneven shape, a maximum value of the characteristic X-ray intensity of Al is identified and a region where a characteristic X-ray intensity of Al is 20% or more of the maximum value of the characteristic X-ray intensity of Al is defined as an “Al concentrated region”,
the primary coating satisfies the conditions of
(1) Number density D3 of Al concentrated regions: 0.015 to 0.150/μm 2 ,
(2) (Area S5 of regions which is anchoring oxide layer regions and is also Al concentrated regions)/(area S3 of Al concentrated regions)≥0.30,
(3) Distance H5 of mean value of heights in thickness direction of regions, which is anchoring oxide layer regions and is also AL concentrated regions, minus H0: 0.4 to 4.0 μm,
(4) (Perimeter L5 of regions which is anchoring oxide layer regions and is also Al concentrated regions)/(observed area S0): 0.020 to 0.500 μm/μm 2 ,
(5) (Area S1 of anchoring oxide layer regions)/(observed area S0)≥0.15.

2. The grain-oriented electrical steel sheet according to claim 1 , wherein
the primary coating comprises one or more elements of Y, La, and Ce and one or more elements of Ca, Sr, and Ba, and,
when, in the correlation distribution chart of characteristic X-ray intensity and uneven shape, maximum values of characteristic X-ray intensities of Ca, Sr, and Ba are identified and a region where a characteristic X-ray intensity of Ca is 20% or more of the maximum value of the characteristic X-ray intensity of Ca, a region where a characteristic X-ray intensity of Sr is 20% or more of the maximum value of the characteristic X-ray intensity of Sr, and a region where a characteristic X-ray intensity of Ba is 20% or more of the maximum value of the characteristic X-ray intensity of Ba are together defined as “Ca group element concentrated regions”,
the primary coating satisfies the conditions of
(6) Ratio of total content of the one or more elements of Y, La, and Ce to the content of Mg 2 SiO 4 in the primary coating: 0.1 to 6.0%,
(7) Ratio of total content of the one or more elements of Ca, Sr, and Ba to the content of Mg 2 SiO 4 in the primary coating: 0.1 to 6.0%,
(8) Number density D4 of Ca group element concentrated regions: 0.005 to 2.000/μm 2 .

Assignees

• Nippon Steel Corp

Inventors

• Yamagata Ryutaro
• Morishige Nobusato
• Tanaka Ichiro

Classifications

• C22C38/16

  containing copper · CPC title

• H01F1/14775

  in the form of sheets · CPC title

• C21D6/005

  containing Mn · CPC title

• C21D6/008

  containing Si · CPC title

• C21D8/1283

  Application of a separating or insulating coating · CPC title