Grain-oriented magnetic steel sheet and method of producing the same

Patent metadata

Field	Value
Publication number	US-10131018-B2
Application number	US-201314390110-A
Country	US
Kind code	B2
Filing date	Apr 24, 2013
Priority date	Apr 27, 2012
Publication date	Nov 20, 2018
Grant date	Nov 20, 2018

Abstract

A grain-oriented magnetic steel sheet includes grooves each of which extends in a direction intersecting a transportation direction, the grooves being formed at predetermined pitches PL in the transportation direction by laser beam irradiation, in which a relationship between a standard deviation value D and the pitch PL satisfies the following expression (1), the standard deviation value D being a standard deviation of distances between a linear approximation line, which is obtained from a center line of each of the grooves in a groove width direction by a least-squares method, and respective positions on the center line, and an average angle formed between tangent lines of the respective positions on the center line and a direction perpendicular to the transportation direction is more than 0° to 30°.

[Expression 1]

0.02≤( D/PL )  (1)

First claim

The invention claimed is:

1. A grain-oriented magnetic steel sheet comprising
grooves each of which extends in a direction intersecting a transportation direction, the grooves being formed at predetermined pitches PL in the transportation direction by laser beam irradiation,
wherein a melt-resolidified portion is formed in the grooves,
wherein each of the grooves is formed to be curved in a length L c when viewed from a direction perpendicular to a surface of the grain-oriented magnetic steel sheet,
wherein multiple grooves are formed in the direction intersecting the transportation direction, and
wherein
a relationship between a standard deviation value D which is defined by the following expression (2) and the pitch PL satisfies the following expression (1), the standard deviation value D being a standard deviation of distances between a linear approximation line, which is obtained from a center line of each of the grooves in a groove width direction by a least-squares method, and respective positions on the center line, and
an average angle formed between tangent lines of the respective positions on the center line and a direction perpendicular to the transportation direction is more than 0° to 30°

0.02
≤

(

D
/
PL

)

(
1
)

D
=

1

L
C

⁢

∫
0

L
C

⁢

d
⁢

⁢
X
⁢


Y


2

(
2
)

wherein X is an axis which represents a direction of a linear approximation line C and Y is an axis which represents a direction perpendicular to the linear approximation line C, and
when a curve of each of the grooves is expressed by a function of y=f(x) in a coordination system in which an x axis represents a direction perpendicular to the transportation direction of the grain-oriented magnetic steel sheet and a y axis represents the transportation direction, the linear approximation line C with respect to the curve of each of the grooves which is expressed by y=ax+b is obtained using a least-squares method.

2. The grain-oriented magnetic steel sheet according to claim 1 ,
wherein the grooves are formed on a front surface and a back surface of the grain-oriented magnetic steel sheet.

3. The grain-oriented magnetic steel sheet according to claim 2 ,
wherein positions of the grooves formed on the front surface are the same as positions of the grooves formed on the back surface.

4. A method of producing a grain-oriented magnetic steel sheet, the method comprising:
irradiating a grain-oriented magnetic steel sheet with a laser beam to form grooves, each of which extends in a direction intersecting a transportation direction, at predetermined pitches PL in the transportation direction,
wherein a melt-resolidified portion is formed in the grooves,
wherein each of the grooves is formed to be curved in a length L c when viewed from a direction perpendicular to a surface of the grain-oriented magnetic steel sheet,
wherein multiple grooves are formed in the direction intersecting the transportation direction, and
wherein
a relationship between a standard deviation value D which is defined by the following expression (2) and the pitch PL satisfies the following expression (1), the standard deviation value D being a standard deviation of distances between a linear approximation line, which is obtained from a center line of each of the grooves in a groove width direction by a least-squares method, and respective positions on the center line, and
an average angle formed between tangent lines of the respective positions on the center line and a direction perpendicular to the transportation direction is more than 0° to 30°

0.02
≤

(

D
/
PL

)

(
1
)

D
=

1

L
C

⁢

∫
0

L
C

⁢

d
⁢

⁢
X
⁢


Y


2

(
2
)

wherein X is an axis which represents a direction of a linear approximation line

Assignees

• Nippon Steel & Sumitomo Metal Corp

Inventors

• Hirano Koji
• Arai Satoshi
• Hamamura Hideyuki
• Imai Hirofumi

Classifications

• H01F1/16

  in the form of sheets (H01F1/147 takes precedence) · CPC title

• C21D8/12

  during manufacturing of articles with special electromagnetic properties · CPC title

• C22C38/02

  containing silicon · CPC title

• B23K26/0821 Primary

  using multifaceted mirrors, e.g. polygonal mirror · CPC title

• C21D8/1277 Primary

  involving a particular surface treatment (C21D8/1294 takes precedence) · CPC title