Grain-oriented electrical steel sheet and method for manufacturing the same

Patent metadata

Field	Value
Publication number	US-10535453-B2
Application number	US-201314439104-A
Country	US
Kind code	B2
Filing date	Oct 29, 2013
Priority date	Oct 31, 2012
Publication date	Jan 14, 2020
Grant date	Jan 14, 2020

Abstract

The present invention provides a grain-oriented electrical steel sheet with reduced iron loss over a wide range of sheet thickness by providing a grain-oriented electrical steel sheet with an actually measured sheet thickness t (mm) that includes a closure domain region extending linearly in a direction from 60° to 120° with respect to the rolling direction on a surface of the steel sheet, the closure domain region being formed periodically at a spacing s (mm) in the rolling direction, such that h≥74.9t+39.1 (0.26≥t), h≥897t−174.7 (t>0.26), (w×h)/(s×1000)≤−12.6t+7.9 (t>0.22), and (w×h)/(s×1000)≤−40.6t+14.1 (t≤0.22), where h (μm) is the depth and w (μm) is the width of the closure domain region.

First claim

The invention claimed is:

1. A grain-oriented electrical steel sheet with an actually measured sheet thickness t (mm), comprising a closure domain region extending linearly in a direction from 60° to 120° with respect to a rolling direction on a surface of the steel sheet, the closure domain region corresponding to a region of induced strain and being formed periodically at a spacing s (mm) in the rolling direction, wherein
w≥ 230 μm,

h≥ 168 t+ 29.0 (0.26≥ t ),

h≥ 1890 t− 418.7 ( t> 0.26),
( w×h )/( s× 1000)≤−12.3 t+ 6.9 ( t> 0.22), and

( w×h )/( s× 1000)≤−56.1 t+ 16.5 ( t≤ 0.22),

where h (μm) is a depth and w (μm) is a width of the closure domain region, s (mm) is the spacing, and t (mm) is the actually measured sheet thickness.

2. A method for manufacturing the grain-oriented electrical steel sheet with an actually measured sheet thickness t (mm) of claim 1 , comprising forming a closure domain region extending linearly in a direction from 60° to 120° with respect to a rolling direction on a surface of the steel sheet, the closure domain region corresponding to a region of induced stain and being formed periodically at a spacing s (mm) in the rolling direction, by using an electron beam emitted at an acceleration voltage Va (kV), wherein
w≥ 230 μm,

h≥ 168 t+ 29.0 (0.26≥ t ),

h≥ 1890 t− 418.7 ( t> 0.26),
( w×h )/( s× 1000)≤−12.3 t+ 6.9 ( t> 0.22), and

( w×h )/( s× 1000)≤−56.1 t+ 16.5 ( t≤ 0.22),

where h (μm) is a depth and w (μm) is a width of the closure domain region, s (mm) is the spacing, and t (mm) is the actually measured sheet thickness, and
Va≥ 580 t+ 270−6.7 P (0.26≥ t ),

Va≥ 6980 t− 1390−6.7 P ( t> 0.26), and

P> 45,

where P is irradiation energy per unit scanning length/beam diameter (J/m/mm).

3. The method of claim 2 , wherein the beam diameter of the electron beam is 400 μm or less.

4. The method of claim 2 , wherein a LaB 6 cathode is used as an irradiation source of the electron beam.

5. The method of claim 3 , wherein a LaB 6 cathode is used as an irradiation source of the electron beam.

Assignees

• Jfe Steel Corp

Inventors

• Takajo Shigehiro
• Inoue Hirotaka
• Okabe Seiji
• Hanazawa Kazuhiro

Classifications

• C21D2201/05

  Grain orientation · CPC title

• C21D8/1244

  characterised by the heat treatment · CPC title

• C21D1/38 Primary

  Heating by cathodic discharges · CPC title

• C21D8/12

  during manufacturing of articles with special electromagnetic properties · CPC title

• H01F1/16

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