Grain-oriented electrical steel sheet and method for manufacturing same

Patent metadata

Field	Value
Publication number	US-12512240-B2
Application number	US-202218283162-A
Country	US
Kind code	B2
Filing date	Mar 28, 2022
Priority date	Mar 26, 2021
Publication date	Dec 30, 2025
Grant date	Dec 30, 2025

Abstract

This grain-oriented electrical steel sheet includes a base steel sheet, a glass coating formed on the base steel sheet, and a tension-applied insulation coating formed on the glass coating, in which, in the base steel sheet, a plurality of linear strain regions that extend continuously or intermittently in a direction intersecting with a rolling direction are present, the plurality of linear strain regions are each 210 μm or less in width in the rolling direction, the plurality of linear strain regions are parallel to each other, intervals of linear strain regions adjacent to each other in the rolling direction are 10 mm or less, and magnetostriction λ 0-pb in a unit of μm/m when the grain-oriented electrical steel sheet is excited up to 1.7 T and magnetostriction λ 0-pa in a unit of μm/m when the grain-oriented electrical steel sheet is heat-treated at 800° C. for 4 hours and then excited up to 1.7 T satisfy 0.02≤λ 0-pb −λ 0-pa ≤0.20.

First claim

What is claimed is:

1 . A grain-oriented electrical steel sheet comprising:
a base steel sheet; a glass coating formed on the base steel sheet; and a tension-applied insulation coating formed on the glass coating, wherein, in the base steel sheet, a plurality of linear strain regions that extend continuously or intermittently in a direction intersecting with a rolling direction are present, the plurality of linear strain regions are each 210 μm or less in width in the rolling direction, the plurality of linear strain regions are parallel to each other, intervals of linear strain regions adjacent to each other in the rolling direction are 10 mm or less, and magnetostriction λ 0-pb in a unit of μm/m when the grain-oriented electrical steel sheet is excited up to 1.7 T and magnetostriction λ 0-pa in a unit of μm/m when the grain-oriented electrical steel sheet is heat-treated at 800° C. for 4 hours and then excited up to 1.7 T satisfy the following expression (1),
0.02≤λ 0-pb −λ 0-pa ≤0.20  (1).

2 . The grain-oriented electrical steel sheet according to claim 1 ,
wherein the glass coating is formed of a structure including a Mg 2 SiO 4 phase that is a primary phase and a MgAl 2 O 4 phase, and in a cross section in a sheet thickness direction, when the glass coating is divided into three regions having an equal thickness in the sheet thickness direction, each region is designated as a 1/3 region, a 2/3 region, and a 3/3 region from a base steel sheet side toward a tension-applied insulation coating side, an area ratio of the MgAl 2 O 4 phase in the 1/3 region is denoted by S1, an area ratio of the MgAl 2 O 4 phase in the 2/3 region is denoted by S2, and an area ratio of the MgAl 2 O 4 phase in the 3/3 region is denoted by S3, the S1, the S2, and the S3 satisfy the following expressions (2) to (4),
S 1> S 2> S 3  (2)

( S 1+ S 2+ S 3)/3<0.50  (3)

S 3<0.10  (4).

3 . A method for manufacturing the grain-oriented electrical steel sheet according to claim 1 , the method comprising:
a hot rolling step of heating a steel piece to obtain a hot-rolled steel sheet by hot rolling; a hot-rolled sheet annealing step of performing hot-rolled sheet annealing on the hot-rolled steel sheet; a pickling step of pickling the hot-rolled steel sheet after the hot-rolled sheet annealing step; a cold rolling step of performing cold rolling once or a plurality of times with annealing therebetween on the hot-rolled steel sheet after the pickling step to obtain a cold-rolled steel sheet; a decarburization annealing step of performing decarburization annealing on the cold-rolled steel sheet; a final annealing step of applying and drying an annealing separating agent containing a MgO powder as a main component onto front and rear surfaces of the cold-rolled steel sheet after the decarburization annealing step, which is the base steel sheet, and performing final annealing to form glass coatings; a coating-forming step of forming tension-applied insulation coatings on the glass coatings to obtain a grain-oriented electrical steel sheet including the base steel sheet, the glass coatings formed on the base steel sheet, and the tension-applied insulation coatings formed on the glass coatings; and a magnetic domain segmentation step of irradiating surfaces of the tension-applied insulation coatings of the grain-oriented electrical steel sheet with an energy ray to form a plurality of linear strain regions on the base steel sheet, wherein, in the magnetic domain segmentation step, among the plurality of linear strain regions, intervals of linear strain regions adjacent to each other in a rolling direction are 10 mm or less, an energy ray power density Ip in a unit of W/mm 2 that is defined by (P/S) using an energy ray output P in a unit of W and an energy ray irradiation cross-sectional area S in a unit of mm 2 satisfies the following expression (5), an energy ray input energy Up in a unit of J/mm that is defined by P/Vs using the energy ray output P and an energy ray scanning velocity Vs in a unit of mm/sec satisfies the following expression (6), and a beam aspect ratio of the energy ray, which is defined by (dl/dc) using a diameter dl in a direction perpendicular to a beam scanning direction and a diameter dc in the beam scanning direction, in a unit of μm, and the dl each satisfy the following expression (7) and the following expression (8),
250≤ Ip≤ 2,000  Expression (5)

0.010< Up≤ 0.050  Expression (6)

0.0010< dl/dc< 1.0000  (7)

10< dl< 200  (8).

4 . The method for manufacturing the grain-oriented electrical steel sheet according to claim 3 ,
wherein the energy ray is a laser beam.

5 . The method for manufacturing the grain-oriented electrical steel sheet according to claim 4 ,
wherein the laser beam is a fiber laser beam.

6 . The method for manufacturing the grain-oriented electrical steel sheet according to claim 3 ,
wherein the steel piece contains, by mass %, C: 0.010% to 0.200%, Si: 3.00% to 4.00%, sol. Al: 0.010% to 0.040%, Mn: 0.01% to 0.50%, N: 0.020% or less, S: 0.005% to 0.040%, P: 0.030% or less, Cu: 0% to 0.50%, Cr: 0% to 0.50%, Sn: 0% to 0.50%, Se: 0% to 0.020%, Sb: 0% to 0.500%, and Mo: 0% to 0.10%, and a remainder is Fe and impurities.

7 . The method for manufacturing the grain-oriented electrical steel sheet according to claim 3 ,
wherein the decarburization annealing step has a temperature raising process and a soaking process, in the temperature raising process, a temperature rising rate from 550° C. to 750° C. is set to 700 to 2,000° C./sec, an oxygen potential is set to 0.0001 to 0.0100, and the soaking process includes a first soaking process where an annealing temperature is set to 800° C. to 900° C. and an annealing time is set to 100 to 500 seconds in an atmosphere having an oxygen potential of 0.4 or more and 0.8 or less and a second soaking process where an annealing temperature is set to 850° C. or higher and 1,000° C. or lower and an annealing time is set to 5 seconds or longer and 100 seconds or shorter in an atmosphere having an oxygen potential of 0.1 or less.

8 . The method for manufacturing the grain-oriented electrical steel sheet according to claim 3 , the method further comprising, during the decarburization annealing step or after the decarburization annealing step:
a nitriding treatment step of performing a nitriding treatment on the cold-rolled steel sheet.

9 . A method for manufacturing the grain-oriented electrical steel sheet according to claim 2 , the method comprising:
a hot rolling step of heating a steel piece to obtain a hot-rolled steel sheet by hot rolling; a hot-rolled sheet annealing step of performing hot-rolled sheet annealing on the hot-rolled steel sheet; a pickling step of pickling the hot-rolled steel sheet after the hot-rolled sheet annealing step; a cold rolling step of performing cold rolling once or a plurality of times with annealing therebetween on the hot-rolled steel sheet after the pickling step to obtain a cold-rolled steel sheet; a decarburization annealing step of performing decarburization annealing on the cold-rolled steel sheet; a final annealing step of applying and drying an annealing separating agent containing a MgO powder as a main component onto front and rear surfaces of the cold-rolled steel sheet after the decarburization annealing step, which is the base steel sheet, and performing final annealing to form glass coatings; a coating-forming step of forming tension-applied insulation coatings on the glass coatings to obtain a grain-oriented electrical steel sheet including the base steel sheet, the glass coatings formed on the base steel sheet, and the tension-applied insulat

Assignees

• Nippon Steel Corp

Inventors

• IWAKI Masataka
• Kataoka Takashi
• Tanaka Tomohito
• Hamamura Hideyuki

Classifications

• C23D13/00

  After-treatment of the enamelled articles · CPC title

• C23D5/04

  by dry methods · CPC title

• C23D3/00

  Chemical treatment of the metal surfaces prior to coating · CPC title

• C22C2202/02

  Magnetic · CPC title

• C22C38/60

  containing lead, selenium, tellurium, or antimony, or more than 0.04% by weight of sulfur · CPC title