# US 11,898,215 B2 · Grain-oriented electrical steel sheet and method for manufacturing the same

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- Number: US 11,898,215 B2
- Document ID: US11898215B2
- Status: Granted
- Kind: B2
- Application number: 17/421,850
- Filed: 2020-01-16
- Published: 2022-04-07
- Granted: 2024-02-13
- Earliest claimed: 2019-01-16
- Assignees: Nippon Steel Corporation
- Applicants: Nippon Steel Corporation
- Inventors: Yoshiyuki Ushigami; Shinji Yamamoto; Fumiaki Takahashi; Hideyuki Hamamura; Shinsuke Takatani; Masaru Takahashi
- Web page: https://patentgrep.com/patent/US11898215B2

## CPC

- C21D 1/76: Adjusting the composition of the atmosphere
- C21D 8/1283: {Application of a separating or insulating coating}
- C21D 1/26: Methods of annealing
- C21D 6/005: {containing Mn}
- C21D 6/008: {containing Si}
- C21D 8/1222: {Hot rolling}
- C21D 8/1233: {Cold rolling}
- C21D 8/1261: {following hot rolling}
- C21D 8/1272: {Final recrystallisation annealing}
- C21D 9/46: for sheet metals
- C21D 10/00: Modifying the physical properties by methods other than heat treatment or deformation
- C22C 38/001: {containing N}
- C22C 38/002: {containing In, Mg, or other elements not provided for in one single group C22C38/001 - C22C38/60}
- C22C 38/02: containing silicon
- C22C 38/04: containing manganese
- C22C 38/06: containing aluminium
- C23C 22/08: Orthophosphates
- C23C 22/20: containing aluminium cations
- C23C 22/22: containing alkaline earth metal cations
- C23C 22/33: containing also phosphates
- C23C 22/74: for obtaining burned-in conversion coatings
- H01F 1/147: Alloys characterised by their composition {(treatment thereof for enhancing their electromagnetic properties C21D8/12)}
- H01F 1/18: with insulating coating
- C21D 2201/05: Grain orientation
- C22C 38/60: containing lead, selenium, tellurium, or antimony, or more than 0.04% by weight of sulfur
- C22C 2202/02: Magnetic
- C21D: MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING (surface treatment of metallic material involving at least one process provided for in class C23 and at least one process covered by this subclass C23F17/00; unidirectional solidification of eutectic materials or unidirectional demixing of eutectoid materials C30B)
- C22C: ALLOYS (treatment of alloys C21D, C22F)
- C23C: COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THE SURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL (making metal-coated products by extrusion B21C23/22; covering with metal by connecting pre-existing layers to articles, see the relevant places, e.g. B21D39/00, B23K; metallising of glass C03C; metallising mortars, concrete, artificial stone, ceramics or natural stone C04B41/00; enamelling of, or applying a vitreous layer to, metals C23D; treating metal surfaces or coating of metals by electrolysis or electrophoresis C25D; single-crystal film growth C30B; by metallising textiles D06M11/83; decorating textiles by locally metallising D06Q1/04)
- H01F: MAGNETS; INDUCTANCES; TRANSFORMERS; SELECTION OF MATERIALS FOR THEIR MAGNETIC PROPERTIES

## Abstract

The grain-oriented electrical steel sheet according to the present invention is a grain-oriented electrical steel sheet having a base steel sheet (1), an intermediate layer (4) disposed to be in contact with the base steel sheet (1), and an insulation coating (3) disposed to be in contact with the intermediate layer (4), and the grain-oriented electrical steel sheet includes a surface of the base steel sheet (1) having a groove (G) which extends in a direction intersecting a rolling direction of the base steel sheet (1), in which in a cross-sectional view of a plane parallel to the rolling direction and a sheet thickness direction of the base steel sheet (1), when a region between end portions of the groove (G) is defined as a groove part (RG), an average thickness of the intermediate layer (4) of the groove part (RG) is 0.5 times or more and 3.0 times or less an average thickness of the intermediate layer (4) other than the groove part (RG), and an area ratio of voids in the insulation coating (3) of the groove part (RG) is 15% or less.

## Claims

### Claim 1

A grain-oriented electrical steel sheet having a base steel sheet, an intermediate layer having silicon oxide as a main component disposed to be in contact with the base steel sheet, and an insulation coating disposed to be in contact with the intermediate layer, the grain-oriented electrical steel sheet comprising:
a surface of the base steel sheet has a groove which extends in a direction intersecting a rolling direction of the base steel sheet, wherein
in a cross-sectional view of a plane parallel to the rolling direction and a sheet thickness direction of the base steel sheet, when a region between end portions of the groove is defined as a groove part,
an average thickness of the intermediate layer of the groove part is 0.5 times or more and 3.0 times or less an average thickness of the intermediate layer other than the groove part, and
an area ratio of voids in the insulation coating of the groove part is 15% or less.

### Claim 2 (depends on 1)

The grain-oriented electrical steel sheet according to claim 1, wherein,
in the cross-sectional view, when an internally oxidized part having a maximum depth of 0.2 μm or more present in the base steel sheet of the groove part is represented by a line segment ratio at an interface between the base steel sheet and the intermediate layer, the internally oxidized part is present at 15% or less.

### Claim 3 (depends on 1)

The grain-oriented electrical steel sheet according to claim 1, wherein, in the cross-sectional view, a depth of the base steel sheet from the surface of the base steel sheet other than the groove part to a bottom portion of the groove part in the sheet thickness direction of the base steel sheet is 15 μm or more and 40 μm or less.

### Claim 4 (depends on 1)

The grain-oriented electrical steel sheet according to claim 1, wherein, in the cross-sectional view,
an average thickness of the insulation coating other than the groove part is 0.1 μm or more and 10 μm or less, and
the depth of the base steel sheet from a surface of the insulation coating of the groove part to the bottom portion of the groove part in the sheet thickness direction of the base steel sheet is 15.1 μm or more and 50 μm or less.

### Claim 5 (depends on 1)

The grain-oriented electrical steel sheet according to claim 1, wherein the groove is provided continuously or discontinuously when seen in a direction perpendicular to a sheet surface of the base steel sheet.

### Claim 6 (depends on 1)

A method for manufacturing the grain-oriented electrical steel sheet according to claim 1, the method comprising:
forming a groove in the base steel sheet which does not have a forsterite film and has a texture developed in a {110}<001> orientation at any stage after cold rolling and before the insulation coating is formed on the base steel sheet; and
forming the intermediate layer and the insulation coating on the base steel sheet after the groove is formed,
wherein, in the forming of the insulation coating,
an insulation coating forming solution is applied to the base steel sheet, and the base steel sheet is soaked in a temperature range of 800° C. or higher and 1000° C. or lower for 10 seconds or more and 120 seconds or less in an atmosphere gas containing hydrogen and nitrogen and having an oxidation degree of PH2O/PH2 adjusted to 0.001 or more and 0.15 or less, and
the soaked base steel sheet is cooled to 500° C. at a cooling rate of 5° C./sec or more and 30° C./sec or less.

### Claim 7 (depends on 1)

A method for manufacturing the grain-oriented electrical steel sheet according to claim 1, the method comprising:
forming the intermediate layer and the insulation coating on the base steel sheet which does not have a forsterite film and has a texture developed in a {110}<001> orientation;
forming a groove in the base steel sheet on which the intermediate layer and the insulation coating are formed; and
further forming the intermediate layer and the insulation coating on the base steel sheet in which the groove is formed,
wherein, in at least the final forming of the insulation coating,
an insulation coating forming solution is applied to the base steel sheet, and the base steel sheet is soaked in a temperature range of 800° C. or higher and 1000° C. or lower for 10 seconds or more and 120 seconds or less in an atmosphere gas containing hydrogen and nitrogen and having an oxidation degree of PH2O/PH2 adjusted to 0.001 or more and 0.15 or less, and
the soaked base steel sheet is cooled to 500° C. at a cooling rate of 5° C./sec or more and 30° C./sec or less.