# US 2025/0154631 A1 · Grain-oriented electrical steel sheet and method of production of same

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- Number: US 2025/0154631 A1
- Document ID: US20250154631A1
- Status: Published application
- Kind: A1
- Application number: 18/838,639
- Filed: 2023-04-04
- Published: 2025-05-15
- Earliest claimed: 2022-04-04
- Assignees: Nippon Steel Corporation
- Applicants: Nippon Steel Corporation
- Inventors: Masato YASUDA; Hideyuki HAMAMURA; Nobusato MORISHIGE; Masaru TAKAHASHI; Kimihiko SUGIYAMA
- Web page: https://patentgrep.com/patent/US20250154631A1

## CPC

- C22C 38/02: containing silicon
- H01F 1/16: in the form of sheets (H01F1/147 takes precedence)
- B23K 26/073: Shaping the laser spot
- B23K 26/364: for making a groove or trench, e.g. for scribing a break initiation groove
- C21D 6/008: {containing Si}
- C21D 8/12: during manufacturing of articles with special electromagnetic properties
- C21D 8/1222: {Hot rolling}
- C21D 8/1233: {Cold rolling}
- C21D 8/1261: {following hot rolling}
- C21D 8/1277: involving a particular surface treatment (C21D8/1294 takes precedence)
- C21D 8/1283: {Application of a separating or insulating coating}
- C21D 8/1288: {Application of a tension-inducing coating}
- C21D 8/1294: involving a localised treatment
- C21D 9/46: for sheet metals
- C21D 10/005: {by laser shock processing}
- C22C 38/001: {containing N}
- C22C 38/04: containing manganese
- C22C 38/06: containing aluminium
- H01F 1/147: Alloys characterised by their composition {(treatment thereof for enhancing their electromagnetic properties C21D8/12)}
- H01F 1/18: with insulating coating
- H01F 41/0233: {Manufacturing of magnetic circuits made from sheets (magnetic cores made from sheets H01F27/245; soft magnetic alloys in the form of sheets H01F1/16)}
- B23K 2101/34: Coated articles {; Surface treated articles}
- C21D 2201/05: Grain orientation
- Y02P 10/20: Recycling
- C22C: ALLOYS (treatment of alloys C21D, C22F)
- H01F: MAGNETS; INDUCTANCES; TRANSFORMERS; SELECTION OF MATERIALS FOR THEIR MAGNETIC PROPERTIES
- B23K: SOLDERING OR UNSOLDERING; WELDING; CLADDING OR PLATING BY SOLDERING OR WELDING; CUTTING BY APPLYING HEAT LOCALLY, e.g. FLAME CUTTING; WORKING BY LASER BEAM
- 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)
- Y02P: CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS

## Abstract

The present invention has as its object to provide grain-oriented electrical steel sheet better improved in core loss in control of magnetic domains for forming laser grooves in cold rolled steel sheet. The present invention provides grain-oriented electrical steel sheet meeting the following requirements for achieving the object: That is, it provides grain-oriented electrical steel sheet comprising a base material steel sheet having a plurality of grooves on its surface and a glass coating on the surface of the base material steel sheet, in which grain-oriented electrical steel sheet, an absolute value of an angle θ formed by a direction perpendicular to a rolling direction and a sheet thickness direction of the base material steel sheet and a longitudinal direction of the grooves is 0 to 40°, a width W of the grooves is 20 μm to 300 μm, a depth D of the grooves is 10 μm to 40 μm, and a pitch P of the grooves in the rolling direction is 1.0 mm to 30.0 mm, and, at an inside of the glass coating directly under surfaces of the recessed parts of the grooves, one or more fine grains of a long axis of 1 μm or more and 20 μm or less are present in a cross-section perpendicular to the longitudinal direction of the grooves.

## Claims

### Claim 1

Grain-oriented electrical steel sheet comprising a base material steel sheet having a plurality of grooves on its surface and a glass coating on the surface of the base material steel sheet, in which grain-oriented electrical steel sheet,
an angle θ formed by a direction perpendicular to a rolling direction and a sheet thickness direction of the base material steel sheet and a longitudinal direction of the grooves is 40° or less, a width W of the grooves is 20 μm or more and 300 μm or less, a depth D of the grooves is 10 μm or more and 40 μm or less, and a pitch P of the grooves in the rolling direction is 1.0 mm or more and 30.0 mm or less, and
at an inside of the glass coating at surfaces of recessed parts of the grooves, one or more fine grains of a long axis of 1 μm or more and 20 μm or less are present in a cross-section perpendicular to the longitudinal direction of the grooves.

### Claim 2 (depends on 1)

The grain-oriented electrical steel sheet according to claim 1, wherein the crystal orientation of the fine grains differs by 5° or more from a Goss orientation of the crystal orientation of the adjacent base material steel sheet.

### Claim 3 (depends on 1)

A method of production of the grain-oriented electrical steel sheet according to claim 1, which method of production of the grain-oriented electrical steel sheet includes a groove forming step of lasering the surface of the steel sheet to form grooves and, as a condition for lasering, a focused spot diameter dL of the laser in the rolling direction and a focused spot diameter dC in the sheet width direction satisfy formula (1):
0.01
≤
dL
/
dC
≤
1.
.
formula
⁢
(
1
)

### Claim 4 (depends on 2)

A method of production of the grain-oriented electrical steel sheet according to claim 2, which method of production of the grain-oriented electrical steel sheet includes a groove forming step of lasering the surface of the steel sheet to form grooves and, as a condition for lasering, a focused spot diameter dL of the laser in the rolling direction and a focused spot diameter dC in the sheet width direction satisfy formula (1):
0.01
≤
dL
/
dC
≤
1.
.
formula
⁢
(
1
)