公开(公告)号：US20220020514A1

公开(公告)日：2022-01-20

申请号：US17298672

申请日：2019-11-21

Applicant: JFE STEEL CORPORATION

Inventor： Takeshi OMURA ,  Yoshihisa ICHIHARA ,  Kunihiro SENDA ,  Takahiro KOSHIHARA

IPC: H01F1/147 ,  C21D9/46 ,  C21D6/00 ,  C21D1/34 ,  C22C38/34 ,  C22C38/60 ,  C22C38/22 ,  C22C38/06 ,  C22C38/04 ,  C22C38/00

Abstract: Disclosed is a grain-oriented electrical steel sheet with extremely low iron loss by means of a magnetic domain refining technique. In a grain-oriented electrical steel sheet having a plurality of magnetic domains refined via a local strain introduction portion, when a direct-current external magnetic field is applied to the steel sheet in a rolling direction, for a magnetic flux leaked from the local strain introduction portion at a position 1.0 mm away from a surface of the steel sheet at a side of the local strain introduction portion, a value obtained by dividing an intensity level of a total leakage magnetic flux by an intensity level of a magnetic flux leaked due to causes other than strain is more than 1.2.

公开(公告)号：US20250154618A1

公开(公告)日：2025-05-15

申请号：US19020031

申请日：2025-01-14

Applicant: JFE STEEL CORPORATION

Inventor： Hirotaka INOUE ,  Takeshi OMURA ,  Yoshihisa ICHIHARA ,  Shigehiro TAKAJO ,  Kunihiro SENDA

IPC: C21D9/46 ,  C21D6/00 ,  C21D8/12 ,  H01F1/16

Abstract: A method of manufacturing a grain-oriented electrical steel sheet includes sequentially subjecting a slab for grain-oriented electrical steel sheet to hot rolling, cold rolling, decarburization annealing, final annealing after applying an annealing separator to a surface of the steel sheet, and flattening annealing. After the cold rolling and before the applying of an annealing separator, resist ink is applied to one side of the steel sheet. A laser is repeatedly scanned across a rolling direction of the steel sheet on the applied surface to remove resist ink. Electrolytic etching is applied on the removed areas to form grooves that extend linearly across the rolling direction and are lined up at intervals in the rolling direction. The scanning of the laser is performed with an irradiation energy of the laser being less than 30 J/m and a temperature of the steel sheet being 40° C. to 200° C.

公开(公告)号：US20240209483A1

公开(公告)日：2024-06-27

申请号：US18562530

申请日：2022-05-24

Applicant: JFE STEEL CORPORATION

Inventor： Yoshihisa ICHIHARA ,  Takeshi OMURA ,  Kunihiro SENDA

IPC: C22C38/02 ,  C21D8/12 ,  C22C38/04

CPC classification number: C22C38/02 ,  C21D8/1294 ,  C22C38/04 ,  C21D2201/05

Abstract: Disclosed is a grain-oriented electrical steel sheet that exhibits excellent transformer characteristics and that has low iron loss and low magnetostriction properties. The grain-oriented electrical steel sheet has a magnetic flux density B-magnetostriction waveform λ, referred to as a butterfly curve, when excited to 1.5 T or more, such that an amount of steel sheet elongation (Δλ) with a magnetic flux density B ranging from 1.0 T to 1.5 T is 0.010×10−6 or more and 0.240×10−6 or less, and a length of a closure domain in the rolling direction, referred to as a closure domain width, is 20 μm or more and 240 μm or less.

公开(公告)号：US20240011111A1

公开(公告)日：2024-01-11

申请号：US18253922

申请日：2021-09-29

Applicant: JFE STEEL CORPORATION

Inventor： Takeshi OMURA ,  Yoshihisa ICHIHARA ,  Kunihiro SENDA

IPC: C21D8/12 ,  C22C38/02 ,  C22C38/04 ,  C21D10/00

CPC classification number: C21D8/1222 ,  C22C38/02 ,  C22C38/04 ,  C21D8/1233 ,  C21D8/1255 ,  C21D10/005 ,  C21D2201/05

Abstract: Provided is a grain-oriented electrical steel sheet comprising a magnetic flux density B8 of 1.92 T or more, wherein a ratio Wa/Wb of a film thickness Wa of a forsterite film on a strain-introduced surface to a film thickness Wb of a forsterite film on a non-strain-introduced surface is 0.5 or more, an average width of a magnetic domain discontinuous portion on the non-strain-introduced surface is 1.00 time or more of an average width of a magnetic domain discontinuous portion on the strain-introduced surface, the average width of the magnetic domain discontinuous portion on the non-strain-introduced surface is 400 μm or less, and compressive stress exists in a rolling direction in a range from a surface of the steel sheet that is the strain-introduced surface to at least 2 μm in a sheet thickness direction.

公开(公告)号：US20230304123A1

公开(公告)日：2023-09-28

申请号：US18041798

申请日：2021-08-18

Applicant: JFE STEEL CORPORATION

Inventor： Kunihiro SENDA ,  Yoshihisa ICHIHARA ,  Takeshi OMURA

IPC: C21D10/00

CPC classification number: C21D10/005 ,  C21D2201/05 ,  C21D2221/00

Abstract: To provide a grain-oriented electrical steel sheet that can achieve both sufficiently low transformer core loss and sufficiently low noise. Disclosed is a grain-oriented electrical steel sheet having a tension coating on a surface thereof and subjected to magnetic domain refining treatment by generating linear closure domains extending in a direction within 30° of a transverse direction, in which an average interval L between adjacent closure domains is 15 mm or less, a depth ratio rd of a depth of the closure domains to a sheet thickness, calculated by a predetermined formula, is 35% or more, and a volume fraction rv of the closure domains, calculated by a predetermined formula, is 0.30% or more and 3.0% or less, and an area ratio rs of the closure domains, calculated by a predetermined formula, is 0.50% or more and 4.0% or less.

公开(公告)号：US20230212706A1

公开(公告)日：2023-07-06

申请号：US17998926

申请日：2021-03-26

Applicant: JFE STEEL CORPORATION

Inventor： Hirotaka INOUE ,  Takeshi OMURA ,  Yoshihisa ICHIHARA ,  Shigehiro TAKAJO ,  Kunihiro SENDA

IPC: C21D9/46 ,  C21D8/12 ,  C21D6/00 ,  H01F1/16

CPC classification number: C21D9/46 ,  C21D8/1255 ,  C21D8/1283 ,  C21D8/1222 ,  C21D8/1233 ,  C21D6/008 ,  C21D8/1294 ,  C21D8/1272 ,  H01F1/16

Abstract: Provided is a grain-oriented electrical steel sheet which has been subjected to heat-resistant magnetic domain refining treatment and can effectively suppress carburizing and nitriding during stress relief annealing. The grain-oriented electrical steel sheet has a plurality of grooves on one side that extend linearly across the rolling direction and are lined up at intervals in the rolling direction, and has at least a forsterite film on a surface of the steel sheet, where an average thickness of the forsterite film formed on the floor of the grooves is 0.45 μm or more, and a standard deviation a of the thickness is 0.34 μm or less.

公开(公告)号：US20230212703A1

公开(公告)日：2023-07-06

申请号：US17997044

申请日：2021-03-26

Applicant: JFE STEEL CORPORATION

Inventor： Ryuichi SUEHIRO ,  Takeshi OMURA ,  Shigehiro TAKAJO ,  Yoshihisa ICHIHARA

IPC: C21D8/12 ,  C21D9/46 ,  C22C38/60 ,  C22C38/02 ,  C22C38/04 ,  C22C38/06 ,  C22C38/00 ,  B23K26/364 ,  B23K26/402 ,  H01F1/16

CPC classification number: C21D8/1277 ,  C21D9/46 ,  C21D8/1222 ,  C21D8/1233 ,  C21D8/1261 ,  C21D8/1272 ,  C22C38/60 ,  C22C38/02 ,  C22C38/04 ,  C22C38/06 ,  C22C38/001 ,  C22C38/002 ,  B23K26/364 ,  B23K26/402 ,  H01F1/16 ,  C22C2202/02

Abstract: To form linear grooves of desired groove width on a metal strip surface and provide a grain-oriented electrical steel sheet having excellent magnetic properties, a linear groove formation method comprises: forming a resist coating on at least one surface of a metal strip; thereafter irradiating the resist coating with a laser while scanning the laser in a direction crossing a rolling direction of the metal strip, to remove the resist coating in a part irradiated with the laser; and thereafter performing etching treatment to form a linear groove in a part of the metal strip in which the resist coating is removed, wherein the resist coating contains a predetermined amount of an inorganic compound, and on the surface of the metal strip, the laser has a predetermined elliptic beam shape.

公开(公告)号：US20220267872A1

公开(公告)日：2022-08-25

申请号：US17630853

申请日：2020-07-03

Applicant: JFE STEEL CORPORATION

Inventor： Yoshihisa ICHIHARA ,  Takeshi OMURA ,  Hirotaka INOUE ,  Shigehiro TAKAJO

IPC: C21D8/12

Abstract: A linear groove formation method including forming a coated resist on a surface of a steel sheet, irradiating two or more laser beams onto the surface of the steel sheet while scanning the laser beams in a direction intersecting the rolling direction of the steel sheet cyclically in a rolling direction of the steel sheet, and forming linear grooves by etching portions of the steel sheet. In the laser irradiating process, the coated resist is removed continuously in a sheet transverse direction of the steel sheet by using the laser beams irradiated from respective ones of two or more laser irradiation devices arranged in the sheet transverse direction, and the laser beams are irradiated by shifting centers of two of the laser beams irradiated from two of the laser two of the laser irradiation devices adjacent to each other in the sheet transverse direction.