公开(公告)号：US20250075300A1

公开(公告)日：2025-03-06

申请号：US18726019

申请日：2022-12-21

Applicant: JFE STEEL CORPORATION

Inventor： Hiroi YAMAGUCHI ,  Takeshi IMAMURA ,  Yoshihisa ICHIHARA ,  Takeshi OMURA

IPC: C22C38/02 ,  C22C38/00 ,  C22C38/04

Abstract: The present disclosure proposes a grain-oriented electrical steel sheet that reduces iron loss by controlling the magnetic domain structure and can maintain the iron loss reduction effect even after subjection to stress relief annealing. The grain-oriented electrical steel sheet comprising a predetermined chemical composition and a local area having a misorientation angle of 1.5 degrees or more from surrounding crystals and extending linearly in a direction crossing a rolling direction on at least one of front and back surfaces of the steel sheet, wherein the local area has a volume fraction of 0.1% or more and 2.0% or less and a residual stress of 100 MPa or less, and the surface having the local area has an average amount of roughness on a steel substrate being less than 5 μm.

公开(公告)号：US20240368717A1

公开(公告)日：2024-11-07

申请号：US18561053

申请日：2022-05-27

Applicant: JFE STEEL CORPORATION

Inventor： Takeshi IMAMURA ,  Masanori TAKENAKA ,  Eitaro SHIDARA

IPC: C21D1/26 ,  C21D1/60 ,  C21D1/76 ,  C21D8/02

Abstract: The present disclosure is to reduce the number of surface defects in a grain-oriented electrical steel sheet. When manufacturing a grain-oriented electrical steel sheet, a steel slab is heated before being subjected to hot rolling. The heating includes a first heating process of heating the steel slab to a temperature of lower than 1300° C., and a second heating process of heating the steel slab to a temperature of 1300° C. or higher, where the time from the end of the first heating process to the start of the second heating process is 20 seconds or longer, the oxygen concentration in the atmosphere in the second heating process is 1.0 vol % or less, and the surface of the steel slab is subjected to water cooling at a cooling rate of 3.0° C./s or higher after the second heating process and before the hot rolling.

公开(公告)号：US20240263285A1

公开(公告)日：2024-08-08

申请号：US18561389

申请日：2022-05-27

Applicant: JFE STEEL CORPORATION

Inventor： Takeshi IMAMURA ,  Masanori TAKENAKA ,  Takafumi SUZUKI

IPC: C22C38/02 ,  C21D6/00 ,  C21D8/12 ,  C21D9/46 ,  C22C38/04

CPC classification number: C22C38/02 ,  C21D6/008 ,  C21D8/1222 ,  C21D8/1233 ,  C21D8/1255 ,  C21D8/1266 ,  C21D8/1272 ,  C21D8/1283 ,  C21D9/46 ,  C22C38/04

Abstract: Provided is a method of manufacturing a grain-oriented electrical steel sheet having an excellent film adhesion can be obtained. The method of manufacturing a grain-oriented electrical steel sheet includes subjecting a steel slab to hot rolling to obtain a hot-rolled steel sheet, subjecting the hot-rolled steel sheet to cold rolling once to obtain a cold-rolled steel sheet, subjecting the cold-rolled steel sheet to pickling, subjecting the cold-rolled steel sheet to decarburization annealing, applying an annealing separator to a surface of the cold-rolled steel sheet after the decarburization annealing, and subjecting the cold-rolled steel sheet to final annealing, where in the pickling, a solution with an acid concentration of 1.0 mass % to 20 mass % and an Fe ion concentration of 2 mass % to 15 mass % is used, and in the decarburization annealing, a concentration of CO in an atmosphere gas is maintained at 6 vol % or less.

公开(公告)号：US20220098697A1

公开(公告)日：2022-03-31

申请号：US17426729

申请日：2020-01-30

Applicant: JFE STEEL CORPORATION

Inventor： Takeshi IMAMURA ,  Makoto WATANABE

IPC: C21D9/46 ,  C22C38/00 ,  C22C38/02 ,  C22C38/04 ,  C22C38/12 ,  C22C38/42 ,  C22C38/48 ,  C22C38/60 ,  C21D8/12

Abstract: Provided are a grain-oriented electrical steel sheet having excellent iron loss property without using magnetic domain refining treatment and an iron core produced using the same. The steel sheet comprises: a predetermined chemical composition; and a steel microstructure in which: crystal grains are made up of coarse secondary recrystallized grains of 5.0 mm or more, fine grains of more than 2.0 mm and less than 5.0 mm contained at a frequency of 0.2 to 5 grains per cm2, and very fine grains of 2.0 mm or less; for each coarse secondary recrystallized grain extending through the sheet in a thickness direction, an area ratio of a region in which projected surfaces of exposed areas of the coarse secondary recrystallized grain on a front side and a back side of the sheet coincide with each other to each of the exposed areas is 95% or more.

公开(公告)号：US20240249863A1

公开(公告)日：2024-07-25

申请号：US18561412

申请日：2022-05-27

Applicant: JFE STEEL CORPORATION

Inventor： Takeshi IMAMURA ,  Yukihiro SHINGAKI ,  Masanori TAKENAKA ,  Takashi TERASHIMA

IPC: H01F1/147 ,  C21D1/74 ,  C21D6/00 ,  C21D8/12 ,  C21D9/46 ,  C22C38/00 ,  C22C38/02 ,  C22C38/04 ,  C22C38/06 ,  C22C38/08 ,  C22C38/10 ,  C22C38/12 ,  C22C38/14 ,  C22C38/16 ,  C22C38/20 ,  C22C38/24 ,  C22C38/26 ,  C22C38/28 ,  C22C38/34 ,  C22C38/60

CPC classification number: H01F1/14791 ,  C21D1/74 ,  C21D6/001 ,  C21D6/002 ,  C21D6/005 ,  C21D6/007 ,  C21D6/008 ,  C21D8/1222 ,  C21D8/1233 ,  C21D8/1255 ,  C21D8/1261 ,  C21D8/1266 ,  C21D8/1283 ,  C21D9/46 ,  C22C38/001 ,  C22C38/002 ,  C22C38/008 ,  C22C38/02 ,  C22C38/04 ,  C22C38/06 ,  C22C38/08 ,  C22C38/10 ,  C22C38/12 ,  C22C38/14 ,  C22C38/16 ,  C22C38/20 ,  C22C38/24 ,  C22C38/26 ,  C22C38/28 ,  C22C38/34 ,  C22C38/60 ,  C22C2202/02

Abstract: To provide a grain-oriented electrical steel sheet with good processing accuracy in rounding while maintaining excellent magnetic properties, and a producing method thereof. Disclosed is the method including: subjecting a steel material to heating to 1300° C. or higher and hot rolling, subjecting the resulting sheet directly, or after subjection to hot-rolled sheet annealing, to at least two cycles of cold rolling with intermediate annealing therebetween, decarburization annealing, application of an annealing separator to a surface of the sheet, final annealing, in which maximum arrival temperatures in the first and second cycles of the cold rolling satisfy a predetermined relation, total rolling reductions in the first and second cycles of the cold rolling satisfy a predetermined relation, and in the final annealing, an average heating rates in temperature ranges from 50° C. to 1000° C. and from 1000° C. to (maximum arrival temperature—50° C.) satisfy a predetermined relation.

公开(公告)号：US20230307160A1

公开(公告)日：2023-09-28

申请号：US18040813

申请日：2021-08-26

Applicant: JFE STEEL CORPORATION

Inventor： Hiroi YAMAGUCHI ,  Takeshi IMAMURA ,  Takeshi OMURA ,  Yoshihisa ICHIHARA

IPC: H01F1/147 ,  C21D8/12 ,  C21D6/00 ,  C22C38/60 ,  C22C38/12 ,  C22C38/06 ,  C22C38/02 ,  C22C38/00 ,  C22C38/04

CPC classification number: H01F1/147 ,  C21D8/1244 ,  C21D6/008 ,  C22C38/60 ,  C22C38/12 ,  C22C38/06 ,  C22C38/02 ,  C22C38/002 ,  C22C38/04 ,  C22C38/001 ,  C22C2202/02

Abstract: Provided is a method for manufacturing a grain-oriented electrical steel sheet to reduce iron loss by controlling the magnetic domain structure, in which the iron loss reduction effect can be maintained even when stress relief annealing is applied, and the magnetic flux density does not decrease after the magnetic domain control treatment. In the manufacturing method, on a surface of the grain oriented electrical steel sheet, a laser beam with a ring-shaped intensity distribution in which the intensity in a periphery is lower than that in a center is irradiated in a linear manner in a direction intersecting a rolling direction of the steel sheet.

公开(公告)号：US20190112685A1

公开(公告)日：2019-04-18

申请号：US15774370

申请日：2016-11-30

Applicant: JFE STEEL CORPORATION

Inventor： Masanori TAKENAKA ,  Yasuyuki HAYAKAWA ,  Takeshi IMAMURA ,  Yuiko EHASHI

IPC: C21D8/12 ,  C21D6/00 ,  H01F1/147 ,  C22C38/00 ,  C22C38/02 ,  C22C38/04 ,  C22C38/06 ,  C22C38/60

Abstract: A grain-oriented electrical steel sheet has magnetic properties improved over conventional grain-oriented electrical steel sheets. A method of producing a grain-oriented electrical steel sheet comprises: heating a steel slab at 1300° C. or less, the steel slab having a chemical composition containing C, Si, Mn, acid-soluble Al, S and/or Se, Sn and/or Sb, N, and a balance being Fe and inevitable impurities; subjecting the steel slab to hot rolling to obtain a hot rolled steel sheet; subjecting the hot rolled steel sheet to cold rolling once, or twice or more with intermediate annealing performed therebetween, to obtain a cold rolled steel sheet with a final sheet thickness; subjecting the cold rolled steel sheet to primary recrystallization annealing; applying an annealing separator to a surface of the cold rolled steel sheet after the primary recrystallization annealing; and then subjecting the cold rolled steel sheet to secondary recrystallization annealing.

公开(公告)号：US20240240293A1

公开(公告)日：2024-07-18

申请号：US18561841

申请日：2022-05-27

Applicant: JFE STEEL CORPORATION

Inventor： Takeshi IMAMURA ,  Ayaka YOSHIKAWA ,  Masanori TAKENAKA ,  Hiroi YAMAGUCHI

IPC: C22C38/02 ,  C21D1/26 ,  C21D3/04 ,  C21D6/00 ,  C21D8/00 ,  C21D8/12 ,  C22C38/04 ,  C23G1/08

CPC classification number: C22C38/02 ,  C21D1/26 ,  C21D3/04 ,  C21D6/008 ,  C21D8/005 ,  C21D8/1222 ,  C21D8/1233 ,  C21D8/1255 ,  C21D8/1272 ,  C21D8/1283 ,  C22C38/04 ,  C23G1/08 ,  C21D2201/05

Abstract: To provide a method for producing a grain-oriented electrical steel sheet that can solve the problem of cracking in steel sheets during final cold rolling and that can stably produce a grain-oriented electrical steel sheet with low iron loss. A production method includes predetermined steps, wherein the conditions: T≤−4000×A+440, and T≤360 are satisfied, where A denotes an average C content in mass % in a predetermined region of the steel sheet after subjection to annealing preceding final cold rolling and before subjection to the final cold rolling, and T denotes a time in hours from just after the completion of the annealing preceding the final cold rolling to just before the start of the final cold rolling, and after the final cold rolling and before the decarburization annealing, pickling treatment is performed with a predetermined treatment solution.

公开(公告)号：US20200040419A1

公开(公告)日：2020-02-06

申请号：US16483860

申请日：2018-02-19

Applicant: JFE STEEL CORPORATION

Inventor： Masanori TAKENAKA ,  Takeshi IMAMURA ,  Yuiko EHASHI ,  Hiroi YAMAGUCHI

IPC: C21D9/46 ,  C22C38/54 ,  C22C38/34 ,  C22C38/22 ,  C22C38/20 ,  C22C38/06 ,  C22C38/04 ,  C22C38/00 ,  C21D8/12 ,  C21D8/00 ,  C21D6/00 ,  H01F1/147

Abstract: In a grain-oriented electrical steel sheet which is manufactured from a thin slab without using an inhibitor forming component, excellent magnetic properties are stably achieved. In a method for manufacturing a grain-oriented electrical steel sheet, a slab heating and annealing are performed under specific conditions.

公开(公告)号：US20190271054A1

公开(公告)日：2019-09-05

申请号：US16078010

申请日：2017-03-09

Applicant: JFE STEEL CORPORATION

Inventor： Yuiko EHASHI ,  Masanori TAKENAKA ,  Yasuyuki HAYAKAWA ,  Minoru TAKASHIMA ,  Takeshi IMAMURA

IPC: C21D9/46 ,  C21D8/12 ,  C21D6/00 ,  C22C38/60 ,  C22C38/18 ,  C22C38/12 ,  C22C38/16 ,  C22C38/40 ,  C22C38/14 ,  C22C38/08 ,  C22C38/06 ,  C22C38/04 ,  C22C38/02 ,  C22C38/00

Abstract: To provide a grain-oriented electrical steel sheet that has better magnetic property than conventional ones without requiring high-temperature slab heating, in the case of not performing intermediate annealing, the hot rolled steel sheet obtained by a predetermined step is subjected to hot band annealing, and, in a heating process in the hot band annealing, heating is performed at a heating rate of 10° C./s or less for 10 sec or more and 120 sec or less in a temperature range of 700° C. or more and 950° C. or less, and in the case of performing the intermediate annealing, in a heating process in final intermediate annealing, heating is performed at a heating rate of 10° C./s or less for 10 sec or more and 120 sec or less in a temperature range of 700° C. or more and 950° C. or less.