公开(公告)号：US20230220510A1

公开(公告)日：2023-07-13

申请号：US18010871

申请日：2021-06-30

Applicant: JFE STEEL CORPORATION

Inventor： Shinsuke KOMINE ,  Tatsuya NAKAGAITO ,  Kentaro SATO ,  Tomohiro SAKAIDANI

IPC: C21D9/46 ,  C22C38/00 ,  C22C38/02 ,  C22C38/04 ,  C22C38/06 ,  C22C38/60 ,  C21D8/02 ,  C23C2/06 ,  C23C2/40 ,  C25D3/22

CPC classification number: C21D9/46 ,  C22C38/001 ,  C22C38/002 ,  C22C38/02 ,  C22C38/04 ,  C22C38/06 ,  C22C38/60 ,  C21D8/0226 ,  C21D8/0236 ,  C21D8/0273 ,  C23C2/06 ,  C23C2/40 ,  C25D3/22 ,  C21D2211/005 ,  C21D2211/002 ,  C21D2211/008 ,  C21D2211/001

Abstract: A steel sheet including a chemical composition satisfying an equivalent carbon content of 0.60% or more and less than 0.85%, and a steel microstructure with an area fraction of ferrite: less than 40%, tempered martensite and bainite: 40% or more in total, retained austenite: 3% to 15%, and ferrite, tempered martensite, bainite, and retained austenite: 93% or more in total. A 90-degree bending at a curvature radius/thickness ratio of 4.2 in a rolling (L) direction with respect to an axis extending in a width (C) direction causes a change of 0.40 or more in (a grain size in a thickness direction)/(a grain size in a direction perpendicular to the thickness) of the tempered martensite in an L cross section in a 0- to 50-μm region from a surface of the steel sheet on a compression side. The steel sheet has a tensile strength of 980 MPa or more.

公开(公告)号：US20230235421A1

公开(公告)日：2023-07-27

申请号：US18247073

申请日：2021-08-05

Applicant: JFE STEEL CORPORATION

Inventor： Yuji TANAKA ,  Masaki TADA ,  Yuki TOJI ,  Shinsuke KOMINE ,  Yoshie OBATA ,  Yusuke KIMATA

IPC: C21D8/02 ,  C21D9/46 ,  C22C38/00 ,  C22C38/02 ,  C22C38/04 ,  C22C38/06 ,  C22C38/12 ,  C22C38/14 ,  C23C2/20

CPC classification number: C21D8/0268 ,  C21D9/46 ,  C22C38/001 ,  C22C38/002 ,  C22C38/02 ,  C22C38/04 ,  C22C38/06 ,  C22C38/12 ,  C22C38/14 ,  C21D8/0226 ,  C21D8/0263 ,  C23C2/20 ,  C21D2211/001 ,  C21D2211/002 ,  C21D2211/005 ,  C21D2211/008

Abstract: A high-strength cold-rolled steel sheet comprises: a chemical composition that contains C, Si, Mn, P, S, N, Al, Ti, Nb, and B with a balance consisting of Fe and inevitable impurities, and satisfies [mol % N]/[mol % Ti]

公开(公告)号：US20230243014A1

公开(公告)日：2023-08-03

申请号：US18011090

申请日：2021-06-30

Applicant: JFE STEEL CORPORATION

Inventor： Shinsuke KOMINE ,  Tatsuya NAKAGAITO ,  Kentaro SATO ,  Tomohiro SAKAIDANI

IPC: C21D9/46 ,  C22C33/04 ,  C22C38/60 ,  C22C38/28 ,  C22C38/32 ,  C22C38/38 ,  C22C38/34 ,  C22C38/16 ,  C22C38/14 ,  C22C38/12 ,  C22C38/08 ,  C22C38/06 ,  C22C38/04 ,  C22C38/02 ,  C22C38/00 ,  C21D8/02 ,  C21D6/00 ,  C21D1/18 ,  C25D3/22 ,  C25D5/36 ,  C25D5/50 ,  C23C2/28 ,  C23C2/40

CPC classification number: C21D9/46 ,  C22C33/04 ,  C22C38/60 ,  C22C38/28 ,  C22C38/32 ,  C22C38/38 ,  C22C38/34 ,  C22C38/16 ,  C22C38/14 ,  C22C38/12 ,  C22C38/08 ,  C22C38/06 ,  C22C38/04 ,  C22C38/02 ,  C22C38/008 ,  C22C38/005 ,  C22C38/002 ,  C22C38/001 ,  C21D8/0205 ,  C21D8/0226 ,  C21D8/0236 ,  C21D8/0263 ,  C21D8/0278 ,  C21D6/001 ,  C21D6/002 ,  C21D6/005 ,  C21D6/008 ,  C21D1/18 ,  C25D3/22 ,  C25D5/36 ,  C25D5/50 ,  C23C2/29 ,  C23C2/40 ,  C21D2211/005 ,  C21D2211/008 ,  C21D2211/002 ,  C21D2211/001

Abstract: A galvanized steel sheet includes: a steel sheet having a chemical composition satisfying an equivalent carbon content Ceq of 0.35% or more and less than 0.60%, and a specified steel microstructure; and a galvanized layer on a surface of the steel sheet. The retained austenite has a solute C content of 0.6% or more by mass, and retained austenite grains with an aspect ratio of less than 2.0 constitute 50% or more of all retained austenite grains. In 90-degree bending at a curvature radius/thickness ratio of 4.2 in a rolling (L) direction with respect to an axis extending in a width (C) direction, an L cross section in a 0 to 50 μm region from a surface of the steel sheet on a compression side has a number density of voids of 1000/mm2 or less, and the galvanized steel sheet has a tensile strength of 590 MPa or more.

公开(公告)号：US20210040577A1

公开(公告)日：2021-02-11

申请号：US16966762

申请日：2019-01-21

Applicant: JFE STEEL CORPORATION

Inventor： Seigo TSUCHIHASHI ,  Shinsuke KOMINE ,  Tatsuya NAKAGAITO ,  Hidekazu MINAMI

IPC: C21D9/46 ,  C21D8/02 ,  C23C2/06 ,  C22C38/00 ,  C22C38/02 ,  C22C38/04 ,  C22C38/06 ,  C22C38/10 ,  C22C38/12 ,  C22C38/14 ,  C22C38/20 ,  C22C38/32 ,  C22C38/60

Abstract: A high-strength cold-rolled steel sheet or high-strength coated steel sheet that has a tensile strength (TS) of 780 MPa or more and has high ductility, stretch-flangeability, and in-plane stability of stretch-flangeability and methods for producing the same. The high-strength cold-rolled steel sheet has a specified chemical composition and a microstructure comprising, by area fraction, in a range of 50% to 80% of ferrite, 8% or less of martensite with an average grain size of 2.5 μm or less, in a range of 6% to 15% of retained austenite, and in a range of 3% to 40% of tempered martensite. A ratio fM/fM+TM being 50% or less, where fM denotes the area fraction of martensite and fM+TM denotes the total area fraction of martensite and tempered martensite, and a standard deviation of the grain size of martensite at certain portions being 0.7 μm or less.

公开(公告)号：US20250163531A1

公开(公告)日：2025-05-22

申请号：US18839776

申请日：2022-11-29

Applicant: JFE Steel Corporation

Inventor： Shinsuke KOMINE ,  Tatsuya NAKAGAITO

IPC: C21D9/46 ,  C21D1/18 ,  C21D8/02 ,  C22C38/00 ,  C22C38/02 ,  C22C38/04 ,  C22C38/06 ,  C23C2/06

Abstract: A steel sheet, a member, and methods for manufacturing both are disclosed.
A steel sheet has a chemical composition satisfying a carbon equivalent of 0.18% or more and less than 0.46% and a specific steel microstructure. In the steel sheet, an average crystal grain size of ferrite is 25 μm or less, coefficient of variation of ferrite grain size×carbon equivalent is 0.25 or less, when the steel sheet is bent by 90° in a rolling direction with a width direction as an axis at radius of curvature/sheet thickness: 4.2 and then unbent, the ratio of ferrite grains having a void at an interface to all ferrite grains is 5% or less in an L section in a region extending by 0 to 50 μm from a steel sheet surface on a compressive-tensile deformation side, and a tensile strength is 440 MPa or more and less than 780 MPa.

公开(公告)号：US20240158885A1

公开(公告)日：2024-05-16

申请号：US18549589

申请日：2022-02-14

Applicant: JFE STEEL CORPORATION

Inventor： Kenichi OSUKA ,  Maiko WATANABE ,  Shinsuke KOMINE ,  Hideyuki TAKAHASHI

IPC: C21D11/00 ,  C21D8/02 ,  C21D9/60 ,  C23C2/00

CPC classification number: C21D11/00 ,  C21D8/0205 ,  C21D8/0226 ,  C21D8/0236 ,  C21D8/0263 ,  C21D8/0278 ,  C21D9/60 ,  C23C2/004 ,  C21D2211/001

Abstract: To provide continuous annealing equipment, a continuous annealing method, a method of producing cold-rolled steel sheets and a method of producing coated or plated steel sheets which enable a quick response to fluctuations in material properties and enable minimization of fluctuations in mechanical properties of products. The continuous annealing equipment is continuous annealing equipment for steel sheets including, in this order, a heating zone (6) and a soaking zone (7), the soaking zone (7) including a first soaking zone (7A) and a second soaking zone (7B) provided after the first soaking zone (7A), the continuous annealing equipment including: a first induction heating device (9) provided between first soaking zone (7A) and a second soaking zone (7B); and a measuring device (10) configured to measure austenite fractions of the steel sheets at an exit of the second soaking zone (7B).

公开(公告)号：US20220018747A1

公开(公告)日：2022-01-20

申请号：US17311236

申请日：2019-12-16

Applicant: JFE STEEL CORPORATION

Inventor： Kentaro SATO ,  Takayuki FUTATSUKA ,  Tomohiro SAKAIDANI ,  Shinsuke KOMINE ,  Yoshiyasu KAWASAKI

IPC: G01N3/20 ,  G01N3/24 ,  G01N3/307

Abstract: A collision performance evaluation test with few variations in test results with high accuracy in which a complicated phenomenon that actually occurs can be reproduced in a simple manner by considering the history of deformation in both the press forming and a collision. A collision performance evaluation test method for a metal sheet material for an automobile body is characterized in that a press working apparatus first forms a flat test specimen made of a metal sheet material to be tested into a V shape by primary bending, a bending test apparatus then deforms, by secondary bending, the test specimen formed by the primary bending in a direction intersecting with the primary bending direction, and a bending load and a bending stroke for the test specimen during the secondary bending deformation are recorded and evaluated.

公开(公告)号：US20240229201A1

公开(公告)日：2024-07-11

申请号：US18010928

申请日：2021-06-30

Applicant: JFE STEEL CORPORATION

Inventor： Shinsuke KOMINE ,  Tatsuya NAKAGAITO ,  Kentaro SATO ,  Tomohiro SAKAIDANI

IPC: C22C38/04 ,  C21D1/22 ,  C21D8/02 ,  C22C38/02 ,  C22C38/06 ,  C23C2/06

CPC classification number: C22C38/04 ,  C21D1/22 ,  C21D8/0205 ,  C21D8/0226 ,  C21D8/0236 ,  C21D8/0273 ,  C22C38/02 ,  C22C38/06 ,  C23C2/06 ,  C21D2211/001 ,  C21D2211/002 ,  C21D2211/005 ,  C21D2211/008

Abstract: A steel sheet including a chemical composition satisfying an equivalent carbon content of 0.35% or more and less than 0.60% and a steel microstructure with an area fraction of ferrite: 40% to 85%, tempered martensite and bainite: 10% to 55% in total, retained austenite: 3% to 15%, and ferrite, tempered martensite, bainite, and retained austenite: 93% or more in total. A 90-degree bending at a curvature radius/thickness ratio of 4.2 in a rolling (L) direction with respect to an axis extending in a width (C) direction causes a change of 0.50 or more in (a grain size in a thickness direction)/(a grain size in a direction perpendicular to the thickness) of the tempered martensite in an L cross section in a 0- to 50-μm region from a surface of the steel sheet on a compression side, and the steel sheet has a tensile strength of 590 MPa or more.

公开(公告)号：US20230374622A1

公开(公告)日：2023-11-23

申请号：US18247071

申请日：2021-08-05

Applicant: JFE STEEL CORPORATION

Inventor： Yuji TANAKA ,  Masaki TADA ,  Yuki TOJI ,  Shinsuke KOMINE ,  Yoshie OBATA ,  Yusuke KIMATA

IPC: C21D9/46 ,  C22C38/60 ,  C22C38/38 ,  C22C38/34 ,  C22C38/32 ,  C22C38/28 ,  C22C38/26 ,  C22C38/16 ,  C22C38/14 ,  C22C38/12 ,  C22C38/10 ,  C22C38/08 ,  C22C38/06 ,  C22C38/04 ,  C22C38/02 ,  C22C38/00 ,  C21D8/02 ,  C21D1/18 ,  C21D6/00

CPC classification number: C21D9/46 ,  C22C38/60 ,  C22C38/38 ,  C22C38/34 ,  C22C38/32 ,  C22C38/28 ,  C22C38/26 ,  C22C38/16 ,  C22C38/14 ,  C22C38/12 ,  C22C38/10 ,  C22C38/08 ,  C22C38/06 ,  C22C38/04 ,  C22C38/02 ,  C22C38/002 ,  C22C38/001 ,  C22C38/005 ,  C21D8/0205 ,  C21D8/0226 ,  C21D8/0236 ,  C21D8/0263 ,  C21D1/18 ,  C21D6/001 ,  C21D6/002 ,  C21D6/005 ,  C21D6/007 ,  C21D6/008 ,  C21D2211/005 ,  C21D2211/008 ,  C21D2211/002 ,  C21D2211/001

Abstract: A high-strength cold-rolled steel sheet comprises: a chemical composition that contains C, Si, Mn, P, S, N, Al, Ti, Nb, and B with a balance consisting of Fe and inevitable impurities, and satisfies [mol % N]/[mol % Ti]

公开(公告)号：US20230287553A1

公开(公告)日：2023-09-14

申请号：US18010998

申请日：2021-06-30

Applicant: JFE STEEL CORPORATION

Inventor： Shinsuke KOMINE ,  Tatsuya NAKAGAITO ,  Kentaro SATO ,  Tomohiro SAKAIDANI

IPC: C23C2/06 ,  C22C38/02 ,  C22C38/04 ,  C22C38/60 ,  C22C38/06 ,  C22C38/00 ,  C23C2/28 ,  C21D9/46

CPC classification number: C23C2/06 ,  C21D9/46 ,  C22C38/001 ,  C22C38/02 ,  C22C38/04 ,  C22C38/06 ,  C22C38/60 ,  C23C2/29 ,  C21D2211/001 ,  C21D2211/002 ,  C21D2211/008

Abstract: A galvanized steel sheet including a steel sheet having a chemical composition with an equivalent carbon content Ceq of 0.60% or more and less than 0.85%, and a specified steel microstructure; and a galvanized layer on a surface of the steel sheet. The retained austenite has a solute C content of 0.6% or more by mass, and retained austenite grains with an aspect ratio of less than 2.0 constitute 50% or more of all retained austenite grains. In 90-degree bending at a curvature radius/thickness ratio of 4.2 in a rolling (L) direction with respect to an axis extending in a width (C) direction, an L cross section in a 0- to 50-µm region from a surface of the steel sheet on a compression side has a number density of voids of 1500 /mm2 or less, and the galvanized steel sheet has a tensile strength of 980 MPa or more.