公开(公告)号：US12091723B2

公开(公告)日：2024-09-17

申请号：US18011090

申请日：2021-06-30

Applicant: JFE STEEL CORPORATION

Inventor： Shinsuke Komine ,  Tatsuya Nakagaito ,  Kentaro Sato ,  Tomohiro Sakaidani

IPC: C22C33/04 ,  B23K11/00 ,  B23K11/11 ,  B23K11/16 ,  B32B15/01 ,  B32B15/04 ,  B32B15/18 ,  C21D1/18 ,  C21D1/19 ,  C21D1/25 ,  C21D6/00 ,  C21D8/02 ,  C21D9/46 ,  C22C38/00 ,  C22C38/02 ,  C22C38/04 ,  C22C38/06 ,  C22C38/08 ,  C22C38/12 ,  C22C38/14 ,  C22C38/16 ,  C22C38/18 ,  C22C38/20 ,  C22C38/22 ,  C22C38/24 ,  C22C38/26 ,  C22C38/28 ,  C22C38/32 ,  C22C38/34 ,  C22C38/38 ,  C22C38/40 ,  C22C38/42 ,  C22C38/44 ,  C22C38/46 ,  C22C38/48 ,  C22C38/50 ,  C22C38/54 ,  C22C38/58 ,  C22C38/60 ,  C23C2/02 ,  C23C2/06 ,  C23C2/28 ,  C23C2/40 ,  C23C28/00 ,  C23C28/02 ,  C23C30/00 ,  C25D3/22 ,  C25D5/36 ,  C25D5/50 ,  C25D7/06 ,  B23K101/00 ,  B23K101/28 ,  B23K101/34 ,  B23K103/04

CPC classification number: C21D9/46 ,  B23K11/0026 ,  B23K11/11 ,  B23K11/166 ,  B32B15/013 ,  B32B15/015 ,  B32B15/04 ,  B32B15/043 ,  B32B15/18 ,  C21D1/18 ,  C21D1/185 ,  C21D1/19 ,  C21D1/25 ,  C21D6/001 ,  C21D6/002 ,  C21D6/005 ,  C21D6/008 ,  C21D8/0205 ,  C21D8/0226 ,  C21D8/0236 ,  C21D8/0263 ,  C21D8/0273 ,  C21D8/0278 ,  C22C33/04 ,  C22C38/001 ,  C22C38/002 ,  C22C38/005 ,  C22C38/008 ,  C22C38/02 ,  C22C38/04 ,  C22C38/06 ,  C22C38/08 ,  C22C38/12 ,  C22C38/14 ,  C22C38/16 ,  C22C38/18 ,  C22C38/20 ,  C22C38/22 ,  C22C38/24 ,  C22C38/26 ,  C22C38/28 ,  C22C38/32 ,  C22C38/34 ,  C22C38/38 ,  C22C38/40 ,  C22C38/42 ,  C22C38/44 ,  C22C38/46 ,  C22C38/48 ,  C22C38/50 ,  C22C38/54 ,  C22C38/58 ,  C22C38/60 ,  C23C2/02 ,  C23C2/0224 ,  C23C2/06 ,  C23C2/28 ,  C23C2/285 ,  C23C2/29 ,  C23C2/40 ,  C23C28/021 ,  C23C28/025 ,  C23C28/3225 ,  C23C30/00 ,  C23C30/005 ,  C25D3/22 ,  C25D5/36 ,  C25D5/50 ,  C25D7/0614 ,  B23K2101/006 ,  B23K2101/28 ,  B23K2101/34 ,  B23K2103/04 ,  C21D2211/001 ,  C21D2211/002 ,  C21D2211/005 ,  C21D2211/008 ,  Y10T428/12792 ,  Y10T428/12951 ,  Y10T428/12958 ,  Y10T428/12965 ,  Y10T428/12972

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：US12241875B2

公开(公告)日：2025-03-04

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 ,  G01N3/04 ,  G01N3/06 ,  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：US20220106662A1

公开(公告)日：2022-04-07

申请号：US17425096

申请日：2019-10-18

Applicant: JFE Steel Corporation

Inventor： Shinsuke Komine ,  Tatsuya Nakagaito ,  Kentaro Sato ,  Tomohiro Sakaidani

IPC: C21D9/46 ,  B32B15/01 ,  C21D8/02 ,  C21D6/00 ,  C23C2/40 ,  C23C2/06 ,  C22C38/58 ,  C22C38/54 ,  C22C38/50 ,  C22C38/48 ,  C22C38/44 ,  C22C38/42 ,  C22C38/06 ,  C22C38/02 ,  C22C38/00 ,  C22C38/46

Abstract: The high-strength hot-dip galvanized steel sheet, which includes a hot-dip galvanized coating layer on a surface of the steel sheet, has a component composition containing, in mass %, C: 0.07% to 0.20%, Si: 0.1% to 2.0%, Mn: 2.0% to 3.5%, P: 0.05% or less, S: 0.05% or less, and sol. Al: 0.005% to 0.1%, with the balance being Fe and incidental impurities; and has a steel microstructure containing, in area fraction, 60% or less of ferrite, 40% or more of tempered martensite, and 10% or less of fresh martensite and having a void number density of 1,500/mm2 or less in a bent portion in the VDA bending test.

公开(公告)号：US11976341B2

公开(公告)日：2024-05-07

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 ,  C21D8/02 ,  C22C38/00 ,  C22C38/02 ,  C22C38/04 ,  C22C38/06 ,  C22C38/60 ,  C23C2/06 ,  C23C2/40 ,  C25D3/22

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

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：US11643701B2

公开(公告)日：2023-05-09

申请号：US17425096

申请日：2019-10-18

Applicant: JFE Steel Corporation

Inventor： Shinsuke Komine ,  Tatsuya Nakagaito ,  Kentaro Sato ,  Tomohiro Sakaidani

IPC: C21D9/46 ,  B32B15/01 ,  C21D6/00 ,  C21D8/02 ,  C22C38/00 ,  C23C2/06 ,  C23C2/40 ,  C22C38/02 ,  C22C38/06 ,  C22C38/42 ,  C22C38/44 ,  C22C38/46 ,  C22C38/48 ,  C22C38/50 ,  C22C38/54 ,  C22C38/58

CPC classification number: C21D9/46 ,  B32B15/013 ,  C21D6/004 ,  C21D6/005 ,  C21D6/008 ,  C21D8/0205 ,  C21D8/0226 ,  C21D8/0236 ,  C21D8/0263 ,  C22C38/001 ,  C22C38/002 ,  C22C38/005 ,  C22C38/02 ,  C22C38/06 ,  C22C38/42 ,  C22C38/44 ,  C22C38/46 ,  C22C38/48 ,  C22C38/50 ,  C22C38/54 ,  C22C38/58 ,  C23C2/06 ,  C23C2/40 ,  C21D2211/001 ,  C21D2211/005 ,  C21D2211/008

Abstract: The high-strength hot-dip galvanized steel sheet, which includes a hot-dip galvanized coating layer on a surface of the steel sheet, has a component composition containing, in mass %, C: 0.07% to 0.20%, Si: 0.1% to 2.0%, Mn: 2.0% to 3.5%, P: 0.05% or less, S: 0.05% or less, and sol. Al: 0.005% to 0.1%, with the balance being Fe and incidental impurities; and has a steel microstructure containing, in area fraction, 60% or less of ferrite, 40% or more of tempered martensite, and 10% or less of fresh martensite and having a void number density of 1,500/mm2 or less in a bent portion in the VDA bending test.

公开(公告)号：US11332804B2

公开(公告)日：2022-05-17

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 ,  C22C38/00 ,  C22C38/02 ,  C22C38/04 ,  C22C38/06 ,  C22C38/10 ,  C22C38/12 ,  C22C38/14 ,  C22C38/20 ,  C22C38/32 ,  C22C38/60 ,  C23C2/06

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.