公开(公告)号：US20240183017A1

公开(公告)日：2024-06-06

申请号：US18285505

申请日：2022-05-10

Applicant: NIPPON STEEL CORPORATION

Inventor： Yuri TODA ,  Daisuke MAEDA ,  Tamaki SUZUKI ,  Ko SATAKE ,  Yuma ASADA

IPC: C22C38/60 ,  B21D22/02 ,  C21D8/02 ,  C21D9/46 ,  C22C38/00 ,  C22C38/20 ,  C22C38/22 ,  C22C38/24 ,  C22C38/26 ,  C22C38/28 ,  C22C38/30 ,  C22C38/32 ,  C22C38/44 ,  C22C38/48 ,  C22C38/50 ,  C22C38/54

CPC classification number: C22C38/60 ,  B21D22/022 ,  C21D8/0205 ,  C21D8/0226 ,  C21D8/0236 ,  C21D8/0263 ,  C21D9/46 ,  C22C38/001 ,  C22C38/002 ,  C22C38/005 ,  C22C38/008 ,  C22C38/20 ,  C22C38/22 ,  C22C38/24 ,  C22C38/26 ,  C22C38/28 ,  C22C38/30 ,  C22C38/32 ,  C22C38/44 ,  C22C38/48 ,  C22C38/50 ,  C22C38/54 ,  C21D2211/001 ,  C21D2211/005 ,  C21D2211/009

Abstract: This hot-stamping formed body has a predetermined chemical composition and has a microstructure in which an average grain size of prior austenite grains is 5 to 25 μm, and a standard deviation of grain sizes of the prior austenite grains is 0.1 to 2.0 μm. In addition, this steel sheet for hot stamping has a predetermined chemical composition and has a microstructure in which an average value of the pole densities of ferrite in the orientation group consisting of {100} to {223} is 10.0 or less, in entire ferrite, a number proportion of ferrite containing a carbide having an equivalent circle diameter of 0.2 μm or more in grains is 20% or more, and the steel sheet for hot stamping has a microstructure in which an area ratio of pearlite is 10% to 90% and an ratio of ferrite is 10% to 90%.

公开(公告)号：US20250146111A1

公开(公告)日：2025-05-08

申请号：US18837633

申请日：2023-03-02

Applicant: NIPPON STEEL CORPORATION

Inventor： Yuma ASADA ,  Yuri TODA ,  Yasuyuki OGISU ,  Tamaki SUZUKI

IPC: C22C38/38 ,  C22C38/00 ,  C22C38/02 ,  C22C38/04 ,  C22C38/06 ,  C22C38/22 ,  C22C38/26 ,  C22C38/28 ,  C22C38/32

Abstract: Provided is a steel sheet for hot stamping having a predetermined chemical composition and a metallographic structure comprising, by area ratio, ferrite: 10% or more and pearlite: 10% or more, wherein a total of ferrite and pearlite is 80% or more, and a dispersion index of pearlite is 0.50 or more. Further, provided is a hot stamped part having a predetermined chemical composition and a metallographic structure comprising, by area ratio, at least one of martensite, bainite, and tempered martensite in a total of 90% or more, wherein a standard deviation in a hardness distribution of prior austenite grains at a sheet thickness ¼ position is 150 Hv or less.

公开(公告)号：US20250101557A1

公开(公告)日：2025-03-27

申请号：US18832024

申请日：2023-03-02

Applicant: NIPPON STEEL CORPORATION

Inventor： Yuri TODA ,  Shingo FUJINAKA ,  Jun HAGA ,  Yuma ASADA

IPC: C22C38/38 ,  C22C38/00 ,  C22C38/02 ,  C22C38/06 ,  C22C38/22 ,  C22C38/26 ,  C22C38/28 ,  C22C38/32

Abstract: This hot-stamping formed body has a predetermined chemical composition, in an interior region, a standard deviation of grain sizes of prior austenite grains of 5.0 μm or less, in a surface layer region, an area ratio of bainite of more than 10%, a maximum value of pole density of a texture of 4.0 or less, and a deboronization index of 0.05 or more.

公开(公告)号：US20250034686A1

公开(公告)日：2025-01-30

申请号：US18716021

申请日：2023-03-02

Applicant: NIPPON STEEL CORPORATION

Inventor： Yuri TODA ,  Kazuma ITO ,  Yuma ASADA

IPC: C22C38/38 ,  C22C38/00 ,  C22C38/02 ,  C22C38/06 ,  C22C38/22 ,  C22C38/26 ,  C22C38/28 ,  C22C38/32

Abstract: Provided is a hot stamped body having a predetermined chemical composition and a microstructure comprising, by area ratio, at least one of martensite, bainite, and tempered martensite: 90% or more in total, wherein a standard deviation in grain size distribution of former austenite grains is 5.0 μm or less, and a total amount of segregation of at least one of Mo, W, Ta, Re, Os, Ir, and Tc at the former austenite grain boundaries is 0.10 atm % or more.

公开(公告)号：US20240183015A1

公开(公告)日：2024-06-06

申请号：US18279370

申请日：2022-05-09

Applicant: NIPPON STEEL CORPORATION

Inventor： Yuri TODA ,  Daisuke MAEDA ,  Tamaki SUZUKI ,  Yuma ASADA ,  Takuya TAKAYAMA

IPC: C22C38/38 ,  C21D9/46 ,  C22C38/02 ,  C22C38/06

CPC classification number: C22C38/38 ,  C21D9/46 ,  C22C38/02 ,  C22C38/06 ,  C21D2211/001 ,  C21D2211/002 ,  C21D2211/005

Abstract: This steel sheet for hot stamping has a predetermined chemical composition and has a microstructure in which Sα+SGB, which is a total of an area ratio Sα of ferrite and an area ratio SGB of a granular bainite, is 10% or more and less than 50% and SGB/Sα, which is a ratio between the area ratio SGB of the granular bainite and the area ratio Sα of the ferrite, is 0.30 to 0.70. In addition, a hot-stamping formed body manufactured using this steel sheet for hot stamping has a predetermined chemical composition and a microstructure in which an average grain size of prior austenite grains is 5 to 25 μm, and a standard deviation of grain sizes of the prior austenite grains is 0.1 to 2.0 μm, and a tensile strength of the hot-stamping formed body is 2,200 MPa or more.