公开(公告)号：US20220234330A1

公开(公告)日：2022-07-28

申请号：US17614400

申请日：2020-05-28

Applicant: NIPPON STEEL CORPORATION

Inventor： Yuji SAKIYAMA ,  Yuri TODA ,  Kazuo HIKIDA

IPC: B32B15/01 ,  C22C18/00 ,  C22C38/18 ,  C22C38/14 ,  C22C38/12 ,  C22C38/06 ,  C22C38/04 ,  C22C38/02 ,  C22C38/00 ,  C21D9/46 ,  C21D8/02 ,  C21D6/00

Abstract: A hot-stamped article according to the present invention has a plating layer being attached to a single surface in an amount of 10 g/m2 or more and 90 g/m2 or less and having a Ni content of 10 mass % or more and 25 mass % or less with a remainder including Zn and impurities on a surface of a base steel sheet having a predetermined chemical composition, in a surface layer region, a metallographic structure includes 80.0% or more of martensite and 8.0% or more of residual austenite in terms of area percentage, and the concentration of Ni in the surface layer region is 8 mass % or more.

公开(公告)号：US20220170128A1

公开(公告)日：2022-06-02

申请号：US17442334

申请日：2020-05-13

Applicant: NIPPON STEEL CORPORATION

Inventor： Daisuke MAEDA ,  Yuri TODA ,  Kazuo HIKIDA

IPC: C21D9/46 ,  C22C38/00 ,  C22C38/02 ,  C22C38/04 ,  C22C38/06 ,  C22C38/22 ,  C22C38/26 ,  C22C38/28 ,  C22C38/32 ,  C22C38/60 ,  C23C2/06 ,  C23C2/40 ,  C21D8/02

Abstract: A steel sheet for hot stamping includes: a steel sheet having a predetermined chemical composition; and a plating layer provided on a surface of the steel sheet, the plating layer having an adhesion amount of 10 g/m2 to 90 g/m2 and a Ni content of 10 mass % to 25 mass %, and containing a remainder consisting of Zn and impurities. The steel sheet for hot stamping includes, in a surface layer region of the steel sheet, 80% or more by area % of grains having an average crystal orientation difference of 0.4° to 3.0° inside grains surrounded by grain boundaries having an average crystal orientation difference of 5° or more.

公开(公告)号：US20220161857A1

公开(公告)日：2022-05-26

申请号：US17437365

申请日：2020-03-27

Applicant: NIPPON STEEL CORPORATION

Inventor： Yuri TODA ,  Hiroaki KUBOTA

IPC: B62D21/15 ,  B62D25/02

Abstract: This frame member includes a corner section extending along the longitudinal direction; a first wall section extending from an end portion of the corner section in a direction orthogonal to the longitudinal direction; and a second wall section extending from an opposite end portion of the corner section, wherein the corner section is formed with a deformation starting portion from which a deformation starts when a load is input to the frame member in the longitudinal direction, the deformation starting portion having a shape protruding to an inner bending side or an outer bending side of the corner section, and an average hardness value H(K1) at a first region is equal to or greater than 330 Hv in Vickers hardness, and a 3-sigma range of a standard deviation σ in a frequency distribution of the hardness at the first region is equal to or greater than 60, the first region being located at a portion outwardly apart from an end portion of the deformation starting portion in the longitudinal direction by 10 mm in the longitudinal direction, at a depth of ¼ thickness of the frame member from a surface.

公开(公告)号：US20220127705A1

公开(公告)日：2022-04-28

申请号：US17424119

申请日：2020-03-19

Applicant: NIPPON STEEL CORPORATION

Inventor： Shingo FUJINAKA ,  Yuri TODA ,  Daisuke MAEDA

IPC: C22C38/32 ,  B21D22/02 ,  B32B15/01 ,  C22C38/30 ,  C22C38/28 ,  C22C38/26 ,  C22C38/22 ,  C22C38/06 ,  C22C38/04 ,  C22C38/02 ,  C22C38/00 ,  C21D8/00 ,  C21D6/00

Abstract: A hot-stamping formed body has a predetermined chemical composition and a microstructure including, by area ratio, 90% to 100% of martensite and 0% to 10% of a remainder in the microstructure. In the microstructure, a region in which an average GAIQ value in a unit grain is 60,000 or more is 30 area % or more, and a number density of carbides having a circle equivalent diameter of 0.20 μm or more is 50/mm2 or less.

公开(公告)号：US20220119929A1

公开(公告)日：2022-04-21

申请号：US17431324

申请日：2020-03-19

Applicant: NIPPON STEEL CORPORATION

Inventor： Shingo FUJINAKA ,  Yuri TODA ,  Daisuke MAEDA

IPC: C22C38/58 ,  C22C38/02 ,  C22C38/06 ,  C22C38/00 ,  C22C38/54 ,  C22C38/52 ,  C22C38/50 ,  C22C38/46 ,  C22C38/48 ,  C22C38/44 ,  B21D22/02

Abstract: A hot-stamping formed body has a predetermined chemical composition, in which an average grain size of prior austenite grains in a microstructure is 5.0 μm or less, and an average Mn concentration at grain boundaries of the prior austenite grains is 1.0 mass % or less. The hot-stamping formed body may be provided with a plating layer on the surface thereof, or may have a softened region in a portion thereof.

公开(公告)号：US20250043406A1

公开(公告)日：2025-02-06

申请号：US18719744

申请日：2023-03-02

Applicant: NIPPON STEEL CORPORATION

Inventor： Kazuma ITO ,  Shinichiro TABATA ,  Yuri TODA

IPC: C22C38/60 ,  C22C38/00 ,  C22C38/02 ,  C22C38/04 ,  C22C38/06 ,  C22C38/20 ,  C22C38/22 ,  C22C38/24 ,  C22C38/26 ,  C22C38/28 ,  C22C38/30 ,  C22C38/32 ,  C22C38/34 ,  C22C38/44 ,  C22C38/48 ,  C22C38/50 ,  C22C38/54

Abstract: Provided is a hot stamped body having a chemical composition comprising, by mass %, C: 0.40 to 0.70%, P: 0.100% or less, S: 0.0100% or less, N: 0.0200% or less, O: 0.0200% or less, Al: 0.0010 to 0.500%, Nb: 0.0010 to 0.100%, Ti: 0.010 to 0.200%, Mo: 0.010 to 2.000%, B: 0.0005 to 0.0200%, etc., and balance of Fe and impurities, and a microstructure with a total amount of segregation of at least one of Mo, W, Ta, Re, Os, Ir, and Tc at prior austenite grain boundaries of 0.10 atm % or more.

公开(公告)号：US20240058887A1

公开(公告)日：2024-02-22

申请号：US18269784

申请日：2022-04-14

Applicant: NIPPON STEEL CORPORATION

Inventor： Ryoma KATO ,  Takahiro AITOH ,  Shingo FUJINAKA ,  Yuri TODA

IPC: B23K11/11

CPC classification number: B23K11/11 ,  B23K2103/04

Abstract: Provided is a frame member obtained by joining a first steel sheet member and a second steel sheet member at a spot-welding portion by spot welding. A cross-sectional region in which a cross section perpendicular to a longitudinal direction of the frame member is a closed cross section is formed, the first steel sheet member has a tensile strength of 1,900 MPa or more, and the spot-welding portion has a molten metal portion formed by the spot welding and a heat-affected portion adjacent to an outside of the molten metal portion. Average Vickers hardness HvAve at a measurement position corresponding to the first region on the virtual straight line and minimum Vickers hardness HvMin at a measurement position corresponding to the third region on the virtual straight line satisfy HvAve−HvMin≤100.

公开(公告)号：US20240011113A1

公开(公告)日：2024-01-11

申请号：US18026022

申请日：2021-10-15

Applicant: NIPPON STEEL CORPORATION

Inventor： Masafumi AZUMA ,  Yuri TODA ,  Kenichiro OTSUKA

IPC: C21D9/46 ,  C22C38/38 ,  C22C38/32 ,  C22C38/28 ,  C22C38/26 ,  C22C38/16 ,  C22C38/14 ,  C22C38/12 ,  C22C38/08 ,  C22C38/06 ,  C22C38/04 ,  C22C38/02 ,  C22C38/00 ,  C21D8/02 ,  C21D6/00 ,  C21D1/84 ,  B21D22/02

CPC classification number: C21D9/46 ,  C22C38/38 ,  C22C38/32 ,  C22C38/28 ,  C22C38/26 ,  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 ,  C21D8/0278 ,  C21D8/0263 ,  C21D6/001 ,  C21D6/002 ,  C21D6/005 ,  C21D6/008 ,  C21D1/84 ,  B21D22/022 ,  C21D2211/002 ,  C21D2211/005 ,  C21D2211/008 ,  C21D2211/009

Abstract: A steel sheet for hot stamping includes, as a chemical composition, by mass %: C: 0.060% to 0.120%; Si: 0% to 0.70%; Mn: 1.60% to 3.00%; P: 0.100% or less; S: 0.0100% or less; N: 0.0100% or less; Al: 0.001% to 0.100%; Ti: 0.005% to 0.050%; and B: 0.0005% to 0.0100%. If necessary, the chemical composition contains one or two or more selected from the group consisting of Nb, V, W, Ni, Cu, Mo, Sn, Ca, Mg, and REM and a remainder of Fe and impurities, A microstructure includes 70% or more of upper bainite by area ratio, and a number density of iron carbides having a major axis of 0.01 μm or more included in the upper bainite is equal to or greater than 4/μm2.

公开(公告)号：US20230001466A1

公开(公告)日：2023-01-05

申请号：US17781325

申请日：2021-01-08

Applicant: NIPPON STEEL CORPORATION

Inventor： Yuri TODA ,  Kodai MURASAWA ,  Daisuke MAEDA ,  Kazuo HIKIDA

IPC: B21D22/02 ,  C22C38/00 ,  C22C38/02 ,  C22C38/04 ,  C22C38/06 ,  C22C38/10 ,  C22C38/60 ,  C21D1/18

Abstract: A hot-stamping formed body has a predetermined chemical composition and includes microstructure which includes residual austenite of which an area ratio is 10% or more and less than 20%, Among grain boundaries of crystal grains of bainite and tempered martensite a ratio of a length of a grain boundary having a rotation angle in a range of 55° to 75° to a total length of a grain boundary having a rotation angle in a range of 4° to 12°, a grain boundary having a rotation angle in a range of 49° to 54°, and the grain boundary having a rotation angle in, a range of 55° to 75° to the direction as a rotation axis is 30% or more.

公开(公告)号：US20210115544A1

公开(公告)日：2021-04-22

申请号：US17042319

申请日：2018-03-29

Applicant: NIPPON STEEL CORPORATION

Inventor： Yuri TODA ,  Kazuo HIKIDA ,  Shingo FUJINAKA ,  Tomohito TANAKA

IPC: C22C38/58 ,  C22C38/48 ,  C22C38/44 ,  C22C38/50 ,  C22C38/02 ,  C22C38/06 ,  C22C38/54 ,  C21D9/46

Abstract: A steel sheet for hot stamping use used as a material for a hot stamped article excellent in strength or bending deformability, having a predetermined chemical composition, having a microstructure containing at least one of lower bainite, martensite, and tempered martensite in an area ratio of 90% or more, having an X-ray random intensity ratio of {112} of the crystal grains forming the above lower bainite, martensite, or tempered martensite of 2.8 or more, having a number density of grain size 50 nm or less cementite or epsilon carbides in the microstructure of 1×1016/cm3 or more, and having a grain boundary solid solution ratio Z defined by Z=(mass % of one or both of Nb and Mo at grain boundaries)/(mass % of one or both of Nb and Mo at time of melting) of 0.4 or more.