公开(公告)号：US20250144693A1

公开(公告)日：2025-05-08

申请号：US18835697

申请日：2022-02-03

Applicant: NIPPON STEEL CORPORATION

Inventor： Yoshiaki HONDA ,  Yuji SAKIYAMA ,  Takashi YASUTOMI ,  Masahiro NAKATA

IPC: B21D28/00

Abstract: A steel material reduced in tensile residual stress at a sheared edge, in particular a fractured surface, is disclosed. The steel material of the present disclosure has a sheared edge, the sheared edge has a rollover, a fractured surface, and a burr, the fractured surface includes a first part and a second part, the first part is formed by a first crack propagating from the rollover side to the burr side, the second part is formed by a second crack propagating from the burr side to the rollover side, and an area ratio of the first part in the fractured surface is greater than an area ratio of the second part in the fractured surface.

公开(公告)号：US20230250521A1

公开(公告)日：2023-08-10

申请号：US18008639

申请日：2021-08-06

Applicant: NIPPON STEEL CORPORATION

Inventor： Yuji SAKIYAMA ,  Takashi YASUTOMI ,  Katsuya NAKANO ,  Yoshiaki HONDA ,  Masahiro NAKATA

IPC: C22C38/02 ,  C22C38/04 ,  C22C38/06 ,  C22C38/60 ,  C22C38/00 ,  C22C38/22 ,  C22C38/32 ,  C22C38/46 ,  C22C38/48 ,  C22C38/42 ,  B32B15/01

CPC classification number: C22C38/02 ,  C22C38/04 ,  C22C38/06 ,  C22C38/60 ,  C22C38/001 ,  C22C38/22 ,  C22C38/32 ,  C22C38/46 ,  C22C38/48 ,  C22C38/42 ,  B32B15/011 ,  B32B2311/30 ,  B32B2307/536 ,  B32B2307/54

Abstract: Provided is a steel sheet comprising a sheet thickness center part and a first surface layer part and a second surface layer part respectively arranged at two sides of the sheet thickness center part, wherein the first surface layer part and second surface layer part respectively independently have thicknesses of more than 10 μm to 30% or less of the sheet thickness, the first surface layer part and second surface layer part have average Vickers hardnesses different from the average Vickers hardness of a sheet thickness ½ position, and a first hardness cumulative value at a region from a surface of the first surface layer part side to 30% of the sheet thickness is 1.05 times or more of a second hardness cumulative value at a region from a surface of the second surface layer part side to 30% of the sheet thickness.

公开(公告)号：US20220228244A1

公开(公告)日：2022-07-21

申请号：US17613327

申请日：2020-05-28

Applicant: NIPPON STEEL CORPORATION

Inventor： Yuji SAKIYAMA ,  Yuri TODA ,  Tomohito TANAKA ,  Kazuo HIKIDA

IPC: C22C38/32 ,  B32B15/01 ,  C22C38/28 ,  C22C38/26 ,  C22C38/22 ,  C22C38/06 ,  C22C38/04 ,  C22C38/02 ,  C22C38/00 ,  C22C18/00 ,  C21D9/46 ,  C21D8/02 ,  C21D6/00

Abstract: A hot-stamped article according to the present invention has a plating layer being attached 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 an impurity on a surface of a base steel sheet having a predetermined chemical composition, a surface layer region includes 90.0 % or more of martensite in terms of area percentage, and a concentration of Ni in a prior austenite grain boundary in the surface layer region is 5.5 mass % or more.

公开(公告)号：US20250092496A1

公开(公告)日：2025-03-20

申请号：US18729628

申请日：2023-03-03

Applicant: NIPPON STEEL CORPORATION

Inventor： Miyuri UMEHARA ,  Yukiko KOBAYASHI ,  Shunsuke TANIGUCHI ,  Naoki MATSUI ,  Shingo YAMASAKI ,  Yuji SAKIYAMA

IPC: C22C38/22 ,  C22C38/00 ,  C22C38/02 ,  C22C38/04 ,  C22C38/06 ,  C22C38/24

Abstract: A steel material according to the present disclosure consists of, by mass %, C: 0.30 to 0.50%, Si: 0.01 to 0.30%, Mn: 0.10 to 1.50%, P: 0.030% or less, S: 0.030% or less, Cr: 0.01 to 0.80%, Mo: 0.70 to less than 1.50%, V: 0.01 to 0.50%, Al: 0.005 to 0.100%, and N: 0.0010 to 0.0300%, with the balance being Fe and impurities. The area fraction of hard structure is 90% or more and the Vickers hardness is 220 to 400 HV. The number density of cementite particles in the hard structure is 4.0 pieces/μm2 or more. The number ratio of cementite particles having an area of 0.0005 to 0.0100 μm2 among a plurality of the cementite particles in the hard structure is 50.0% or more. The sample standard deviation of the areas of a plurality of the cementite particles in the hard structure is 0.070 μm2 or less.

公开(公告)号：US20230257844A1

公开(公告)日：2023-08-17

申请号：US18012882

申请日：2021-08-06

Applicant: NIPPON STEEL CORPORATION

Inventor： Katsuya NAKANO ,  Yuji SAKIYAMA ,  Takashi YASUTOMI ,  Yoshiaki HONDA ,  Masahiro NAKATA

IPC: C21D9/46 ,  C21D8/02 ,  C21D6/00 ,  C22C38/60 ,  C22C38/14 ,  C22C38/12 ,  C22C38/16 ,  C22C38/06 ,  C22C38/04 ,  C22C38/02 ,  C22C38/00 ,  C22C38/10 ,  C22C38/08 ,  C22C38/18 ,  C21D3/04

CPC classification number: C21D9/46 ,  C21D8/0205 ,  C21D8/0226 ,  C21D8/0236 ,  C21D6/005 ,  C21D6/008 ,  C22C38/60 ,  C22C38/14 ,  C22C38/12 ,  C22C38/16 ,  C22C38/06 ,  C22C38/04 ,  C22C38/02 ,  C22C38/008 ,  C22C38/002 ,  C22C38/10 ,  C22C38/08 ,  C22C38/18 ,  C22C38/001 ,  C22C38/005 ,  C21D3/04 ,  C21D8/0257

Abstract: Provided is a steel sheet comprising a sheet thickness center part and a first surface layer softened part and a second surface layer softened part respectively arranged at two sides of the sheet thickness center part, wherein the first surface layer softened part and second surface layer softened part have 10 μm or more average thicknesses and have average Vickers hardnesses of 0.90 time or less of the average Vickers hardness of a sheet thickness ½ position, and the first surface layer softened part has an average Vickers hardness of 1.05 times or more the average Vickers hardness of the second surface layer softened part.

公开(公告)号：US20230078655A1

公开(公告)日：2023-03-16

申请号：US17801963

申请日：2021-05-13

Applicant: NIPPON STEEL CORPORATION

Inventor： Yuji SAKIYAMA ,  Akinobu KOBAYASHI ,  Takayuki HARANO

IPC: C21D9/46 ,  B21D22/02 ,  C22C38/02 ,  C22C38/04 ,  C22C38/06 ,  C22C38/00 ,  C22C38/60 ,  C25D3/44 ,  C25D3/12 ,  C23C28/00 ,  C22C21/02

Abstract: This steel sheet for hot stamping includes a base material, an Al—Si alloy plating layer in which the Al content is 75 mass % or more, the Si content is 3 mass % or more and the total of the Al content and the Si content is 95 mass % or more, an Al oxide coating having a thickness of 0 to 20 nm and a Ni plating layer in which the Ni content is more than 90 mass % in this order, the base material has a predetermined chemical composition, the Al—Si alloy plating layer has a thickness of 7 to 148 μm, and the Ni plating layer has a thickness of more than 200 nm and 2500 nm or less.

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：US20230182190A1

公开(公告)日：2023-06-15

申请号：US17910749

申请日：2021-05-13

Applicant: NIPPON STEEL CORPORATION

Inventor： Akinobu KOBAYASHI ,  Yuji SAKIYAMA ,  Takayuki HARANO

IPC: B21D22/02 ,  C22C38/06 ,  C22C38/04 ,  C22C38/02

CPC classification number: B21D22/022 ,  C22C38/06 ,  C22C38/04 ,  C22C38/02

Abstract: This hot stamping member is a hot stamping member including a base material and a plating layer provided on the base material, in which the plating layer has a Ni-rich region, an Al-rich region and an Fe-rich region in this order from a surface of the plating layer, in a region from the surface of the plating layer to a 100 nm position in the thickness direction from the surface of the plating layer, Ni and Fe satisfy predetermined contents, in a region from the 100 nm position in the thickness direction from the surface of the plating layer to a 500 nm position in the thickness direction from the surface of the plating layer, Ni and Fe satisfy predetermined contents, and, in a region from the 500 nm position in the thickness direction from the surface of the plating layer to a 1000 nm position in the thickness direction from the surface of the plating layer, Ni and Fe satisfy predetermined contents.

公开(公告)号：US20230093517A1

公开(公告)日：2023-03-23

申请号：US17802569

申请日：2021-05-13

Applicant: NIPPON STEEL CORPORATION

Inventor： Takayuki HARANO ,  Yuji SAKIYAMA ,  Akinobu KOBAYASHI

IPC: B32B15/01 ,  B21D22/02 ,  C22C21/02 ,  C22C38/38 ,  C22C38/26 ,  C22C38/16 ,  C22C38/14 ,  C22C38/08 ,  C22C38/06 ,  C22C38/02 ,  C22C38/00

Abstract: This steel sheet for hot stamping includes a base material, an Al-Si alloy plating layer in which the Al content is 75 mass% or more, the Si content is 3 mass% or more and the total of the Al content and the Si content is 95 mass% or more and a Ni plating layer in which the Ni content is more than 90 mass% in this order, the chemical composition of the base material is, by mass%, C: 0.01% or more and less than 0.70%, Si: 0.005% to 1.000%, Mn: 0.40% to 3.00%, Nb: 0.010% to 0.200%, a solid solution of Nb: 0.010% to 0.150%, sol. A1: 0.00020% to 0.50000%, P: 0.100% or less, S: 0.1000% or less, N: 0.0100% or less, Cu: 0% to 1.00%, Ni: 0% to 1.00%, V: 0% to 1.00%, Ti: 0% to 0.150%, Mo: 0% to 1.000%, Cr: 0% to 1.000%, B: 0% to 0.0100%, Ca: 0% to 0.010%. REM: 0% to 0.300%, and a remainder: Fe and an impurity, the Al-Si alloy plating layer has a thickness of 7 to 148 µm, and the Ni plating layer has a thickness of more than 200 nm and 2500 nm or less.

公开(公告)号：US20220227105A1

公开(公告)日：2022-07-21

申请号：US17614415

申请日：2020-05-28

Applicant: NIPPON STEEL CORPORATION

Inventor： Yuji SAKIYAMA ,  Yuri TODA ,  Kazuo HIKIDA

IPC: B32B15/01 ,  C22C18/00 ,  C22C38/28 ,  C22C38/12 ,  C22C38/06 ,  C22C38/04 ,  C22C38/02 ,  C22C38/00 ,  C21D9/46 ,  C21D8/02 ,  C21D6/00

Abstract: A steel sheet for hot stamping according to the present invention has a plating layer being attached 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, 15.0% or more of the crystal grains of one or two kinds of unauto-tempered martensite and lower bainite are included in terms of area percentage, and the average dislocation density is 4×1015 m/m3.