公开(公告)号：US20240150901A1

公开(公告)日：2024-05-09

申请号：US18280553

申请日：2021-04-08

Applicant: NIPPON STEEL CORPORATION

Inventor： Yuki SUZUKI ,  Kenta UENISHI ,  Soshi FUJITA ,  Masahiro FUDA

IPC: C23C28/00

CPC classification number: C23C28/3455

Abstract: To provide a steel sheet for hot stamping that further improves productivity of a hot-stamped member, has excellent appearance, and has excellent spot weldability, and a hot-stamped member. A steel sheet for hot stamping according to the present invention includes, on the whole of at least one surface of the steel sheet, a surface-treated film whose emissivity at a wavelength of 8.0 μm at 25° C. is 60% or more, in which the surface-treated film contains carbon black, and one or more of oxides selected from a group consisting of a Zr oxide, a Zn oxide, and a Ti oxide, in which the carbon black and the oxides exist while being dispersed over the entire surface-treated film, the surface-treated film has a silica content of 0 to 0.3 g/m2, and when an adhesion amount of the carbon black and an adhesion amount of the oxides are set to XCB (g/m2) and XOxide (g/m2), respectively, an equation (1) is satisfied.

公开(公告)号：US20240068080A1

公开(公告)日：2024-02-29

申请号：US18261885

申请日：2022-03-14

Applicant: NIPPON STEEL CORPORATION

Inventor： Takashi DOI ,  Kenji KOBAYASHI ,  Naomi INATOMI ,  Yuki SUZUKI ,  Soshi FUJITA ,  Masahiro FUDA

IPC: C23C2/12 ,  C22C38/00 ,  C22C38/02 ,  C22C38/04 ,  C22C38/06 ,  C22C38/14 ,  C23C2/28 ,  C23C2/40

CPC classification number: C23C2/12 ,  C22C38/001 ,  C22C38/002 ,  C22C38/02 ,  C22C38/04 ,  C22C38/06 ,  C22C38/14 ,  C23C2/28 ,  C23C2/40

Abstract: A hot-stamped product with improved delayed-fracture resistance is provided. The hot-stamped product 1 includes: a steel substrate 10; and an Al film 20 formed on the steel substrate 10, the Al film 20 including: an interface layer 21 located at the interface with the steel substrate 10 and with part of the αFe substituted by Al and Si; an intermediate layer 22 formed on the interface layer 21; and an oxide layer formed on the intermediate layer, the intermediate layer 22 including an Fe—Al—Si phase 22a with part of the αFe substituted by Al and Si, the Fe—Al—Si phase 22a including one or more elements selected from the group consisting of Zr, Ce, Y, Ta, Ni, Cu, Nb, Cr, Co, V and Ti, the oxide layer 23 including one or more elements selected from the group consisting of Be, Mg, Ca, Sr, Ba, Sc and Zn.

公开(公告)号：US20240044012A1

公开(公告)日：2024-02-08

申请号：US18277550

申请日：2021-04-08

Applicant: NIPPON STEEL CORPORATION

Inventor： Yuki SUZUKI ,  Kenta UENISHI ,  Soshi FUJITA ,  Masahiro FUDA

IPC: C23C28/04 ,  C22C38/54 ,  C22C38/50 ,  C22C38/38 ,  C22C38/28 ,  C22C38/24 ,  C22C38/32 ,  C22C38/16 ,  C22C38/14 ,  C22C38/12 ,  C22C38/06 ,  C22C38/04 ,  C22C38/02 ,  C22C38/00

CPC classification number: C23C28/042 ,  C22C38/54 ,  C22C38/50 ,  C22C38/38 ,  C22C38/28 ,  C22C38/24 ,  C22C38/32 ,  C22C38/16 ,  C22C38/14 ,  C22C38/12 ,  C22C38/06 ,  C22C38/04 ,  C22C38/02 ,  C22C38/008 ,  C22C38/002 ,  C22C38/005 ,  C22C38/001

Abstract: To provide a steel sheet for hot stamping suitable for manufacturing, through hot-stamping working, a component having portions with different strengths, and a hot-stamped member having portions with different strengths. A steel sheet for hot stamping according to the present invention includes, on a surface of the steel sheet: a site having a surface-treated film whose emissivity at a wavelength of 8.0 μm at 25° C. is 60% or more; and a site at which the surface-treated film is not provided, in which the surface-treated film contains carbon black, and one or more of oxides selected from a group consisting of a Zr oxide, a Zn oxide, and a Ti oxide, in which the carbon black and the oxides exist while being dispersed over the entire surface-treated film, the surface-treated film has a silica content of 0 to 0.3 g/m2, and when an adhesion amount of the carbon black and an adhesion amount of the oxides are set to XCB (g/m2) and XOxide (g/m2), respectively, an equation (1) below is satisfied.

公开(公告)号：US20210095368A1

公开(公告)日：2021-04-01

申请号：US16634346

申请日：2019-02-15

Applicant: NIPPON STEEL CORPORATION

Inventor： Soshi FUJITA ,  Yuki SUZUKI ,  Masahiro FUDA ,  Jun MAKI ,  Hideaki IRIKAWA ,  Tatsuya KUBOTA

IPC: C23C2/12 ,  C22C21/02 ,  C23C2/28 ,  C23C2/40 ,  C23C28/02 ,  C21D8/02 ,  C22C38/00 ,  C22C38/02 ,  C22C38/04 ,  C22C38/06 ,  C22C38/42 ,  C22C38/24 ,  C22C38/26 ,  C22C38/28 ,  C22C38/30 ,  C22C38/32 ,  C22C38/60 ,  B21D22/02

Abstract: Fe-Al-based plated hot-stamped member exhibiting excellent formed part corrosion resistance and post-coating corrosion resistance and manufacturing method. The hot-stamping member includes Fe-Al-based plated layer on one or both surfaces of a base material, the base material has a predetermined steel component, Fe-Al-based plated layer has a thickness of 10 μm or more and 60 μm or less, formed by A, B, C and D layers sequentially from a surface toward the base material, and each of the four layers is a Fe-Al-based intermetallic compound containing Al, Fe, Si, Mn and Cr for predetermined contents with the balance made up of impurities, the D layer further contains Kirkendall voids each of which cross-sectional area is 3 μm2-30 μm2 for 10 pieces/6000 μm2 or more and 40 pieces/6000 μm2 or less.

公开(公告)号：US20230166314A1

公开(公告)日：2023-06-01

申请号：US17918265

申请日：2021-04-20

Applicant: NIPPON STEEL CORPORATION

Inventor： Soshi FUJITA ,  Yuki SUZUKI ,  Masahiro FUDA ,  Hideaki IRIKAWA ,  Masahiro KUBO ,  Naruhiko NOMURA

IPC: B21D22/20 ,  B21D53/88 ,  C21D9/46

CPC classification number: B21D22/208 ,  B21D53/88 ,  C21D9/46 ,  C23C2/12

Abstract: This manufacturing method of a hot press-formed article includes a heating step of heating an Al-plated steel sheet and a forming step of obtaining a hot press-formed article using a die after the heating step, the Al-plated steel sheet has a base steel sheet, an Al plating layer, and a coating layer, the coating layer is a metal layer containing at least one metal of Mg, Ca, V, Ti, and Zn, a metal oxide layer containing an oxide of one or more of Mg, Ca, V, Ti, and Zn, or a mixed layer including the metal layer and the metal oxide layer, the die has a hard layer on a surface, HVDie that is a surface hardness of the die at a position of the hard layer is HV1500 or more and HV3800 or less, and a temperature Tm of the Al-plated steel sheet at a start of forming and an average movement velocity V of the die in the forming step satisfy 800−(HVDie/40)≤Tm≤850−(V/4)−(HVDie/100).

公开(公告)号：US20220402015A1

公开(公告)日：2022-12-22

申请号：US17789436

申请日：2021-02-24

Applicant: NIPPON STEEL CORPORATION

Inventor： Soshi FUJITA ,  Yuki SUZUKI ,  Masahiro FUDA ,  Hideaki IRIKAWA ,  Jun MAKI ,  Nobuo YOSHIKAWA ,  Naruhiko NOMURA

IPC: B21D39/03 ,  C22C38/04 ,  C22C38/02 ,  C22C38/00 ,  C23C2/12 ,  B21D22/02

Abstract: To solve a problem about warpage of a steel sheet due to a difference in temperature raising rate between an overlapped part and a one-sheet part. This manufacturing method includes: a step of heating an overlapped blank; a step of transferring the heated overlapped blank; and a step of performing presswork on the heated overlapped blank by using a die, in which in the heating step, when sheet thicknesses of the first and second steel sheets are set to t1 and t2, respectively, and an average heating rate at a sheet temperature from 20 to 800° C. of a portion with a total sheet thickness (t1+t2) of an overlapped portion, and that of a non-overlapped portion are set to V and v1, respectively, the total sheet thickness (t1+t2) is 2.5 to 5.0 mm, a maximum length L of the overlapped portion is 100 to 1100 mm, an area S1 of the first steel sheet, an area S2 of a portion, of the second steel sheet, which is overlapped with the first steel sheet, and the average heating rates V and v1 satisfy Expressions (1) to (3), and the heating is performed at a heating temperature and for a heating time within a specific range on a plane of coordinates defined by the heating time and the heating temperature.

公开(公告)号：US20210222804A1

公开(公告)日：2021-07-22

申请号：US17053662

申请日：2019-05-15

Applicant: NIPPON STEEL CORPORATION

Inventor： Hiroki FUJIMOTO ,  Masanori YASUYAMA ,  Yujiro TATSUMI ,  Hiroshi FUKUCHI ,  Shintaro KOBAYASHI ,  Soshi FUJITA ,  Tasuku ZENIYA ,  Yuki SUZUKI ,  Yoshinari ISHIDA

IPC: F16L9/17 ,  B21D22/02 ,  C22C38/38 ,  C22C38/32 ,  C22C38/28 ,  C22C38/06 ,  C22C38/02 ,  C22C38/00 ,  B32B15/01 ,  C23C2/12 ,  C23C2/26 ,  C23C2/40 ,  F16L9/02 ,  F16L9/16 ,  B23K31/02

Abstract: This steel sheet includes a first coated portion in which an intermetallic compound layer and an aluminum coating layer are provided on a surface of a base steel sheet in order from the base steel sheet side, a first exposed portion in which the base steel sheet is exposed, and a second coated portion in which the intermetallic compound layer and the aluminum coating layer are provided on the surface of the base steel sheet in order from the base steel sheet side, in which in a first direction which is perpendicular to a thickness direction of the steel sheet and is directed from the first coated portion to one end edge of the steel sheet, the first coated portion, the first exposed portion, the second coated portion, and the end edge of the steel sheet are disposed in this order on one surface of the base steel sheet, at least the first coated portion, the first exposed portion, and the end edge of the steel sheet are disposed in this order on the other surface of the base steel sheet in the first direction, and when viewing a cross section parallel to each of the first direction and the thickness direction of the steel sheet, the second coated portion is provided in a lower region which is located on the surface of the base steel sheet and on an inner side of the base steel sheet in the thickness direction of the steel sheet from a virtual line extending in the first direction from a boundary between the first exposed portion and the second coated portion.

公开(公告)号：US20210197525A1

公开(公告)日：2021-07-01

申请号：US16613981

申请日：2019-04-05

Applicant: NIPPON STEEL CORPORATION

Inventor： Soshi FUJITA ,  Yuki SUZUKI ,  Masahiro FUDA ,  Jun MAKI ,  Hideaki IRIKAWA ,  Masahiro NAKATA

IPC: B32B15/01 ,  C23C2/12 ,  B21D22/02 ,  B23K31/02

Abstract: To solve the problem about the difference in temperature increasing rate between an overlapped part and a one-sheet part so as to further improve the corrosion resistance of plating after hot stamping. An overlapped blank for hot stamping includes: a first steel sheet; and at least one second steel sheet connected to a surface of the first steel sheet via a welding point and smaller in area than the first steel sheet, wherein: the first steel sheet is a plated steel sheet having an aluminum-based plated layer on both faces of the first steel sheet, and the second steel sheet is a plated steel sheet having an aluminum-based plated layer on both faces of the second steel sheet; a coating weight of the aluminum-based plated layer on the first steel sheet is W1 (g/m2) in terms of an average coating weight on both the faces; a coating weight of the aluminum-based plated layer on a surface on a side not in contact with the first steel sheet in the second steel sheet is W2 (g/m2); and each of the W1 and the W2 is within a range of 20 g/m2 or more and 120 g/m2 or less, and satisfies relationships of Expression (1) and Expression (2).

公开(公告)号：US20210164080A1

公开(公告)日：2021-06-03

申请号：US16768869

申请日：2018-12-05

Applicant: NIPPON STEEL CORPORATION

Inventor： Soshi FUJITA ,  Yuki SUZUKI ,  Masahiro FUDA ,  Jun MAKI ,  Hideaki IRIKAWA ,  Takashi ARAMAKI ,  Tatsuya KUBOTA

IPC: C22C38/54 ,  C23C2/12 ,  C22C38/50 ,  C22C38/48 ,  C22C38/44 ,  C22C38/00 ,  C22C38/02 ,  C22C38/04 ,  C22C38/06 ,  C23C2/40 ,  C21D9/46 ,  C21D8/02 ,  C21D9/00

Abstract: An aluminum-based plated steel sheet according to an aspect of the present invention includes: a base material; an aluminum-based plating layer located above the base material; and an intermetallic compound layer that is located between the base material and the aluminum-based plating layer and contains an intermetallic compound of Al and Fe, in which the base material has a chemical component within a predetermined range, the aluminum-based plating layer contains, on average, 80 mass % or more and 97 mass % or less of Al, 3 mass % or more and 15 mass % or less of Si, 0 mass % or more and 5 mass % or less of Zn, 0 mass % or more and 5 mass % or less of Fe, 0 mass % or more and 3 mass % or less in total of one or more selected from the group consisting of Mg and Ca, and impurities so that a total amount thereof is 100 mass %, an average value of a thickness of the intermetallic compound layer is 2 μm or more and 10 μm or less, a maximum value of the thickness of the intermetallic compound layer is 10 μm or more and 25 μm or less, and a standard deviation of the thickness of the intermetallic compound layer is 2 μm or more and 10 μm or less.

公开(公告)号：US20210114074A1

公开(公告)日：2021-04-22

申请号：US17044194

申请日：2019-04-09

Applicant: NIPPON STEEL CORPORATION

Inventor： Masahiro KUBO ,  Soshi FUJITA ,  Yoshiaki NAKAZAWA ,  Hideaki IRIKAWA ,  Masahiro FUDA

IPC: B21D22/02 ,  C21D1/673 ,  B32B15/01

Abstract: A method of producing a hot press-formed product includes subjecting an Al-plated steel sheet having a zinc compound layer or a metallic zinc layer, as an outermost layer, provided on an Al plating layer to hot press forming using a die. The die includes a hard layer having a skewness (Rsk), as measured in a direction from the outside of a die hole toward the inside of the die hole, of 1.3 or less and a hardness Hv_Die of HV 2,000 or more, over the entirety of a region of a steel sheet contact surface that is adjacent to a die shoulder portion. The steel sheet contact surface is a surface located outside of the die hole and configured to contact the Al-plated steel sheet that is to be subjected to the hot press forming.