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：US20240240278A1

公开(公告)日：2024-07-18

申请号：US18288201

申请日：2021-04-27

Applicant: NIPPON STEEL CORPORATION

Inventor： Takuya MITSUNOBU ,  Keitaro MATSUDA ,  Jun MAKI ,  Takehiro TAKAHASHI ,  Hiroshi TAKEBAYASHI

IPC: C21D9/46 ,  C22C38/00 ,  C22C38/02 ,  C22C38/04 ,  C23C2/06 ,  C23C2/40

CPC classification number: C21D9/46 ,  C22C38/001 ,  C22C38/002 ,  C22C38/02 ,  C22C38/04 ,  C23C2/06 ,  C23C2/40

Abstract: A steel sheet comprising, by mass %, C: 0.05 to 0.40%, Si: 0.2 to 3.0%, and Mn: 0.1 to 5.0%, wherein a surface layer of the steel sheet contains granular oxides, an average grain size of the granular oxides is 300 nm or less, a number density of granular oxides is 4.0/μm2 or more, the steel sheet comprises an Si—Mn depleted layer having a thickness of 3.0 μm or more from the surface of the steel sheet, and Si and Mn contents of the Si—Mn depleted layer not containing oxides at the ½ position of the thickness are respectively less than 10% of the Si and Mn contents at the sheet thickness center part of the steel sheet, and a plated steel sheet using the same are provided.

公开(公告)号：US20240117475A1

公开(公告)日：2024-04-11

申请号：US18274960

申请日：2022-03-14

Applicant: NIPPON STEEL CORPORATION

Inventor： Takuya MITSUNOBU ,  Masaaki URANAKA ,  Keitaro MATSUDA ,  Hiroshi TAKEBAYASHI ,  Jun MAKI

IPC: C22C38/06 ,  C22C38/02 ,  C22C38/04 ,  C23C2/06

CPC classification number: C22C38/06 ,  C22C38/02 ,  C22C38/04 ,  C23C2/06

Abstract: High strength steel sheet and plated steel sheet having high plateability, LME resistance, and hydrogen embrittlement resistance, that is, steel sheet containing C: 0.05 to 0.40%, Si: 0.2 to 3.0%, Mn: 0.1 to 5.0%, and sol. Al: 0.4 to 1.50%, having an internal oxidation layer including fine granular oxides and coarse granular oxides in a surface layer of the steel sheet, a number density of fine granular oxides in the internal oxidation layer being 4.0/μm2 or more, a number density of coarse granular oxides in the internal oxidation layer being 4.0/25 μm2 or more and 30.0/25 μm2 or less, and including a surface depleted layer with a steel composition not including oxides which satisfies, by mass %, Si≤0.6% and Al≥0.05% at a depth of ½ of the average depth of the internal oxidation layer calculated from the cross-sectional SEM image of the steel sheet, and a plated steel sheet using the same.

公开(公告)号：US20230399727A1

公开(公告)日：2023-12-14

申请号：US18271138

申请日：2022-03-14

Applicant: NIPPON STEEL CORPORATION

Inventor： Keitaro MATSUDA ,  Takuya MITSUNOBU ,  Masaaki URANAKA ,  Jun MAKI ,  Hiroshi TAKEBAYASHI

IPC: C22C38/38 ,  C22C38/16 ,  C22C38/14 ,  C22C38/12 ,  C22C38/08 ,  C22C38/06 ,  C22C38/04 ,  C22C38/02 ,  C22C38/00 ,  C21D9/46 ,  C21D8/02 ,  C21D6/00 ,  C21D1/84 ,  C23C2/06 ,  C23C2/40

CPC classification number: C22C38/38 ,  C22C38/16 ,  C22C38/14 ,  C22C38/12 ,  C22C38/08 ,  C22C38/06 ,  C22C38/04 ,  C22C38/02 ,  C22C38/005 ,  C22C38/002 ,  C22C38/001 ,  C21D9/46 ,  C21D8/0278 ,  C21D8/0263 ,  C21D8/0226 ,  C21D8/0236 ,  C21D8/0205 ,  C21D6/001 ,  C21D6/002 ,  C21D6/005 ,  C21D6/008 ,  C21D1/84 ,  C23C2/06 ,  C23C2/40

Abstract: High strength steel sheet and plated steel sheet having high plateability, LME resistance, and hydrogen embrittlement resistance, that is, steel sheet containing C: 0.05 to 0.40%, Si: 0.2 to 3.0%, Mn: 0.1 to 5.0%, and sol. Al: 0.4 to 1.50%, having an internal oxidation layer including fine granular oxides, coarse granular oxides, and grain boundary oxides in a surface layer of the steel sheet, a number density of fine granular oxides in the internal oxidation layer being 4.0/μm2 or more, a number density of coarse granular oxides in the internal oxidation layer being 4.0/25 μm2 or more, having a Ratio A of the length of the grain boundary oxides projected on the surface of the steel sheet to the length of the surface of the steel sheet when examining a cross-section of the surface layer of the steel sheet being 50% or more and 100% or less, and including a surface depleted layer with a steel composition not including oxides which satisfies, by mass %, Si≤0.6% and Al≥0.05% at a depth of ½ of the average depth of the internal oxidation layer calculated from the cross-sectional SEM image of the steel sheet, and a plated steel sheet using the same.

公开(公告)号：US20230147056A1

公开(公告)日：2023-05-11

申请号：US17802583

申请日：2020-02-27

Applicant: NIPPON STEEL CORPORATION

Inventor： Takuya MITSUNOBU ,  Takehiro TAKAHASHI ,  Jun MAKI

IPC: C22C30/06 ,  B32B15/01 ,  C23C2/06

CPC classification number: C22C30/06 ,  B32B15/013 ,  C23C2/06

Abstract: A hot stamped body comprising a steel base material and an Al-Zn-Mg-based plating layer formed on a surface of the steel base material, wherein the plating layer has a predetermined chemical composition, the plating layer comprises an interfacial layer positioned at an interface with the steel base material and containing Fe and Al and a main layer positioned on the interfacial layer, the main layer comprises, by area ratio, 10.0 to 85.0% of an Mg—Zn containing phase and 15.0 to 90.0% of an Fe—Al containing phase, the Mg—Zn containing phase comprises at least one selected from the group consisting of an MgZn phase, Mg2 Zn3 phase, and MgZn2 phase, and the Fe—Al containing phase comprises at least one of an FeAl phase and Fe—Al—Zn phase and an area ratio of the Fe—Al—Zn phase in the main layer is 10.0% or less.

公开(公告)号：US20230121606A1

公开(公告)日：2023-04-20

申请号：US17802736

申请日：2020-02-27

Applicant: NIPPON STEEL CORPORATION

Inventor： Takuya MITSUNOBU ,  Takehiro TAKAHASHI ,  Jun MAKI

IPC: C22C38/06 ,  C23C2/28 ,  C22C38/02 ,  C22C38/00 ,  C23C2/04 ,  B21D22/02

Abstract: A hot stamped body comprising a steel base material and an Al—Zn—Mg-based plating layer formed on a surface of the steel base material, wherein the plating layer has a predetermined chemical composition, the plating layer comprises an interfacial layer positioned at an interface with the steel base material and containing Fe and Al and a main layer positioned on the interfacial layer, the main layer comprises, by area ratio, 10.0 to 70.0% of an Mg—Zn containing phase and 30.0 to 90.0% of an Fe—Al containing phase, the Mg—Zn containing phase comprises at least one selected from the group consisting of an MgZn phase, Mg2Zn3 phase, and MgZn2 phase, and the Fe—Al containing phase comprises an FeAl phase and Fe—Al—Zn phase and an area ratio of the Fe—Al—Zn phase in the main layer is more than 10.0 to 75.0%.

公开(公告)号：US20230088501A1

公开(公告)日：2023-03-23

申请号：US17802584

申请日：2020-02-27

Applicant: NIPPON STEEL CORPORATION

Inventor： Takuya MITSUNOBU ,  Takehiro TAKAHASHI ,  Jun MAKI

IPC: B21D22/02 ,  B32B15/01 ,  C22C18/04 ,  C23C2/06

Abstract: A hot stamped body comprising a steel base material and an Al—Zn—Mg-based plating layer formed on a surface of the steel base material, wherein the plating layer has a predetermined chemical composition, the plating layer comprises an interfacial layer positioned at an interface with the steel base material and containing Fe and Al and a main layer positioned on the interfacial layer, the main layer comprises, by area ratio, 10.0 to 90.0% of an Mg—Zn containing phase, 5.0 to less than 30.0% of an Fe—Al containing phase, and 2.0 to 25.0% of an Al—Si containing oxide phase, the Mg—Zn containing phase comprises at least one selected from the group consisting of an MgZn phase, Mg2 Zn3 phase, and MgZn2 phase, and the Fe—Al containing phase comprises at least one of an FeAl phase and Fe—Al—Zn phase.

公开(公告)号：US20230033301A1

公开(公告)日：2023-02-02

申请号：US17778178

申请日：2020-11-20

Applicant: NIPPON STEEL CORPORATION

Inventor： Hiroyasu FUJII ,  Jun MAKI ,  Kazutoshi TAKEDA ,  Akira AKAGI ,  Hiroyuki MIMURA

IPC: H01F1/147 ,  B05D7/14 ,  B05D3/02 ,  H01F41/02 ,  C08K3/32

Abstract: A non-oriented electrical steel sheet according to one embodiment of the present invention includes a base metal steel sheet, and a composite coating film composed of a Zn-containing phosphate and an organic resin, the composite coating film being formed on a surface of the base metal steel sheet, wherein: a content of Zn in the composite coating film is 10 mg/m2 or more per side; and the product of an amount of oxygen in the base metal steel sheet and a sheet thickness of the base metal steel sheet is 50 ppm·mm or less.

公开(公告)号：US20220145425A1

公开(公告)日：2022-05-12

申请号：US17434988

申请日：2020-04-16

Applicant: NIPPON STEEL CORPORATION

Inventor： Takuya MITSUNOBU ,  Jun MAKI ,  Hiroshi TAKEBAYASHI ,  Takehiro TAKAHASHI ,  Kohei TOKUDA

IPC: C22C18/04 ,  C23C2/06 ,  C23C2/02

Abstract: A plated steel sheet includes: a steel sheet; and a plating layer that is formed on at least a part of a surface of the steel sheet, in which a chemical composition of the plating layer includes, by mass %, Al: more than 5.00% and 35.00% or less, Mg: 3.00% to 15.00%, Si: 0% to 2.00%, Ca: 0% to 2.00%, and a remainder of Zn and impurities, in which in a cross section of the plating layer in a thickness direction, the area ratio of a lamellar structure in which an (Al—Zn) phase and a MgZn2 phase are arranged in layers is 10% to 90%, a lamellar spacing of the lamellar structure is 2.5 μm or less, and the area ratio of an (Al—Zn) dendrite is 35% or less.