公开(公告)号：US20240247357A1

公开(公告)日：2024-07-25

申请号：US18290088

申请日：2021-05-10

Applicant: NIPPON STEEL CORPORATION

Inventor： Jun MAKI ,  Keitaro MATSUDA ,  Hiroyuki KAWATA

IPC: C23C2/40 ,  C21D6/00 ,  C21D8/02 ,  C21D9/46 ,  C22C38/00 ,  C22C38/02 ,  C22C38/04 ,  C22C38/06 ,  C22C38/08 ,  C22C38/12 ,  C22C38/14 ,  C22C38/16 ,  C22C38/22 ,  C22C38/38 ,  C23C2/06

CPC classification number: C23C2/40 ,  C21D6/001 ,  C21D6/002 ,  C21D6/005 ,  C21D6/008 ,  C21D8/0205 ,  C21D8/0226 ,  C21D8/0236 ,  C21D8/0263 ,  C21D8/0278 ,  C21D9/46 ,  C22C38/001 ,  C22C38/002 ,  C22C38/005 ,  C22C38/02 ,  C22C38/04 ,  C22C38/06 ,  C22C38/08 ,  C22C38/12 ,  C22C38/14 ,  C22C38/16 ,  C22C38/22 ,  C22C38/38 ,  C23C2/06

Abstract: The present invention relates to a galvanized steel sheet comprising steel sheet containing C: 0.05 to 0.30%, Si: 0.01 to 3.00%, Mn: 0.80 to 3.00%, and Al: 0.010 to 2.000% and having a thickness of 0.10 to 0.95 mm, and a galvanized layer on the steel sheet, wherein a tensile strength is 550 to 1500 MPa, and, when defining a thickness of an internal oxide layer per surface of the steel sheet as “A” (μm), a thickness of a decarburized layer per surface of the steel sheet as “B” (μm), and a thickness of the steel sheet as “t” (μm), A/B: 0.01 to 0.50 and B/t: 0.001 to 0.200.

公开(公告)号：US20240227354A1

公开(公告)日：2024-07-11

申请号：US18288208

申请日：2021-04-27

Applicant: NIPPON STEEL CORPORATION

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

IPC: B32B15/01 ,  B32B7/14 ,  B32B37/00 ,  C22C38/02 ,  C22C38/06

CPC classification number: B32B15/011 ,  B32B7/14 ,  B32B37/0084 ,  C22C38/02 ,  C22C38/06 ,  B32B2255/06 ,  B32B2255/205

Abstract: A steel welded member comprising a plurality of Zn-based plated steel materials, each having a Zn-based plating layer on a surface of a steel material, joined together through at least one spot weld, wherein the steel material contains, by mass %, C: 0.05 to 0.40%, Si: 0.2 to 3.0%, and Mn: 0.1 to 5.0%, the steel welded member includes, by area ratio, 20 to 80% of a Γ phase (Fe3 Zn1 0) and at least one oxide with a long axis of 0.5 μm or more in a region up to 0.5 mm from an end part of a pressure weld of the spot weld.

公开(公告)号：US20240359252A1

公开(公告)日：2024-10-31

申请号：US18579759

申请日：2022-09-30

Applicant: NIPPON STEEL CORPORATION

Inventor： Takuya MITSUNOBU ,  Hiroshi TAKEBAYASHI ,  Keitaro MATSUDA

IPC: B23K11/11 ,  B23K11/16 ,  B23K103/04 ,  C21D9/46 ,  C22C38/00 ,  C22C38/02 ,  C22C38/04 ,  C22C38/06 ,  C23C2/06 ,  C23C2/40

CPC classification number: B23K11/11 ,  B23K11/166 ,  C21D9/46 ,  C22C38/001 ,  C22C38/002 ,  C22C38/02 ,  C22C38/04 ,  C22C38/06 ,  C23C2/06 ,  C23C2/40 ,  B23K2103/04

Abstract: A steel welded member having a high LME resistance of a spot weld, i.e., a steel welded member comprised of a plurality of Zn-based plated steel materials, each comprised of a steel material and a Zn-based plating layer on its surface, joined by at least one spot weld, in which
at least one of the Zn-based plated steel materials has a 780 MPa or more tensile strength, that steel material has a chemical composition containing, by mass %,
C: 0.05 to 0.40%,
Si: 0.2 to 3.0%,
Mn: 0.1 to 5.0%,
sol. Al: 0.4 to 1.50%, etc. and having a balance of Fe and impurities, and,
in a region of 10 to 300 μm from an end of a pressure weld of the spot weld, a difference of a Zn penetration depth of Zn from a Zn-based plating layer penetrating a steel material minus a depth of an internal oxidation layer formed at the steel material is within 0.1 to 10.0 μm in range.

公开(公告)号：US20240117476A1

公开(公告)日：2024-04-11

申请号：US18274970

申请日：2022-03-14

Applicant: NIPPON STEEL CORPORATION

Inventor： Masaaki URANAKA ,  Takuya MITSUNOBU ,  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 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, 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：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：US20250051895A1

公开(公告)日：2025-02-13

申请号：US18717967

申请日：2022-12-09

Applicant: NIPPON STEEL CORPORATION

Inventor： Keitaro MATSUDA ,  Hiroshi TAKEBAYASHI

IPC: C22C38/58 ,  B32B15/01 ,  C22C38/00 ,  C22C38/02 ,  C22C38/04 ,  C22C38/06 ,  C22C38/08 ,  C22C38/12 ,  C22C38/14 ,  C22C38/16

Abstract: Steel sheet and plated steel sheet comprised of steel sheet with a thin thickness in which sufficient strength and plateability or chemical convertibility are both achieved, i.e., steel sheet having a chemical composition containing, by mass %, C: 0.05 to 0.30%, Si: 0.01 to 2.50%, Mn: 0.80 to 3.00%, Al: 0.010 to 2.000%, etc. and having a balance comprising Fe and impurities and having a thickness of 0.4 to 2.0 mm, in which steel sheet, a tensile strength is 550 to 1500 MPa, an internal oxidation layer and decarburized layer are contained, when a thickness of the decarburized layer per side of the steel sheet: A (μm), a bulk C concentration of the steel sheet: Cb (%), and a thickness of the steel sheet: t (mm), 0.01≤A/t≤0.15, and a C concentration at the ½A position is Cb/2 or more and plated steel sheet using that steel sheet.

公开(公告)号：US20240318288A1

公开(公告)日：2024-09-26

申请号：US18579732

申请日：2022-09-30

Applicant: NIPPON STEEL CORPORATION

Inventor： Takuya MITSUNOBU ,  Keitaro MATSUDA ,  Hiroshi TAKEBAYASHI

IPC: C22C38/38 ,  B32B15/01 ,  C22C38/00 ,  C22C38/02 ,  C22C38/04 ,  C22C38/06 ,  C22C38/08 ,  C22C38/12 ,  C22C38/14 ,  C22C38/16 ,  C22C38/32 ,  C22C38/34

CPC classification number: C22C38/38 ,  B32B15/013 ,  C22C38/001 ,  C22C38/002 ,  C22C38/005 ,  C22C38/02 ,  C22C38/04 ,  C22C38/06 ,  C22C38/08 ,  C22C38/12 ,  C22C38/14 ,  C22C38/16 ,  C22C38/32 ,  C22C38/34

Abstract: High strength plated steel sheet excellent in LME resistance, that is, plated steel sheet comprising steel sheet and a plating layer containing Zn on the same, in which the steel sheet has a tensile strength of 780 MPa or more, the steel sheet has a chemical composition containing, by mass %,



C: 0.05 to 0.40%,
Si: 0.2 to 3.0%,
Mn: 0.1 to 5.0%,
sol. Al: 0.4 to 1.50%, etc. and having a balance of Fe and impurities, and,

in any vertical cross section of the steel sheet, ferrite phases with a circle equivalent diameter of 1 μm or less are contained in a region from a surface layer down to a depth of 2 μm in a number density of 2 to 30/μm2 and the ferrite phases include internal oxides with a circle equivalent diameter of 2 to 100 nm in a number density of 3/μm2 or more.

公开(公告)号：US20240218491A1

公开(公告)日：2024-07-04

申请号：US18288223

申请日：2021-04-27

Applicant: NIPPON STEEL CORPORATION

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

IPC: C22C38/38 ,  C21D1/74 ,  C21D6/00 ,  C21D8/02 ,  C21D9/46 ,  C22C38/00 ,  C22C38/02 ,  C22C38/04 ,  C22C38/06 ,  C22C38/08 ,  C22C38/12 ,  C22C38/14 ,  C22C38/16 ,  C22C38/34 ,  C23C2/06

CPC classification number: C22C38/38 ,  C21D1/74 ,  C21D6/001 ,  C21D6/002 ,  C21D6/005 ,  C21D6/008 ,  C21D8/0205 ,  C21D8/0226 ,  C21D8/0236 ,  C21D8/0252 ,  C21D8/0263 ,  C21D8/0278 ,  C21D9/46 ,  C22C38/001 ,  C22C38/002 ,  C22C38/005 ,  C22C38/02 ,  C22C38/04 ,  C22C38/06 ,  C22C38/08 ,  C22C38/12 ,  C22C38/14 ,  C22C38/16 ,  C22C38/34 ,  C23C2/06

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 grain boundary oxides, a Ratio A of a length of the grain boundary oxides projected on a surface of the steel sheet to a length of the surface of the steel sheet is 50% or more and 100% or less, a number density of granular oxides is less than 4.0/μm2, 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 at the ½ position of the thickness and not containing oxides are respectively less than 10% of the Si and Mn contents at a sheet thickness center part of the steel sheet, and a plated steel sheet using the same are provided.