公开(公告)号：US20250035139A1

公开(公告)日：2025-01-30

申请号：US18716435

申请日：2023-01-26

Applicant: NIPPON STEEL CORPORATION

Inventor： Masaaki URANAKA ,  Takuya MITSUNOBU ,  Masahiro MATSUBA ,  Toyomitsu NAKAMURA

IPC: F16B5/08

Abstract: To further improve corrosion resistance in the vicinity of a toe.
A welded joint according to the present invention includes: a first steel sheet and a second steel sheet; and a weld bead zone formed by arc welding or laser welding, wherein at least one of the first steel sheet or the second steel sheet has a plating layer formed by a predetermined component and an oxide layer located on the plating layer in a non-heat-affected zone, and in a region from a position orthogonal to an extension direction of the weld bead zone from the toe and 1 mm in a direction separating from the toe to a position orthogonal to the extension direction from the toe and 2 mm in the direction separating from the toe, the plating layer has at least one of a η-Zn phase, MgZn2 phase, Mg2Zn3 phase, or MgZn phase as a metal Zn-containing phase having a circle-equivalent diameter of 0.5 μm or more, and when each of the metal Zn-containing phases is projected onto an interface between a base iron and the plating layer, a total sum of lengths of the metal Zn-containing phases in the direction orthogonal to the extension direction, Lt, is 10% or more of a length of the interface, Le.

公开(公告)号：US20250003048A1

公开(公告)日：2025-01-02

申请号：US18711221

申请日：2023-01-26

Applicant: NIPPON STEEL CORPORATION

Inventor： Takuya MITSUNOBU ,  Masaaki URANAKA ,  Masahiro MATSUBA ,  Toyomitsu NAKAMURA

IPC: C23C2/40 ,  B32B15/01 ,  C22C18/00 ,  C22C18/04 ,  C22C21/02 ,  C22C21/08 ,  C22C21/10 ,  C22C30/06 ,  C22C38/02 ,  C22C38/04 ,  C23C2/02 ,  C23C2/04 ,  C23C2/06 ,  C23C2/12 ,  C23C2/20

Abstract: To more reliably suppress LME and blowhole formation while maintaining excellent corrosion resistance.
A plated steel sheet according to the present invention, includes: a steel sheet as a base material; a plating layer located on at least part of a surface of the steel sheet; and an oxide layer located on a surface of the plating layer, where a chemical composition of the plating layer is made up of prescribed components, and Zn and impurities as the balance, and when a position at a depth of 5 nm from an uppermost surface of the oxide layer is observed by X-ray photoelectron spectroscopy (XPS), a value of an intensity ratio ([Al—O]+[Mg—O])/[Zn—O]) calculated from intensity of peaks respectively attributed to an Al—O bond, an Mg—O bond, and a Zn—O bond is 5.0 or more.

公开(公告)号：US20250065450A1

公开(公告)日：2025-02-27

申请号：US18725477

申请日：2023-01-26

Applicant: NIPPON STEEL CORPORATION

Inventor： Masahiro MATSUBA ,  Takuya MITSUNOBU ,  Masaaki URANAKA ,  Toyomitsu NAKAMURA

IPC: B23K35/30 ,  B23K9/23 ,  B23K26/322 ,  B23K35/28 ,  B23K103/04 ,  B23K103/16

Abstract: To further improve electrodeposition coating properties in a weld bead zone.
A welded joint according to the present invention includes: a first steel sheet and a second steel sheet; and a weld bead zone formed by arc welding or laser welding, wherein at least one of the first steel sheet or the second steel sheet has a plating layer composed of a predetermined component and an oxide layer located on the plating layer in a non-heat-affected zone, and the weld bead zone has a weld metal and a slag layer formed on part of a surface of the weld metal, and the slag layer contains, by mass % when oxygen is excluded, Al: 1.0 to 45.0% and Mg: 1.0 to 30.0%, with the balance composed of Fe, easily oxidizable metallic elements, and impurities.

公开(公告)号：US20230416888A1

公开(公告)日：2023-12-28

申请号：US18463110

申请日：2023-09-07

Applicant: NIPPON STEEL CORPORATION

Inventor： Jun MAKI ,  Soshi FUJITA ,  Toyomitsu NAKAMURA

IPC: C22C38/54 ,  B23K11/00 ,  B23K35/02 ,  B23K35/30 ,  C21D9/08 ,  C22C38/00 ,  C22C38/02 ,  C22C38/06 ,  C22C38/42 ,  C22C38/44 ,  C22C38/48 ,  C22C38/50 ,  C25D3/44 ,  C25D7/04

CPC classification number: C22C38/54 ,  B23K11/002 ,  B23K35/0261 ,  B23K35/3053 ,  C21D9/08 ,  C22C38/001 ,  C22C38/002 ,  C22C38/02 ,  C22C38/06 ,  C22C38/42 ,  C22C38/44 ,  C22C38/48 ,  C22C38/50 ,  C25D3/44 ,  C25D7/04 ,  B23K2103/04

Abstract: An Al plated electric resistance welded steel pipe for hardening use suppressing the formation of scale to the inside of the plating layer while performing hot forming and an Al plated hollow member using that Al plated electric resistance welded steel pipe, wherein the Al plated electric resistance welded steel pipe for hardening use is comprised of a base material made of a tubular steel plate and having a predetermined chemical composition and an electric resistance welded zone provided at a seam portion of the steel plate and extending in a longitudinal direction of the steel plate, the base material is further provided with an intermetallic compound layer positioned on the surface of the steel plate and including an Al—Fe—Si-based intermetallic compound and an Al plating layer positioned on the surface of the intermetallic compound layer and containing Al and Si, and 70×X/D≤Y/t≤30 is satisfied, wherein X (μm) is a thickness of the intermetallic compound layer, Y (μm) is a thickness of the Al plating layer, t (mm) is a pipe thickness of the steel pipe, and D (mm) is an outside diameter of the steel pipe.

公开(公告)号：US20220177994A1

公开(公告)日：2022-06-09

申请号：US17599443

申请日：2019-11-15

Applicant: NIPPON STEEL CORPORATION

Inventor： Kengo TAKEDA ,  Yuya SUZUKI ,  Toyomitsu NAKAMURA ,  Seiji FURUSAKO

IPC: C21D9/46 ,  B32B15/01 ,  C22C38/54 ,  C22C38/52 ,  C22C38/50 ,  C22C38/58 ,  C22C38/48 ,  C22C38/44 ,  C22C38/06 ,  C22C38/02 ,  C22C38/00 ,  B22D11/11 ,  C21D8/02 ,  C21D6/00

Abstract: Provided is a steel sheet having a predetermined chemical composition and structure wherein (Fe, Mn)2 B precipitates having a circle equivalent diameter of 50 to 300 nm are present in a number density of 1/500 μm2 or more in a surface layer region down to a depth of 100 μm from the surface in the sheet thickness direction. Further, provided is a method for producing a steel sheet comprising continuously casting a molten steel having a predetermined chemical composition to form a steel slab, wherein the continuously casting includes introducing more than 10 ppm and less than 100 ppm of oxygen into the surface layer of the steel slab, hot rolling including finish rolling the steel slab, wherein a completion temperature of the finish rolling is 650 to 950° C., coiling the obtained hot rolled steel sheet at a coiling temperature of 400 to 700° C., and cold rolling the hot rolled steel sheet, then annealing it.

公开(公告)号：US20200347489A1

公开(公告)日：2020-11-05

申请号：US16753961

申请日：2017-11-20

Applicant: NIPPON STEEL CORPORATION

Inventor： Jun MAKI ,  Soshi FUJITA ,  Toyomitsu NAKAMURA

IPC: C22C38/54 ,  C22C38/42 ,  C22C38/44 ,  C22C38/48 ,  C22C38/50 ,  C22C38/02 ,  C22C38/06 ,  C22C38/00 ,  C21D9/08 ,  B23K35/30 ,  B23K35/02 ,  C25D3/44 ,  C25D7/04 ,  B23K11/00

Abstract: An Al plated electric resistance welded steel pipe for hardening use suppressing the formation of scale to the inside of the plating layer while performing hot forming and an Al plated hollow member using that Al plated electric resistance welded steel pipe, wherein the Al plated electric resistance welded steel pipe for hardening use is comprised of a base material made of a tubular steel plate and having a predetermined chemical composition and an electric resistance welded zone provided at a seam portion of the steel plate and extending in a longitudinal direction of the steel plate, the base material is further provided with an intermetallic compound layer positioned on the surface of the steel plate and including an Al-Fe-Si-based intermetallic compound and an Al plating layer positioned on the surface of the intermetallic compound layer and containing Al and Si, and 70×X/D≤Y/t≤30 is satisfied, wherein X (μm) is a thickness of the intermetallic compound layer, Y (μm) is a thickness of the Al plating layer, t (mm) is a pipe thickness of the steel pipe, and D (mm) is an outside diameter of the steel pipe.

公开(公告)号：US20200325554A1

公开(公告)日：2020-10-15

申请号：US16772692

申请日：2017-12-15

Applicant: NIPPON STEEL CORPORATION

Inventor： Kengo TAKEDA ,  Kunio HAYASHI ,  Akihiro UENISHI ,  Hiroyuki KAWATA ,  Chisato YOSHINAGA ,  Yasunobu MIYAZAKI ,  Toyomitsu NAKAMURA

IPC: C21D9/46 ,  B32B15/01 ,  C22C38/38 ,  C22C38/16 ,  C22C38/14 ,  C22C38/12 ,  C22C38/08 ,  C22C38/06 ,  C22C38/02 ,  C22C38/00 ,  C21D8/02 ,  C21D6/00

Abstract: A steel sheet having a chemical composition of the base metal including, in mass %, C: 0.17 to 0.40%, Si: 0.10 to 2.50%, Mn: 1.00 to 10.00%, P: 0.001 to 0.03%, S: 0.0001 to 0.02%, Al: 0.001 to 2.50%, N: 0.0001 to 0.010%, O: 0.0001 to 0.010%, Ti: 0 to 0.10%, Nb: 0 to 0.10%, V: 0 to 0.10%, B: 0 to 0.010%, Cr: 0 to 2.00%, Ni: 0 to 2.00%, Cu: 0 to 2.00%, Mo: 0 to 2.00%, Ca: 0 to 0.50%, Mg: 0 to 0.50%, REM: 0 to 0.50%, the balance: Fe and impurities, wherein the steel sheet has an internal oxidized layer in which at least one part of a crystal grain boundary is covered by oxides, and in which a grain boundary coverage ratio of oxides is 60% or more in a region from the surface of the base metal to a depth of 5.0 μm.