公开(公告)号：US20240367254A1

公开(公告)日：2024-11-07

申请号：US18561353

申请日：2022-03-14

Applicant: JFE STEEL CORPORATION

Inventor： Katsutoshi TAKASHIMA ,  Shunsuke YAMAMOTO ,  Katsuya HOSHINO ,  Hiroshi MATSUDA

IPC: B23K11/11 ,  B23K11/16 ,  F16B5/08

Abstract: A resistance spot welded member and a resistance spot welding method. The resistance spot welded member includes a resistance spot weld formed by resistance-spot-welding a plurality of steel sheets including at least one high strength coated steel sheet. The high strength coated steel sheet has a specific chemical composition. The at least one high strength coated steel sheet includes a coated layer, a base metal, and an Fe-based electroplated base layer interposed between the coated layer and the base metal. The amount of solute Si and the amount of solute Mn in a region on a steel sheet surface in the vicinity of the edge of the corona of the resistance spot weld are 35% or less of the amount of solute Si and 35% or less of the amount of solute Mn, respectively, at a position ¼ of the sheet thickness.

公开(公告)号：US20240238891A1

公开(公告)日：2024-07-18

申请号：US18291661

申请日：2022-07-19

Applicant: JFE STEEL CORPORATION

Inventor： Nao KAWABE ,  Chikaumi SAWANISHI ,  Katsutoshi TAKASHIMA ,  Koichi TANIGUCHI ,  Hiroshi MATSUDA ,  Daiki YAMAGISHI

IPC: B23K11/11

CPC classification number: B23K11/115

Abstract: A resistance spot welding method in which a high strength zinc-based coated steel sheet used in a sheet set has an equivalent carbon content of 0.20% or more and a tensile strength of 780 MPa or more. The method includes performing a first energization step such that a current value at the end of the energization, a current value Is at the start of the energization, and a thickness of the thinnest steel sheet among steel sheets overlapping each other satisfy specified relationships. The method includes performing a second energization step in which a cooling step of holding a non-energization state for 10 ms or longer and shorter than 160 ms and performing energization at a current value equal to or more than the current value at the end of the first energization step for 20 ms or longer and shorter than 200 ms are repeated.

公开(公告)号：US20240158884A1

公开(公告)日：2024-05-16

申请号：US18550459

申请日：2022-02-28

Applicant: JFE STEEL CORPORATION

Inventor： Yoshiyasu KAWASAKI ,  Yuki TOJI ,  Tatsuya NAKAGAITO ,  Shinya YAMAGUCHI ,  Masayasu UENO ,  Katsutoshi TAKASHIMA ,  Tomohiro ONO

IPC: C21D9/46 ,  B32B15/01 ,  C21D6/00 ,  C21D8/02 ,  C22C38/00 ,  C22C38/02 ,  C22C38/04 ,  C22C38/06 ,  C22C38/08 ,  C22C38/10 ,  C22C38/12 ,  C22C38/14 ,  C22C38/16 ,  C22C38/24 ,  C22C38/38 ,  C22C38/60 ,  C23C2/06 ,  C23C2/28 ,  C25D3/22 ,  C25D5/50

CPC classification number: C21D9/46 ,  B32B15/011 ,  C21D6/001 ,  C21D6/002 ,  C21D6/005 ,  C21D6/007 ,  C21D6/008 ,  C21D8/0205 ,  C21D8/0226 ,  C21D8/0236 ,  C21D8/0257 ,  C21D8/0263 ,  C21D8/0278 ,  C22C38/001 ,  C22C38/002 ,  C22C38/004 ,  C22C38/005 ,  C22C38/02 ,  C22C38/04 ,  C22C38/06 ,  C22C38/08 ,  C22C38/10 ,  C22C38/12 ,  C22C38/14 ,  C22C38/16 ,  C22C38/24 ,  C22C38/38 ,  C22C38/60 ,  C23C2/06 ,  C23C2/285 ,  C25D3/22 ,  C25D5/50

Abstract: A clad steel plate having tensile strength (TS) of 780 MPa or more, excellent ductility, bendability, collision resistance, and LME resistance. The clad steel plate having a base metal and a cladding metal on front and back surfaces of the base metal, and the chemical composition and microstructure of the base metal and the cladding metal being appropriately controlled so that the average Vickers hardness (HVL) of the cladding metal is 260 or less, the average Vickers hardness (HVL) of the cladding metal divided by the average Vickers hardness (HVB) of the base metal is 0.80 or less, the boundary roughness between the base metal and the cladding metal is 50 μm or less at the maximum height Ry, and the number of voids at the boundary between the base metal and the cladding metal is controlled to 20 or fewer per 10 mm length of the boundary.

公开(公告)号：US20190161822A1

公开(公告)日：2019-05-30

申请号：US16320864

申请日：2017-08-10

Applicant: JFE STEEL CORPORATION

Inventor： Katsutoshi TAKASHIMA ,  Koichi TANIGUCHI ,  Takashi KOBAYASHI ,  Hiroshi MATSUDA ,  Rinsei IKEDA

IPC: C21D9/46 ,  C21D8/02 ,  C22C38/38 ,  C22C38/12 ,  C22C38/08 ,  C22C38/22 ,  C22C38/00 ,  C22C38/26 ,  C22C38/24 ,  C22C38/28 ,  C22C38/14 ,  C22C38/32 ,  C22C38/06 ,  C22C38/04 ,  C22C38/02 ,  C23C2/02 ,  C23C2/06 ,  C23C2/28

Abstract: A high-strength steel sheet having a specified chemical composition and a method for producing the same. The steel sheet including a multi-phase structure including, by volume fraction, ferrite of 35% to 65%, residual austenite of 7% or less (including 0%), martensite of 20% to 60%, bainite of 20% or less (including 0%), the ferrite having an average crystal grain size of 8 μm or less and an average aspect ratio of 3.5 or less, the martensite having an average crystal grain size of 3 μm or less, and the bainite having an average crystal grain size of 3 μm or less when contained. A standard deviation of Vickers hardness of the steel sheet being 30 or less when measured at 200 μm intervals from a position of 100 μm from a surface to a central portion in a thickness direction of the sheet.

公开(公告)号：US20170022582A1

公开(公告)日：2017-01-26

申请号：US15301097

申请日：2015-03-17

Applicant: JFE STEEL CORPORATION

Inventor： Katsutoshi TAKASHIMA ,  Kohei HASEGAWA

IPC: C21D9/46 ,  C22C38/34 ,  C22C38/32 ,  C22C38/28 ,  C22C38/16 ,  C22C38/14 ,  C22C38/12 ,  C22C38/08 ,  C22C38/06 ,  C22C38/04 ,  C22C38/02 ,  C22C38/00 ,  C21D8/02 ,  B22D11/00 ,  C22C38/38

CPC classification number: C21D9/46 ,  B22D11/001 ,  C21D1/25 ,  C21D8/021 ,  C21D8/0226 ,  C21D8/0263 ,  C21D8/0273 ,  C21D8/0473 ,  C21D2211/001 ,  C21D2211/005 ,  C21D2211/008 ,  C22C38/00 ,  C22C38/001 ,  C22C38/002 ,  C22C38/005 ,  C22C38/02 ,  C22C38/04 ,  C22C38/06 ,  C22C38/08 ,  C22C38/12 ,  C22C38/14 ,  C22C38/16 ,  C22C38/28 ,  C22C38/32 ,  C22C38/34 ,  C22C38/38 ,  C22C38/58

Abstract: A high-strength cold-rolled steel sheet having good ductility, hole expandability, and delayed fracture resistance and being excellent in material homogeneity. The steel sheet has a chemical composition containing, in mass %, C: 0.15 to 0.25%, Si: 1.2 to 2.2%, Mn: 1.7 to 2.5%, P: 0.05% or less, S: 0.005% or less, Al: 0.01 to 0.10%, N: 0.006% or less, Ti: 0.003 to 0.030%, B: 0.0002 to 0.0050%, and Fe and inevitable impurities. The steel sheet has a microstructure that includes ferrite having an average crystal grain diameter of 4 μm or less at a volume fraction of 5 to 20%, retained austenite at a volume fraction of 5% or less, including 0%, and tempered martensite at a volume fraction of 80 to 95%. Additionally, the mean free path of the ferrite is 3.0 to 7.5 μm.

Abstract translation: 具有良好的延展性，扩孔性和延迟抗断裂性，材料均匀性优异的高强度冷轧钢板。 该钢板具有以质量％计含有C：0.15〜0.25％，Si：1.2〜2.2％，Mn：1.7〜2.5％，P：0.05％以下，S：0.005％以下的化学成分，Al： 0.01〜0.10％，N：0.006％以下，Ti：0.003〜0.030％，B：0.0002〜0.0050％，Fe及不可避免的杂质。 该钢板具有包含体积分数为5〜20％的平均结晶粒径为4μm以下的铁素体的微观结构，体积分数为5％以下的残留奥氏体为0％，回火马氏体为 体积分数为80〜95％。 此外，铁素体的平均自由程为3.0〜7.5μm。

公开(公告)号：US20250102009A1

公开(公告)日：2025-03-27

申请号：US18728240

申请日：2022-11-25

Applicant: JFE STEEL CORPORATION

Inventor： Katsutoshi TAKASHIMA ,  Shunsuke YAMAMOTO ,  Tomomi KANAZAWA ,  Katsuya HOSHINO ,  Hiroshi MATSUDA

IPC: F16B37/06 ,  B23K11/00 ,  B23K11/14 ,  B23K11/16 ,  B23K103/04 ,  C22C38/02 ,  C22C38/04 ,  C22C38/06 ,  C23C2/06 ,  C25D3/56 ,  C25D7/06

Abstract: A welded joint formed by performing projection welding on a high-strength coated steel sheet and a nut, includes a content of solid solution Mn in a first region in a surface layer of the steel sheet on an outermost periphery of a weld is 40% or less of a content of solid solution Mn in a second region in a central region in a thickness direction of the steel sheet on the outermost periphery of the weld, and a content of solid solution Mn in a third region in the surface layer of the steel sheet on an innermost periphery of the weld is 40% or less of a content of solid solution Mn in a fourth region in the central region in the thickness direction of the steel sheet on the innermost periphery of the weld.

公开(公告)号：US20240424596A1

公开(公告)日：2024-12-26

申请号：US18701761

申请日：2022-10-28

Applicant: JFE STEEL CORPORATION

Inventor： Chikaumi SAWANISHI ,  Daiki YAMAGISHI ,  Nao KAWABE ,  Koichi TANIGUCHI ,  Katsutoshi TAKASHIMA

IPC: B23K11/11 ,  F16B5/08

Abstract: A resistance spot welded member includes overlapping steel sheets resistance-spot-welded together at a spot-shaped weld called a nugget, and a Zn alloy layer formed between two of the overlapping steel sheets. At least one of the steel sheets is a galvanized steel sheet having a Zn-based coated layer on its steel sheet surface. The resistance spot welded member satisfies the following formulas (1) and (2): C Fe ≥ 20 ( 1 ) 0

公开(公告)号：US20240150876A1

公开(公告)日：2024-05-09

申请号：US18549921

申请日：2022-02-28

Applicant: JFE STEEL CORPORATION

Inventor： Yoshiyasu KAWASAKI ,  Yuki TOJI ,  Tatsuya NAKAGAITO ,  Shinya YAMAGUCHI ,  Masayasu UENO ,  Katsutoshi TAKASHIMA ,  Tomohiro ONO

IPC: C22C38/04 ,  C21D3/06 ,  C21D6/00 ,  C21D8/02 ,  C21D9/46 ,  C22C38/02 ,  C22C38/06 ,  C23C2/06 ,  C23C2/28

CPC classification number: C22C38/04 ,  C21D3/06 ,  C21D6/005 ,  C21D8/0226 ,  C21D8/0236 ,  C21D8/0273 ,  C21D9/46 ,  C22C38/02 ,  C22C38/06 ,  C23C2/06 ,  C23C2/28 ,  C21D2211/005

Abstract: A clad steel plate having tensile strength (TS) of 780 MPa or more, excellent bendability, collision resistance, and LME resistance. The clad steel plate having a base metal and a cladding metal on front and back surfaces of the base metal, and the chemical composition and microstructure of the base metal and the cladding metal being appropriately controlled so that the average Vickers hardness (HVL) of the cladding metal is 260 or less, the average Vickers hardness (HVL) of the cladding metal divided by the average Vickers hardness (HVB) of the base metal is 0.80 or less, the boundary roughness between the base metal and the cladding metal is 50 μm or less at the maximum height Ry, and the number of voids at the boundary between the base metal and the cladding metal is controlled to 20 or fewer per 10 mm length of the boundary.

公开(公告)号：US20240117517A1

公开(公告)日：2024-04-11

申请号：US18250978

申请日：2021-11-05

Applicant: JFE STEEL CORPORATION

Inventor： Shunsuke YAMAMOTO ,  Katsutoshi TAKASHIMA ,  Yusuke OKUMURA ,  Tomomi KANAZAWA ,  Katsuya HOSHINO ,  Takashi KAWANO ,  Takako YAMASHITA ,  Hiroshi MATSUDA ,  Yoichi MAKIMIZU

IPC: C25D3/20 ,  C21D8/02 ,  C21D9/46 ,  C22C38/00 ,  C22C38/02 ,  C22C38/04 ,  C22C38/06 ,  C25D7/06

CPC classification number: C25D3/20 ,  C21D8/0236 ,  C21D8/0257 ,  C21D9/46 ,  C22C38/001 ,  C22C38/002 ,  C22C38/02 ,  C22C38/04 ,  C22C38/06 ,  C25D7/0614

Abstract: Disclosed is an Fe-based electroplated steel sheet including: a Si-containing cold-rolled steel sheet containing Si in an amount of 0.1 mass % or more and 3.0 mass % or less; and an Fe-based electroplating layer formed on at least one surface of the Si-containing cold-rolled steel sheet with a coating weight per surface of 5.0 g/m2 or more, in which in an intensity profile measured by glow discharge optical emission spectrometry, a peak of emission intensity at wavelengths indicating Si is detected within a range from a surface of the Fe-based electroplating layer to more than 0.2 μm in a thickness direction and not more than a thickness of the Fe-based electroplating layer, and an average value of C concentration in a region ranging from 10 μm to 20 μm in the thickness direction from the surface of the Fe-based electroplating layer is 0.10 mass % or less.

公开(公告)号：US20230407485A1

公开(公告)日：2023-12-21

申请号：US18251269

申请日：2021-11-05

Applicant: JFE STEEL CORPORATION

Inventor： Shunsuke YAMAMOTO ,  Katsutoshi TAKASHIMA ,  Mai AOYAMA ,  Yusuke OKUMURA ,  Tomomi KANAZAWA ,  Katsuya HOSHINO ,  Hiroshi MATSUDA ,  Ei OKUMURA ,  Yoichi MAKIMIZU ,  Masaki KOBA

IPC: C23C28/02 ,  C21D9/46 ,  C22C38/38 ,  C22C38/32 ,  C22C38/28 ,  C22C38/16 ,  C22C38/14 ,  C22C38/12 ,  C22C38/08 ,  C22C38/06 ,  C22C38/04 ,  C22C38/02 ,  C22C38/00 ,  C21D6/00 ,  C22C33/04 ,  C21D8/02 ,  C21D1/74 ,  C25D3/20 ,  C25D5/36

CPC classification number: C23C28/021 ,  C21D9/46 ,  C22C38/38 ,  C22C38/32 ,  C22C38/28 ,  C22C38/16 ,  C22C38/14 ,  C22C38/12 ,  C22C38/08 ,  C22C38/06 ,  C22C38/04 ,  C22C38/02 ,  C22C38/002 ,  C22C38/001 ,  C21D6/001 ,  C21D6/002 ,  C21D6/005 ,  C21D6/008 ,  C22C33/04 ,  C21D8/0205 ,  C21D8/0226 ,  C21D8/0236 ,  C21D8/0263 ,  C21D1/74 ,  C21D8/0278 ,  C25D3/20 ,  C25D5/36 ,  C21D2251/02 ,  C23C2/28

Abstract: Provided is an alloyed galvanized steel sheet with excellent resistance to cracking in resistance welding at a welded portion, even if crystal orientations of an Fe-based electroplating layer and a cold-rolled steel sheet are integrated at a high ratio at the interface between the Fe-based electroplating layer and the cold-rolled steel sheet. The alloyed galvanized steel sheet has a Si-containing cold-rolled steel sheet containing Si in an amount of 0.1 mass % to 3.0 mass %; an Fe-based electroplating layer formed on at least one surface of the Si-containing cold-rolled steel sheet with a coating weight per surface exceeding 20.0 g/m2, and an alloyed galvanized layer formed on the Fe-based electroplating layer, where crystal orientations of the Fe-based electroplating layer and the Si-containing cold-rolled steel sheet are integrated at a ratio of more than 50% at the interface between the Fe-based electroplating layer and the Si-containing cold-rolled steel sheet.