公开(公告)号：US20230407506A1

公开(公告)日：2023-12-21

申请号：US18251396

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: C25D3/20 ,  C21D9/46 ,  C22C38/00 ,  C22C38/02 ,  C22C38/06 ,  C22C38/04 ,  C21D8/02 ,  C23C22/78 ,  C25D5/36 ,  C23C28/02

CPC classification number: C25D3/20 ,  C21D9/46 ,  C22C38/001 ,  C22C38/002 ,  C22C38/02 ,  C22C38/06 ,  C22C38/04 ,  C21D8/0236 ,  C21D8/0273 ,  C23C22/78 ,  C25D5/36 ,  C23C28/02 ,  C21D2201/05

Abstract: Provided is a steel sheet with excellent resistance to cracking in resistance welding at a welded portion, even if the crystal orientations of an Fe-based electroplating layer and a Si-containing cold-rolled steel sheet are integrated at a high ratio at the interface between the Fe-based electroplating layer and the Si-containing cold-rolled steel sheet. Provided is an Fe-based electroplated steel sheet having 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 more than 20.0 g/m2, where the 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.

公开(公告)号：US20230374639A1

公开(公告)日：2023-11-23

申请号：US18250979

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: C23C2/40 ,  C21D8/02 ,  C21D9/46 ,  C23C2/06 ,  C22C38/02 ,  C22C38/00 ,  C22C38/04 ,  C22C38/06 ,  C25D3/20 ,  C25D5/36 ,  C25D5/50 ,  C25D7/06 ,  C23C28/02

CPC classification number: C23C2/40 ,  C21D8/0236 ,  C21D9/46 ,  C23C2/06 ,  C22C38/02 ,  C22C38/001 ,  C22C38/002 ,  C22C38/04 ,  C22C38/06 ,  C25D3/20 ,  C25D5/36 ,  C25D5/50 ,  C25D7/0614 ,  C23C28/021

Abstract: To provide a steel sheet with excellent resistance to cracking in resistance welding at a welded portion. Disclosed is a galvanized 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; 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; and a galvanized layer formed on the Fe-based electroplating layer, in which in an intensity profile measured by glow discharge optical emission spectrometry, ISi,Fe/ISi,bulk is 0.50 or more, and an average value of C concentration in a region ranging from 10 μm to 20 μm from an interface between the galvanized layer and the Fe-based electroplating layer towards the Fe-based electroplating layer is 0.10 mass % or less.

公开(公告)号：US20230295762A1

公开(公告)日：2023-09-21

申请号：US18021287

申请日：2021-06-22

Applicant: JFE STEEL CORPORATION

Inventor： Katsutoshi TAKASHIMA ,  Yoshie OBATA ,  Hiroshi MATSUDA

IPC: C21D9/46 ,  B32B15/01 ,  C21D6/00 ,  C22C38/60 ,  C22C38/14 ,  C22C38/12 ,  C22C38/06 ,  C22C38/04 ,  C22C38/02 ,  C22C38/00

CPC classification number: C21D9/46 ,  B32B15/013 ,  C21D6/005 ,  C21D6/008 ,  C22C38/60 ,  C22C38/14 ,  C22C38/12 ,  C22C38/06 ,  C22C38/04 ,  C22C38/02 ,  C22C38/002 ,  C22C38/001 ,  C21D2211/008 ,  C21D2211/003 ,  C21D2211/001

Abstract: A hot-pressed member having a specified chemical composition in which Ti/Sb 2.0≤Ti/Sb≤20.0 is satisfied and a method for producing the hot-pressed member. The hot-pressed member has a microstructure in which a volume fraction of martensite is 95% or more, an average grain size of prior austenite is 7 μm or less, the number of cementite grains with a grain size of 0.10 μm or more is 2 grains/μm2 or more, and the number of Ti-based carbide grains with a grain size of 0.10 μm or less is 0.20 grains/μm2 or more, and a tensile strength of 2100 MPa or higher.

公开(公告)号：US20220186339A1

公开(公告)日：2022-06-16

申请号：US17432218

申请日：2020-01-17

Applicant: JFE STEEL CORPORATION

Inventor： Katsutoshi TAKASHIMA ,  Minoru TANAKA ,  Yoshie OBATA ,  Michitaka SAKURAI

IPC: C21D9/48 ,  C21D8/04 ,  C21D6/00 ,  C22C38/60 ,  C22C38/54 ,  C22C38/50 ,  C22C38/48 ,  C22C38/46 ,  C22C38/44 ,  C22C38/42 ,  C22C38/06 ,  C22C38/58 ,  C22C38/00 ,  C22C38/02 ,  B32B15/01

Abstract: Provided is a hot-pressed member that combines both high strength of 1850 MPa or more in TS and excellent delayed fracture resistance. A hot-pressed member comprises: a predetermined chemical composition; a microstructure in which a prior austenite average grain size is 8 μm or less, a volume fraction of martensite is 95% or more, and a volume fraction of granular carbide of 0.1 μm or more in grain size is 0.10% to 4.0%; a Ni diffusion region of 2.0 μm or more in a depth direction in a surface layer; and a tensile strength of 1850 MPa or more.

公开(公告)号：US20200269342A1

公开(公告)日：2020-08-27

申请号：US16645789

申请日：2018-08-14

Applicant: JFE STEEL CORPORATION

Inventor： Koichi TANIGUCHI ,  Reiko ENDO ,  Katsutoshi TAKASHIMA ,  Hiroshi MATSUDA ,  Rinsei IKEDA

IPC: B23K11/16

Abstract: Main current passage and subsequent current passage are performed, with a cooling time of 0.01 s or more being provided between the main current passage and the subsequent current passage. Ip/I which is a ratio of a current value of the subsequent current passage to a current value of the main current passage is controlled to satisfy a predetermined relationship depending on a constant A defined by Mn content and P content of a steel sheet as a part to be welded, in relation to a welding time Tp of the subsequent current passage, a cooling time T, and the constant A.

公开(公告)号：US20180257165A1

公开(公告)日：2018-09-13

申请号：US15755118

申请日：2016-08-23

Applicant: JFE Steel Corporation

Inventor： Chikaumi SAWANISHI ,  Koichi TANIGUCHI ,  Katsutoshi TAKASHIMA ,  Hiroshi MATSUDA ,  Rinsei IKEDA

IPC: B23K11/11 ,  B23K11/16

CPC classification number: B23K11/11 ,  B23K11/115 ,  B23K11/16 ,  B23K11/163 ,  B23K2103/04

Abstract: A resistance spot welding method inhibits, in accordance with the electrode angle, the occurrence of cracking in the weld regardless of the steel grade. The resistance spot welding method satisfies relationships: 2·A·(t·T/F)1/2≤H when 0≤A

公开(公告)号：US20240424595A1

公开(公告)日：2024-12-26

申请号：US18698216

申请日：2022-09-29

Applicant: JFE STEEL CORPORATION

Inventor： Reiko ENDO ,  Katsutoshi TAKASHIMA ,  Hiroshi MATSUDA

IPC: B23K11/11 ,  F16B5/08

Abstract: A resistance spot welded joint having a resistance spot weld formed by resistance-spot-welding two or more steel sheets includes at least one high strength steel sheet. The high strength steel sheet has a specific chemical composition. The hardness Hv1 of a first region of a heat-affected zone and the hardness Hmv of martensite in a nugget as a whole satisfy the relation Hv1≤0.78×Hmw, and the hardness Hv2 of a second region of the heat-affected zone and the hardness Hv1 of the first region satisfy the relation Hv2≥1.10×Hv1. The hardness Hv3 of a third region of the heat-affected zone and the hardness Hv2 of the second region satisfy the relation Hv3≤0.90×Hv2.

公开(公告)号：US20240352959A1

公开(公告)日：2024-10-24

申请号：US18682746

申请日：2022-07-21

Applicant: JFE STEEL CORPORATION

Inventor： Reiko ENDO ,  Katsutoshi TAKASHIMA ,  Hiroshi MATSUDA

IPC: F16B5/08 ,  B23K11/11

CPC classification number: F16B5/08 ,  B23K11/115

Abstract: A resistance spot welded joint is formed by resistance-spot-welding two or more steel sheets including at least one high strength steel sheet. The high strength steel sheet has a chemical composition containing, in mass %, C: 0.05 to 0.6%, Si: 0.1 to 2.0%, Mn: 1.5 to 4.0%, and P: 0.10% or less, with the balance being Fe and incidental impurities. The hardness of a softest nugget region is 90% or less of the hardness of the heat-affected zone. The softest nugget region has a microstructure including tempered martensite. The average number density of carbide particles having a diameter of 100 nm or more in the softest nugget region is 10 or more per 5 μm2 in a cross section of the steel sheets.

公开(公告)号：US20240246167A1

公开(公告)日：2024-07-25

申请号：US18561363

申请日：2022-03-14

Applicant: JFE STEEL CORPORATION

Inventor： Katsutoshi TAKASHIMA ,  Reiko ENDO ,  Lingling YANG ,  Hiroshi MATSUDA

IPC: B23K11/16 ,  B23K11/00 ,  B23K11/11 ,  B23K101/00 ,  B23K103/04 ,  C22C38/00 ,  C22C38/02 ,  C22C38/04 ,  C22C38/06 ,  C22C38/12 ,  C22C38/14 ,  C22C38/20 ,  C22C38/22 ,  C22C38/46 ,  C22C38/54

CPC classification number: B23K11/166 ,  B23K11/0026 ,  B23K11/11 ,  B23K2101/006 ,  B23K2103/04 ,  C22C38/001 ,  C22C38/002 ,  C22C38/005 ,  C22C38/02 ,  C22C38/04 ,  C22C38/06 ,  C22C38/12 ,  C22C38/14 ,  C22C38/20 ,  C22C38/22 ,  C22C38/46 ,  C22C38/54

Abstract: An automotive member and a resistance spot welding method. The automotive member includes a resistance spot weld formed by resistance-spot-welding a plurality of steel sheets including at least one high strength steel sheet. The high strength steel sheet has a specific chemical composition. The microstructure in the vicinity of the edge of the nugget of the resistance spot weld is a composite microstructure containing ferrite at a volume fraction of 1 to 30%, martensite at a volume fraction of 1 to 50%, and tempered martensite at a volume fraction of 20% or more. The average number density of Nb-based precipitate grains having a grain diameter less than 0.09 μm and Ti-based precipitate grains having a grain diameter less than 0.09 μm is 10 or more grains per 100 μm2 in a sheet cross section.

公开(公告)号：US20230407447A1

公开(公告)日：2023-12-21

申请号：US18251422

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: C23C2/02 ,  C22C33/04 ,  C22C38/16 ,  C22C38/14 ,  C22C38/12 ,  C22C38/08 ,  C22C38/06 ,  C22C38/04 ,  C22C38/02 ,  C22C38/38 ,  C22C38/32 ,  C22C38/28 ,  C21D9/46 ,  C21D8/02 ,  C21D6/00 ,  C22C38/00 ,  C21D1/74 ,  C25D5/36 ,  C25D5/48 ,  C25D3/56 ,  C23C2/28 ,  C23C2/40 ,  C23F17/00 ,  C23C28/00

CPC classification number: C23C2/02 ,  C22C33/04 ,  C22C38/16 ,  C22C38/14 ,  C22C38/12 ,  C22C38/08 ,  C22C38/06 ,  C22C38/04 ,  C22C38/02 ,  C22C38/38 ,  C22C38/32 ,  C22C38/28 ,  C21D9/46 ,  C21D8/0205 ,  C21D8/0226 ,  C21D8/0236 ,  C21D8/0263 ,  C21D8/0278 ,  C21D6/002 ,  C21D6/005 ,  C21D6/008 ,  C22C38/002 ,  C22C38/001 ,  C21D1/74 ,  C25D5/36 ,  C25D5/48 ,  C25D3/562 ,  C23C2/28 ,  C23C2/40 ,  C23F17/00 ,  C23C28/34 ,  C23C28/321 ,  C21D2251/02 ,  B23K11/166

Abstract: Provided is a 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 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 of more than 20.0 g/m2, and a 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.