公开(公告)号：US20170348790A1

公开(公告)日：2017-12-07

申请号：US15545757

申请日：2016-01-22

Applicant: JFE Steel Corporation

Inventor： Hiroshi Matsuda ,  Yasuaki Okita ,  Muneo Matsushita ,  Rinsei Ikeda ,  Kenji Oi

IPC: B23K11/16 ,  C22C38/06 ,  B23K11/11 ,  C22C38/00 ,  C22C38/02 ,  C22C38/18 ,  C22C38/04 ,  B23K103/04

CPC classification number: B23K11/163 ,  B23K11/11 ,  B23K11/16 ,  B23K11/34 ,  B23K2103/04 ,  B32B15/04 ,  C22C38/00 ,  C22C38/001 ,  C22C38/002 ,  C22C38/02 ,  C22C38/04 ,  C22C38/06 ,  C22C38/18 ,  C22C38/60

Abstract: A steel sheet assembly includes a plurality of lapped steel sheets which have a tensile strength of 1,470 MPa or less and a thickness of 0.3 mm to 5.0 mm, the steel sheet assembly being formed by applying, in advance, an adhesive and a carbon-supplying agent to a surface of either or both of the steel sheets to be lapped and then welding the steel sheets. A weld of the assembly has a nugget diameter of 2.8√t (mm) or more, where t (mm) denotes the thickness of a thinner one of the steel sheets on both sides of a weld interface, and the amount of C is increased by 0.02 % by mass or more as compared to the steel sheets before being applied with the adhesive and the carbon-supplying agent.

公开(公告)号：US20170191141A1

公开(公告)日：2017-07-06

申请号：US15462241

申请日：2017-03-17

Applicant: JFE Steel Corporation

Inventor： Hiroshi Matsuda ,  Tatsuya Nakagaito ,  Takayuki Futatsuka ,  Shusaku Takagi ,  Yasunobu Nagataki

IPC: C21D9/46 ,  C23F17/00 ,  C22C38/40 ,  C22C38/32 ,  C22C38/28 ,  C22C38/02 ,  C22C38/24 ,  C22C38/22 ,  C22C38/20 ,  C22C38/06 ,  C22C38/04 ,  C22C38/00 ,  C23C2/06 ,  C22C38/26

CPC classification number: C21D9/46 ,  B32B15/013 ,  C21D2211/001 ,  C22C38/002 ,  C22C38/02 ,  C22C38/04 ,  C22C38/06 ,  C22C38/20 ,  C22C38/22 ,  C22C38/24 ,  C22C38/26 ,  C22C38/28 ,  C22C38/32 ,  C22C38/38 ,  C22C38/40 ,  C23C2/02 ,  C23C2/06 ,  C23C2/28 ,  C23F17/00

Abstract: A high-strength hot-dip galvanized steel sheet excellent in formability includes, on the basis of mass percent, 0.05-0.3% C, 1.4% or less (including 0%) Si, 0.08%-3% Mn, 0.003-0.1% P, 0.07% or less S, 0.1-2.5% Al, 0.1-0.5% Cr, and 0.007% or less N, Si+Al≧0.5%, and the balance being Fe and incidental impurities, wherein the steel sheet has a retained austenite content of 3% or more by volume fraction, a stretch-flange formability λ>50% and wherein the average aspect ratio (major axis/minor axis) of retained austenite grains is less than 2.5.

公开(公告)号：US20170113295A1

公开(公告)日：2017-04-27

申请号：US15317354

申请日：2015-06-05

Applicant: JFE STEEL CORPORATION

Inventor： Chikaumi Sawanishi ,  Yasuaki Okita ,  Hiroshi Matsuda ,  Rinsei Ikeda

IPC: B23K11/25

CPC classification number: B23K11/252 ,  B23K11/115 ,  B23K11/257 ,  B23K11/258 ,  B23K2101/006 ,  B23K2101/18 ,  B23K2103/04

Abstract: A resistance spot welding device that joins predetermined parts to be welded includes: a storage configured to store a time variation of an instantaneous amount of heat generated per unit volume and a cumulative amount of heat generated per unit volume in test welding that precedes actual welding; and an adaptive controller and an electrode force controller configured to, in the case where the time variation of the instantaneous amount of heat generated per unit volume in the actual welding differs from a time variation curve stored as the target value, respectively control the current or a voltage during current passage and the electrode force to the parts to be welded to compensate for the difference within a remaining welding time so that the cumulative amount of heat generated per unit volume in the actual welding matches the cumulative amount of heat generated per unit volume stored in the storage.

公开(公告)号：US12151299B2

公开(公告)日：2024-11-26

申请号：US17252728

申请日：2019-06-17

Applicant: JFE STEEL CORPORATION

Inventor： Chikaumi Sawanishi ,  Hiroshi Matsuda ,  Rinsei Ikeda

IPC: B23K11/25 ,  B23K11/11 ,  B23K101/18

Abstract: A resistance spot welding method comprises: performing test welding; and performing actual welding after the test welding, wherein in main current passage in the actual welding, adaptive control welding is performed, and in subsequent current passage in the actual welding, current passage is performed by constant current control with a current determined based on an electrical property between electrodes in each of main current passage in the test welding and the main current passage in the actual welding.

公开(公告)号：US12037665B2

公开(公告)日：2024-07-16

申请号：US17414111

申请日：2019-12-19

Applicant: JFE Steel Corporation

Inventor： Minoru Tanaka ,  Koichi Taniguchi ,  Rinta Sato ,  Katsutoshi Takashima ,  Hiroshi Matsuda ,  Rinsei Ikeda

IPC: C22C38/02 ,  B23K11/00 ,  B23K11/11 ,  B23K11/16 ,  B23K101/18 ,  B23K101/34 ,  B23K103/04 ,  C22C18/04 ,  C22C38/04 ,  C23C2/06 ,  C23C2/28 ,  C23C2/40

CPC classification number: C22C38/02 ,  B23K11/0026 ,  B23K11/115 ,  B23K11/166 ,  C22C18/04 ,  C22C38/04 ,  C23C2/06 ,  C23C2/28 ,  C23C2/40 ,  B23K2101/18 ,  B23K2101/34 ,  B23K2103/04

Abstract: A spot welded member includes a spot weld formed by holding a sheet stack of multiple steel sheets between a pair of electrodes and spot-welding the sheet stack, in which at least one of the multiple steel sheets is a high-strength zinc-based coated steel sheet having a tensile strength of 780 MPa or more, the high-strength zinc-based coated steel sheet having a coating with an Al content of 0.5% or more by mass, and in which the heat shock region of the spot weld outwardly extending from an edge of a corona bond area includes a coated layer including an FeAl alloy layer having an average thickness of 0.3 μm or more and a zinc-based coated layer having an average thickness of 2.0 μm or more on the FeAl alloy layer at the interface between the base steel sheet of the high-strength zinc-based coated steel sheet and the coating.

公开(公告)号：US11946112B2

公开(公告)日：2024-04-02

申请号：US17270613

申请日：2019-08-22

Applicant: JFE Steel Corporation

Inventor： Yoshihiko Ono ,  Yuma Honda ,  Shimpei Yoshioka ,  Koichi Taniguchi ,  Hiroshi Matsuda ,  Takeshi Murai ,  Nobuyuki Nakamura

IPC: C21D9/46 ,  C21D6/00 ,  C21D8/02 ,  C22C38/00 ,  C22C38/02 ,  C22C38/04 ,  C22C38/06 ,  C22C38/08 ,  C22C38/12 ,  C22C38/14 ,  C22C38/16 ,  C22C38/42 ,  C22C38/44 ,  C22C38/46 ,  C22C38/48 ,  C22C38/50 ,  C22C38/54 ,  C22C38/58 ,  C22C38/60 ,  C23C2/02 ,  C23C2/06 ,  C23C2/40

CPC classification number: C21D9/46 ,  C21D6/005 ,  C21D6/008 ,  C21D8/0205 ,  C21D8/0226 ,  C21D8/0236 ,  C21D8/0247 ,  C22C38/001 ,  C22C38/002 ,  C22C38/005 ,  C22C38/008 ,  C22C38/02 ,  C22C38/04 ,  C22C38/06 ,  C22C38/08 ,  C22C38/12 ,  C22C38/14 ,  C22C38/16 ,  C22C38/42 ,  C22C38/44 ,  C22C38/46 ,  C22C38/48 ,  C22C38/50 ,  C22C38/54 ,  C22C38/58 ,  C22C38/60 ,  C23C2/02 ,  C23C2/0224 ,  C23C2/024 ,  C23C2/06 ,  C23C2/40 ,  C21D2211/001 ,  C21D2211/002 ,  C21D2211/005 ,  C21D2211/008

Abstract: A high-strength steel sheet of the present invention has a specific chemical composition. Furthermore, in the steel sheet, a degree of Mn segregation in a specific region is 1.5 or less; a maximum P concentration in a specific region is 0.08 mass % or less; in a specific region, at least one specific MnS particle group is present, the number of specific MnS particle groups is 2.0 or fewer per 1 mm2, and the number of specific oxide-based inclusions is 8 or fewer per 1 mm2; of all oxide-based inclusions, oxide-based inclusions having a specific composition are present in a number ratio of 80% or greater; the microstructure includes, in terms of a volume fraction, 30 to 95% martensite, 5 to 70% ferrite phase, less than 30% (and 0% or greater) bainite, and less than 2.0% (and 0% or greater) austenite phase; and a tensile strength is 980 MPa or greater.

公开(公告)号：US11498150B2

公开(公告)日：2022-11-15

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 ,  B23K103/08 ,  B23K103/04 ,  B23K11/11

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：US20220339731A1

公开(公告)日：2022-10-27

申请号：US17762486

申请日：2020-07-27

Applicant: JFE Steel Corporation

Inventor： Nao Kawabe ,  Hiroshi Matsuda

IPC: B23K11/11 ,  B23K11/16

Abstract: A resistance spot welding method is disclosed for joining two or more steel sheets including at least one steel sheet having a tensile strength of 980 MPa or higher. The resistance spot welding method involves placing the steel sheets on top of each other to form a set of steel sheets to be welded, clamping the set of steel sheets with a pair of electrodes, and passing a current through the steel sheets while applying pressure thereto to join the steel sheets together. The resistance spot welding method includes an initial welding step of welding by passing a current I1 (kA) satisfying 2×√F1

公开(公告)号：US11298773B2

公开(公告)日：2022-04-12

申请号：US16488703

申请日：2018-03-01

Applicant: JFE Steel Corporation

Inventor： Koichi Taniguchi ,  Chikaumi Sawanishi ,  Katsutoshi Takashima ,  Hiroshi Matsuda ,  Rinsei Ikeda

IPC: B23K11/11 ,  B23K11/00 ,  B23K11/16 ,  B23K103/04

Abstract: Provided is a resistance spot welding method. The resistance spot welding method for joining a sheet set including a plurality of lapped steel sheets includes: holding the sheet set between a pair of electrodes; and energizing the sheet set under application of electrode force to thereby join the steel sheets together. At least one of the plurality of lapped steel sheets is a surface-treated steel sheet including a metal coating layer on a surface thereof. The energizing includes: a primary energizing step of performing energization to form a nugget portion; a non-energizing step in which, after the primary energizing step, the energization is suspended for an energization suspension time Tc (cycles); and a secondary energizing step of, after the non-energizing step, performing energization for reheating while the nugget portion is prevented from growing. During the energizing, the relations of a particular formula are satisfied.

公开(公告)号：US20210362266A1

公开(公告)日：2021-11-25

申请号：US16967193

申请日：2019-02-05

Applicant: JFE Steel Corporation

Inventor： Reiko Endo ,  Muneo Matsushita ,  Koichi Taniguchi ,  Hiroshi Matsuda ,  Rinsei Ikeda

IPC: B23K11/11 ,  B23K11/16 ,  B23K11/24 ,  C21D9/50 ,  C22C38/54 ,  C22C38/50 ,  C22C38/48 ,  C22C38/46 ,  C22C38/44 ,  C22C38/42 ,  C22C38/06 ,  C21D6/00 ,  C22C38/00 ,  C22C38/02 ,  C22C38/04

Abstract: The present invention provides a resistance spot welding method. A resistance spot welding method according to the present invention in which a sheet combination of two or more overlapping steel sheets is sandwiched between a pair of electrodes and joined together by applying current while applying pressure, the method including a main current application step in which current application is performed with a current Iw (kA), and subsequently, a post-tempering heat treatment step in which after cooling is performed for a cooling time tct (ms) shown in formula (1) below, current application is performed with a current It (kA) shown in formula (2) below for a current application time tt (ms) shown in formula (3) below: 800≤tct . . . formula (1), 0.5×Iw≤It≤Iw . . . formula (2), and 500≤tt . . . formula (3).