公开(公告)号：US10550446B2

公开(公告)日：2020-02-04

申请号：US15520531

申请日：2015-10-29

Applicant: JFE STEEL CORPORATION

Inventor： Yoshiyasu Kawasaki ,  Hiroshi Matsuda ,  Takeshi Yokota ,  Takako Yamashita ,  Kazuhiro Seto

IPC: C22C38/04 ,  C22C38/58 ,  C21D8/02 ,  C22C38/38 ,  C21D6/00 ,  C21D9/46 ,  C23C2/02 ,  C23C2/06 ,  C23C2/12 ,  C23C2/28 ,  C22C38/00 ,  C22C38/14 ,  C22C38/60 ,  B32B15/01 ,  C22C38/02 ,  C22C38/06 ,  C22C38/08 ,  C22C38/12 ,  C22C38/16 ,  C22C38/28 ,  C23C2/40 ,  C23G1/00 ,  C25D3/22

Abstract: A high-strength steel sheet with excellent formability and high yield ratio that has TS of 980 MPa or more and YR of 68% or more is obtained by providing a predetermined chemical composition and a steel microstructure that contains, in area ratio, 15 to 55% of polygonal ferrite, 8% or more of non-recrystallized ferrite, and 15 to 30% of martensite, and that contains, in volume fraction, 12% or more of retained austenite, in which the polygonal ferrite has a mean grain size of 4 μm or less, the martensite has a mean grain size of 2 μm or less, the retained austenite has a mean grain size of 2 μm or less, and a value obtained by dividing an Mn content in the retained austenite (in mass %) by an Mn content in the polygonal ferrite (in mass %) equals 2.0 or more.

公开(公告)号：US20190201999A1

公开(公告)日：2019-07-04

申请号：US16323570

申请日：2017-08-21

Applicant: JFE Steel Corporation

Inventor： Katsutoshi Takashima ,  Hiroshi Matsuda ,  Rinsei Ikeda ,  Yoshiyasu Kawasaki

IPC: B23K11/16 ,  F16B5/08 ,  C22C38/38 ,  C22C38/28 ,  C22C38/26 ,  C22C38/16 ,  C22C38/08 ,  C22C38/06 ,  C22C38/02 ,  C22C38/00 ,  C21D9/46 ,  C21D8/02 ,  C21D6/00 ,  B32B15/01

CPC classification number: B23K11/16 ,  B23K11/0026 ,  B23K11/115 ,  B23K11/166 ,  B23K11/20 ,  B23K2101/006 ,  B23K2101/18 ,  B23K2101/34 ,  B23K2103/04 ,  B23K2103/18 ,  B32B15/01 ,  B32B15/013 ,  C21D6/001 ,  C21D6/002 ,  C21D6/005 ,  C21D6/008 ,  C21D8/0205 ,  C21D8/0226 ,  C21D8/0236 ,  C21D8/0263 ,  C21D9/46 ,  C21D2211/001 ,  C22C38/001 ,  C22C38/002 ,  C22C38/005 ,  C22C38/02 ,  C22C38/04 ,  C22C38/06 ,  C22C38/08 ,  C22C38/12 ,  C22C38/14 ,  C22C38/16 ,  C22C38/26 ,  C22C38/28 ,  C22C38/38 ,  C23C2/00 ,  F16B5/08

Abstract: Provided is an automotive member, or particularly, a steel sheet having a tensile strength exceeding 900 MPa. The automotive member has a resistance weld for fixing two or more steel sheets containing a predetermined composition, in which a maximum hardness (HVBM) in a heat-affected zone of the resistance weld is at least 1.1 times hardness (HVW) of a nugget in the resistance weld formed in a softest steel sheet of a sheet set during resistance welding, and furthermore, an average grain size of a steel sheet structure of the heat-affected zone within 2 mm in a direction at a right angle to a sheet thickness from an end part of the nugget of the high-strength steel sheet is 3 μm or less, and a minimum hardness (HVmin) in the heat-affected zone is at least 90% of hardness (HVα) of the high-strength steel sheet before the resistance welding.

公开(公告)号：US09953752B2

公开(公告)日：2018-04-24

申请号：US14650378

申请日：2013-12-25

Applicant: JFE STEEL CORPORATION

Inventor： Yukihiro Shingaki ,  Hiroi Yamaguchi ,  Yuiko Wakisaka ,  Hiroshi Matsuda ,  Takashi Terashima

IPC: H01F1/147 ,  C21D8/12 ,  C21D9/46 ,  C21D6/00 ,  H01F1/18 ,  H01F41/02 ,  H01F41/00 ,  C23C8/26 ,  C22C38/60 ,  H01F1/16 ,  C22C38/00 ,  C22C38/02 ,  C22C38/04 ,  C22C38/06 ,  C22C38/08 ,  C22C38/12 ,  C22C38/16 ,  C22C38/22

CPC classification number: H01F1/14783 ,  C21D6/005 ,  C21D6/008 ,  C21D8/1222 ,  C21D8/1233 ,  C21D8/1255 ,  C21D8/1261 ,  C21D8/1272 ,  C21D9/46 ,  C22C38/001 ,  C22C38/002 ,  C22C38/008 ,  C22C38/02 ,  C22C38/04 ,  C22C38/06 ,  C22C38/08 ,  C22C38/12 ,  C22C38/16 ,  C22C38/22 ,  C22C38/60 ,  C23C8/26 ,  H01F1/16 ,  H01F1/18 ,  H01F41/005 ,  H01F41/02

Abstract: A method for producing grain-oriented electrical steel sheets includes subjecting a steel slab to hot rolling to obtain a hot rolled sheet, the steel slab having a composition consisting of, by mass % or mass ppm, C: 0.08% or less, Si: 2.0% to 4.5% and Mn: 0.5% or less, S, Se, and O: less than 50 ppm each, sol.Al: less than 100 ppm, N: 80 ppm or less, and the balance being Fe and incidental impurities, and satisfying the relation of sol.Al (ppm)−N (ppm)×(26.98/14.00)≤30 ppm; then subjecting the hot rolled sheet to annealing and rolling to obtain a cold rolled sheet; then subjecting the cold rolled sheet to nitriding treatment, under specific condition, before, during or after primary recrystallization annealing; then applying an annealing separator on the cold rolled sheet; and subjecting the cold rolled sheet to secondary recrystallization annealing.

公开(公告)号：US09905343B2

公开(公告)日：2018-02-27

申请号：US14650073

申请日：2013-12-25

Applicant: JFE STEEL CORPORATION

Inventor： Yukihiro Shingaki ,  Yasuyuki Hayakawa ,  Hiroi Yamaguchi ,  Hiroshi Matsuda ,  Yuiko Wakisaka

IPC: H01F1/147 ,  C21D8/12 ,  C22C38/00 ,  C22C38/06 ,  C22C38/04 ,  H01F41/02 ,  C23C8/26 ,  C23C8/50 ,  C22C38/60 ,  H01F1/16 ,  C22C38/02 ,  C23C8/02 ,  C23C8/80 ,  C21D6/00

CPC classification number: H01F1/14775 ,  C21D6/008 ,  C21D8/1222 ,  C21D8/1233 ,  C21D8/1255 ,  C21D8/1261 ,  C21D8/1272 ,  C21D8/1283 ,  C21D8/1294 ,  C21D2211/004 ,  C22C38/002 ,  C22C38/02 ,  C22C38/04 ,  C22C38/06 ,  C22C38/60 ,  C23C8/02 ,  C23C8/26 ,  C23C8/50 ,  C23C8/80 ,  H01F1/16 ,  H01F41/02

Abstract: A method for producing a grain-oriented electrical steel sheets includes subjecting a steel slab to hot rolling to obtain a hot rolled sheet, the steel slab having a specific composition; then subjecting the hot rolled sheet to annealing and rolling to obtain a cold rolled sheet; then subjecting the cold rolled sheet to nitriding treatment with a nitrogen increase of 50 to 1000 ppm, during or after primary recrystallization annealing; then applying an annealing separator on the cold rolled sheet; and setting the staying time in a temperature range of 300 to 800° C. in the secondary recrystallization annealing to 5 to 150 hours.

公开(公告)号：US09708682B2

公开(公告)日：2017-07-18

申请号：US14650387

申请日：2013-12-25

Applicant: JFE STEEL CORPORATION

Inventor： Yasuyuki Hayakawa ,  Yukihiro Shingaki ,  Hiroi Yamaguchi ,  Hiroshi Matsuda ,  Yuiko Wakisaka

IPC: C21D8/12 ,  C23C8/26 ,  C23C8/50 ,  C22C38/60 ,  H01F1/16 ,  C22C38/00 ,  C22C38/02 ,  C22C38/04 ,  C22C38/08 ,  C22C38/12 ,  C22C38/16 ,  C22C38/22 ,  C23C8/02 ,  C23C8/80 ,  C21D1/26 ,  C21D6/00 ,  C21D9/46 ,  C22C38/06 ,  C22C38/20 ,  C22C38/26 ,  C22C38/34 ,  C22C38/42 ,  C22C38/44 ,  C22C38/48 ,  C23C8/04 ,  H01F1/147 ,  H01F41/02

CPC classification number: C21D8/1261 ,  C21D1/26 ,  C21D6/001 ,  C21D6/002 ,  C21D6/004 ,  C21D6/005 ,  C21D6/008 ,  C21D8/1222 ,  C21D8/1233 ,  C21D8/1255 ,  C21D8/1272 ,  C21D8/1283 ,  C21D9/46 ,  C22C38/001 ,  C22C38/002 ,  C22C38/008 ,  C22C38/02 ,  C22C38/04 ,  C22C38/06 ,  C22C38/08 ,  C22C38/12 ,  C22C38/16 ,  C22C38/20 ,  C22C38/22 ,  C22C38/26 ,  C22C38/34 ,  C22C38/42 ,  C22C38/44 ,  C22C38/48 ,  C22C38/60 ,  C23C8/02 ,  C23C8/04 ,  C23C8/26 ,  C23C8/50 ,  C23C8/80 ,  H01F1/14783 ,  H01F1/16 ,  H01F41/02

Abstract: Grain-oriented electrical steel sheets with good magnetic properties are industrially stably produced, by using as the material, a steel slab having a predetermined composition, wherein after cold rolling and before the start of secondary recrystallization annealing, the cold rolled sheet is subjected to nitriding treatment with nitrogen content of 50 mass ppm or more and 1000 mass ppm or less, and a total content of 0.2 mass % to 15 mass % of a sulfide and/or sulfate is contained in an annealing separator, and a staying time in the temperature range of 300° C. to 800° C. in the heating stage of secondary recrystallization annealing of 5 hours or more is secured to precipitate silicon nitride (Si3N4) and MnS, and using the silicon nitride in combination with MnS as inhibiting force for normal grain growth to significantly reduce variation of magnetic properties.

公开(公告)号：US20150332822A1

公开(公告)日：2015-11-19

申请号：US14387953

申请日：2013-03-29

Applicant: JFE Steel Corporation

Inventor： Masanori Takenaka ,  Toshito Takamiya ,  Hiroshi Matsuda

IPC: H01F1/147 ,  C21D9/46 ,  C22C38/60 ,  C22C38/08 ,  H01F41/02 ,  C22C38/04 ,  C22C38/02 ,  C22C38/00 ,  C22C38/16 ,  C21D8/12 ,  C22C38/06

CPC classification number: H01F1/14775 ,  C21D8/1222 ,  C21D8/1233 ,  C21D8/1261 ,  C21D8/1266 ,  C21D8/1272 ,  C21D8/1288 ,  C21D9/46 ,  C22C38/001 ,  C22C38/008 ,  C22C38/02 ,  C22C38/04 ,  C22C38/06 ,  C22C38/08 ,  C22C38/16 ,  C22C38/60 ,  H01F1/16 ,  H01F41/02

Abstract: A method of manufacturing a grain oriented electrical steel sheet uses austenite (γ)-ferrite (α) transformation which develops excellent magnetic properties, uses Tα calculated from equation (1) and performs the first pass of rough hot rolling at a temperature of (Tα−100)° C. or higher with a rolling reduction of 30% or more, and further uses Tγmax calculated from equation (2) and performs any one pass of finish hot rolling in a temperature range of (Tγmax±50)° C. with a rolling reduction of 40% or more: Tα[° C.]=1383.98−73.29[% Si]+2426.33[% C]+271.68[% Ni]  (1) Tγmax[° C.]=1276.47−59.24[% Si]+919.22[% C]+149.03[% Ni]  (2) where [% A] represents content of element “A” in steel (mass %).

Abstract translation: 晶粒取向电工钢板的制造方法使用产生优异磁性的奥氏体（γ） - 铁素体（α）相变，使用式（1）计算出的Tα，在（Tα）的温度下进行粗热轧的第一道次 -100）℃以上，轧制压下率为30％以上，进一步使用式（2）所算出的Tγmax，在（Tγmax±50）℃的温度范围内进行精加工热轧。 压下率为40％以上：Tα[℃] = 1383.98-73.29 [％Si] +2426.33 [％C] +271.68 [％Ni]（1）Tγmax[℃] = 1276.47-59.24 [ ％Si] +919.22 [％C] +149.03 [％Ni]（2）其中[％A]表示钢中元素“A”的含量（质量％）。

公开(公告)号：US11911837B2

公开(公告)日：2024-02-27

申请号：US16969976

申请日：2019-02-18

Applicant: JFE STEEL CORPORATION

Inventor： Chikaumi Sawanishi ,  Hiroshi Matsuda ,  Rinsei Ikeda

IPC: B23K11/11 ,  B23K11/25

CPC classification number: B23K11/115 ,  B23K11/257

Abstract: A resistance spot welding method comprises: performing test welding; and performing actual welding after the test welding, wherein the test welding is performed under each of two or more welding conditions. In the test welding, for each of the welding conditions, an electrode force parameter from when electrode force application to parts to be welded starts to when a set electrode force is reached before start of current passage and a time variation curve of an instantaneous amount of heat generated and a cumulative amount of heat generated are stored. In the actual welding: electrode force application to the parts to be welded is performed under each of the same conditions as in the test welding before start of current passage, and a corresponding electrode force parameter and the parameter stored in the test welding are compared for each of the welding conditions to set a target of a time variation curve of an instantaneous amount of heat generated and a cumulative amount of heat generated in the actual welding; and adaptive control welding is performed to control a current passage amount according to the target.

公开(公告)号：US11408059B2

公开(公告)日：2022-08-09

申请号：US16766398

申请日：2018-08-20

Applicant: JFE Steel Corporation

Inventor： Hiromi Yoshitomi ,  Yasuaki Okita ,  Masaki Koba ,  Yoshihiko Ono ,  Hiroshi Matsuda

IPC: C22C38/04 ,  C22C38/00 ,  C22C38/02 ,  C22C38/06 ,  C22C38/08 ,  C22C38/12 ,  C22C38/14 ,  C22C38/16 ,  C22C38/20 ,  C22C38/60 ,  C21D8/02 ,  C21D9/46 ,  C23G1/00 ,  C23C2/06 ,  C23C2/12 ,  C23C2/02 ,  C22C38/38 ,  C23C2/40 ,  C23C2/28 ,  C21D9/56 ,  C21D1/76 ,  C22C18/02 ,  C22C38/22 ,  C22C38/26 ,  C22C38/40 ,  C22C38/44 ,  C22C38/18 ,  C22C38/46 ,  C22C38/24 ,  C22C38/54 ,  C22C38/28 ,  C22C38/32 ,  C22C38/50 ,  C22C38/48 ,  C22C38/42 ,  C23C2/04 ,  B32B15/01 ,  C23C30/00 ,  C21D9/573 ,  B32B15/18 ,  C23C2/26 ,  B32B15/04

Abstract: A high-strength galvanized steel sheet includes a steel sheet having a steel composition having a specific component composition, a steel structure containing martensite and bainite at more than or equal to 70% (including 100%), ferrite at less than 20% (including 0%), and retained austenite at less than 5% (including 0%) in terms of area ratio, the amount of diffusible hydrogen in steel being less than or equal to 0.20 mass ppm; and a galvanizing layer provided on a surface of the steel sheet, having a content amount of Fe of 8 to 15% in mass %, and having an coating weight per one surface of 20 to 120 g/m2, wherein the amount of Mn oxides contained in the galvanizing layer is less than or equal to 0.050 g/m2, and a tensile strength is more than or equal to 1100 MPa and a yield ratio is more than or equal to 0.85.

公开(公告)号：US10946470B2

公开(公告)日：2021-03-16

申请号：US16062407

申请日：2016-12-13

Applicant: JFE STEEL CORPORATION

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

IPC: B23K11/11 ,  B23K11/16

Abstract: Provided is a resistance spot welding method that inhibits, in accordance with the degree of axis misalignment between electrodes, the occurrence of cracking in a weld regardless of the steel grade. In resistance spot welding methods according to the present invention, H (ms) is an electrode force retaining time after completion of current passage, D (mm) is an amount of axis misalignment between the electrodes, t (mm) is a total sum of sheet thicknesses of a plurality of overlapping steel sheets, T (MPa) is a tensile strength of a steel sheet having a highest tensile strength among the plurality of steel sheets, F (N) is an electrode force, and d (mm) is a tip diameter of one electrode of the pair of electrodes that has a smaller tip diameter. The electrode force retaining time H is specified to be a predetermined value or greater.

公开(公告)号：US10081074B2

公开(公告)日：2018-09-25

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 ,  B23K11/11 ,  B23K101/00 ,  B23K101/18 ,  B23K103/04

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.