Patents Assigned to JFE Steel Corporation
  • Publication number: 20220011241
    Abstract: A surface-defect detecting method of optically detecting a surface defect of a steel material, the method including: an irradiation step of irradiating an examination target part with illumination light beams from different directions by using two or more distinguishable light sources; and a detection step of detecting a surface defect in the examination target part based on the degree of overlapping of bright portions extracted from two or more images formed by reflected light beams of the illumination light beams.
    Type: Application
    Filed: November 8, 2019
    Publication date: January 13, 2022
    Applicant: JFE STEEL CORPORATION
    Inventors: Hiroaki ONO, Masami TATE
  • Publication number: 20220015196
    Abstract: A method for producing a Fe—Cr alloy comprises: rolling a slab having a chemical composition containing, by mass %, C: 0.020% or less, Si: 0.01% to 1.5%, Mn: 1.0% or less, P: 0.040% or less, S: 0.010% or less, Cr: 16.0% to 30.0%, Al: 2.0% to 6.5%, N: 0.020% or less, and Ni: 0.50% or less, with the balance being Fe and inevitable impurities to obtain a sheet material; subjecting the sheet material to siliconizing treatment by a thermal CVD method to obtain a Fe—Cr alloy having a Si content of more than 1.5 mass % and 10.0 mass % or less and satisfying: 14.0%?Si+1.15×% Al+0.35×% Cr??(1) where % Si, % Al, and % Cr indicate Si, Al, and Cr contents, by mass %, respectively in the chemical composition of the Fe—Cr alloy.
    Type: Application
    Filed: September 28, 2021
    Publication date: January 13, 2022
    Applicant: JFE STEEL CORPORATION
    Inventors: Akito Mizutani, Tatsuhiko Hiratani, Mitsuyuki Fujisawa
  • Publication number: 20220010414
    Abstract: A high-strength member having excellent delayed fracture resistance, a method for manufacturing the high-strength member, and a method for manufacturing a steel sheet for the high-strength member. The high-strength member has a bent ridge portion obtained by using a steel sheet having a tensile strength of 1470 MPa or more, an edge surface of the bent ridge portion has a residual stress of 800 MPa or less, and a longest crack among cracks that extend from the edge surface of the bent ridge portion in a bent ridge direction D1 has a length of 10 ?m or less.
    Type: Application
    Filed: September 25, 2019
    Publication date: January 13, 2022
    Applicant: JFE STEEL CORPORATION
    Inventors: Takuya HIRASHIMA, Shimpei YOSHIOKA, Shinjiro KANEKO
  • Publication number: 20220010400
    Abstract: To stably improve the magnetic flux density by utilizing induction heating and radiant heating during final annealing of a non-oriented electrical steel sheet. A method of manufacturing a non-oriented electrical steel sheet, including subjecting a slab having a predetermined chemical composition to hot rolling with or without performing hot-rolled sheet annealing, and then to cold rolling either once, or twice or more with intermediate annealing performed therebetween, and then to final annealing, where a material before final cold rolling has a recrystallization ratio of less than 80% and a {100}<011> intensity of 8 or less in a ¼ layer, and in the final annealing, an average heating rate from 600° C. to 720° C. is 50° C./s or higher, and an average heating rate from 720° C. to 760° C. is 5° C./s or higher.
    Type: Application
    Filed: November 25, 2019
    Publication date: January 13, 2022
    Applicant: JFE STEEL CORPORATION
    Inventors: Tomoyuki OKUBO, Masanori UESAKA, Yoshiaki ZAIZEN, Yoshihiko ODA
  • Publication number: 20220008938
    Abstract: A slit nozzle having a double-tube structure and a method for manufacturing a high-silicon steel strip having a small variation in Si concentration depending on the position in the width direction of the steel strip. The slit nozzle has a double-tube structure, in which a flow-control plate which closes a gap between an inner tube and an outer tube is disposed between an open end of the inner tube and an end of a delivery port, and in which an opening is formed in a plane in which the flow-control plate is disposed only in a range of the flow-control plate of 27.5° or more and 332.5° or less in terms of a central angle with respect to a reference line L1 passing through the axis of the outer tube and the central position in the width direction of the delivery port.
    Type: Application
    Filed: August 13, 2019
    Publication date: January 13, 2022
    Applicant: JFE STEEL CORPORATION
    Inventors: Teruhiko TOBE, Takashi DOI, Shinji KOSEKI
  • Publication number: 20220010397
    Abstract: A steel sheet having a specified chemical composition and a method for producing the steel sheet. The steel sheet has a microstructure comprising ferrite: 5% or less, and at least one of upper bainite, fresh martensite, tempered martensite, lower bainite, and retained ?: 95% to 100%, and retained ?: 5% to 20%. Retained ?UB has a specified area percentage S?UB, retained ?LB has a specified distribution number N?LB, and at least one of (i) fresh martensite has a specified equivalent circular grain diameter and aspect ratio and (ii) retained ? grains has a specified equivalent circular grain diameter and aspect ratio.
    Type: Application
    Filed: October 16, 2019
    Publication date: January 13, 2022
    Applicant: JFE STEEL CORPORATION
    Inventors: Yoshihiko ONO, Junya TOBATA, Hiroyuki AKIMOTO, Yoichiro MATSUI, Shinjiro KANEKO
  • Patent number: 11221272
    Abstract: A springback variation cause analysis method includes: calculating a first stress distribution in a press forming part; calculating a second stress distribution in the press forming part; calculating a difference between the second and the first stress distribution, and replacing and setting the first or the second stress distribution with the calculated stress difference distribution; calculating a first springback amount to be caused in the press forming part; changing a value of stress difference in a partial area of the press forming part in the stress difference distribution set for the press forming part; calculating a second springback amount; and analyzing a portion in the press forming part that is a cause of variation in springback amount in the press forming part due to scattering or variation in press forming conditions, based on the second springback amount and the first springback amount.
    Type: Grant
    Filed: October 19, 2018
    Date of Patent: January 11, 2022
    Assignee: JFE Steel Corporation
    Inventor: Masaki Urabe
  • Patent number: 11220732
    Abstract: Provided is a ferritic stainless steel sheet excellent in shape of weld zone and corrosion resistance of a weld zone with a material of a different kind formed by performing welding with austenitic stainless steel. A ferritic stainless steel sheet having a chemical composition containing, by mass %, C: 0.003% to 0.020%, Si: 0.01% to 1.00%, Mn: 0.01% to 0.50%, P: 0.040% or less, S: 0.010% or less, Cr: 20.0% to 24.0%, Cu: 0.20% to 0.80%, Ni: 0.01% to 0.60%, Al: 0.01% to 0.08%, N: 0.003% to 0.020%, Nb: 0.40% to 0.80%, Ti: 0.01% to 0.10%, Zr: 0.01% to 0.10%, and the balance being Fe and inevitable impurities, in which relational expression (1) below is satisfied: 3.0?Nb/(2Ti+Zr+0.5Si+5Al)?1.5??(1), here, in relational expression (1), each of the atomic symbols denotes the content (mass %) of the corresponding chemical element.
    Type: Grant
    Filed: June 15, 2017
    Date of Patent: January 11, 2022
    Assignee: JFE STEEL CORPORATION
    Inventors: Hidetaka Kawabe, Shuji Nishida, Mitsuyuki Fujisawa, Chikara Kami
  • Patent number: 11220722
    Abstract: Provided are a steel sheet having a tensile strength of 950 MPa or more and good toughness and a method for manufacturing the same. The steel sheet has a specific composition and a metallographic structure containing: a ferrite area fraction of 30% or less (including 0%), a tempered martensite area fraction of 70% or more (including 100%), and a retained austenite area fraction of 4.5% or less (including 0%), wherein the average aspect ratio of an iron based carbide, precipitated in tempered martensite grains, having a grain size in the largest 10% is 3.5 or more.
    Type: Grant
    Filed: August 29, 2017
    Date of Patent: January 11, 2022
    Assignee: JFE Steel Corporation
    Inventors: Noriaki Kohsaka, Yoshikazu Suzuki, Takeo Kikuchi, Yoshimasa Himei
  • Publication number: 20220002832
    Abstract: A production method for a high-strength steel sheet having a tensile strength TS of 780 MPa or more is provided. The production method comprises: heating a steel slab having a predetermined chemical composition; hotrolling the steel slab; coiling the hot-rolled sheet; subjecting the hot-rolled sheet to pickling treatment; holding the hot-rolled sheet in a pre-determined temperature range for predetermined time; cold rolling the hot-rolled sheet to obtain a cold-rolled sheet; subjecting the cold-rolled sheet to first annealing treatment; cooling the cold-rolled sheet at a pre-determined average cooling rate; cooling the cold-rolled sheet to room temperature; reheating the clod-rolled sheet to perform second annealing treatment; cooling the cold-rolled sheet at a first average cooling rate; cooling the cold-rolled sheet at a second average cooling rate; reheating the cold-rolled sheet to a predetermined reheating temperature range; and holding the cold-rolled sheet in the reheating temperature range.
    Type: Application
    Filed: September 17, 2021
    Publication date: January 6, 2022
    Applicant: JFE STEEL CORPORATION
    Inventors: Hidekazu MINAMI, Shinjiro KANEKO
  • Publication number: 20220001429
    Abstract: A bridle device and a method for producing a steel strip in which snaking of a steel strip that occurs during production of a high-silicon steel strip is suppressed. The bridle device includes a pair of upper and lower rotatable endless belts or a pair of upper and lower rotatable caterpillars configured to pinch a steel strip. The bridle device is movable or swingable in a steel strip width direction by using a steering mechanism. The bridle device further includes a rolling reduction mechanism configured to perform rolling reduction on a pinched portion of the steel strip by using the pair of upper and lower endless belts or the pair of upper and lower caterpillars. The steering mechanism moves or swings the bridle device in the steel strip width direction, and the rolling reduction mechanism performs rolling reduction on one of end portions in the steel strip width direction.
    Type: Application
    Filed: October 16, 2019
    Publication date: January 6, 2022
    Applicant: JFE STEEL CORPORATION
    Inventors: Takashi DOI, Shoji KASAI, Teruhiko TOBE
  • Publication number: 20220003500
    Abstract: A gas injection nozzle refractory with one or more gas injection small metal tubes buried therein has improved durability. The gas injection nozzle refractory includes a MgO-C central refractory with a small metal tube buried therein, and a MgO-C peripheral refractory surrounding the central refractory. The central refractory on a plane of the gas injection nozzle refractory has an external shape of a circle with a radius in the range of R+10 to R+150 mm concentric with a virtual circle with a minimum radius surrounding all buried small metal tubes, R mm being a radius of the virtual circle.
    Type: Application
    Filed: September 19, 2019
    Publication date: January 6, 2022
    Applicants: JFE STEEL CORPORATION, SHINAGAWA REFRACTORIES CO., LTD.
    Inventors: Seiji HOSOHARA, Atsuhisa IIDA, Atsushi TORIGOE, Ryoma FUJIYOSHI
  • Publication number: 20220002827
    Abstract: A high-strength steel sheet having high delayed fracture resistance and a method for manufacturing the high-strength steel sheet. The high-strength steel sheet has a specified chemical composition. Relative to the whole microstructure of the steel sheet, the total area fraction of at least one of (i) bainite containing carbide grains having an average grain size of 50 nm or less and (ii) martensite containing carbide grains having an average grain size of 50 nm or less is 90% or more. The average number of inclusions having an average grain size of 5 ?m or more that are present in a section of the steel sheet perpendicular to a rolling direction is 5.0/mm2 or less.
    Type: Application
    Filed: September 25, 2019
    Publication date: January 6, 2022
    Applicant: JFE STEEL CORPORATION
    Inventors: Takuya HIRASHIMA, Shimpei YOSHIOKA, Shinjiro KANEKO
  • Patent number: 11214847
    Abstract: A high-strength hot-rolled steel sheet for an electric resistance welded steel pipe has decreased variations in in-plane material properties, high strength, and excellent ductility. The high-strength hot-rolled steel sheet has a composition containing, in mass %, C: 0.10 to 0.18%, Si: 0.1 to 0.5%, Mn: 0.8 to 2.0%, P: 0.001 to 0.020%, S: 0.005% or less, Al: 0.001 to 0.1%, Cr: 0.4 to 1.0%, Cu: 0.1 to 0.5%, Ni: 0.01 to 0.4%, Nb: 0.01 to 0.07%, N: 0.008% or less, and further Mo: 0.5% or less and/or V: 0.1% or less so that Moeq defined as Moeq=Mo+0.36Cr+0.77Mn+0.07Ni is 1.4 to 2.2, and Mo and V are contained to satisfy 0.05?Mo+V?0.5; and has a microstructure containing, in volume fraction, 80% or more of a bainite phase as a primary phase and 4 to 20% of a martensite phase and a retained austenite phase in total as a secondary phase, where the bainite phase has an average grain size of 1 to 10 ?m.
    Type: Grant
    Filed: January 23, 2017
    Date of Patent: January 4, 2022
    Assignee: JFE Steel Corporation
    Inventors: Hiroshi Nakata, Motohiko Urabe, Shuji Kawamura
  • Publication number: 20210404030
    Abstract: Disclosed is a non-heat-treated steel that has low deformation resistance during cold forging in bolt head forming and excellent product yield, and that can be manufactured without the need to perform heat treatment for controlling strength variation. The disclosed steel has a chemical composition containing C: 0.18-0.24%, Si: 0.10-0.22%, Mn: 0.60-1.00%, Al: 0.010-0.050%, Cr: 0.65-0.95%, Ti: 0.010-0.050%, B: 0.0015-0.0050%, N: 0.0050-0.0100%, P: 0.025% or less inclusive of 0, S: 0.025% or less inclusive of 0, Cu: 0.20% or less inclusive of 0, and Ni: 0.30% or less inclusive of 0, in a range satisfying: 0.45?C+Si/24+Mn/6+Ni/40+Cr/5?0.60 and N?0.519A1+0.292Ti, with the balance being Fe and inevitable impurities; and a microstructure in which bainite is present in an area ratio of 95% or more, where the microstructure contains prior austenite grains with a grain size number of 6 or more, and strength variation is 100 MPa or less.
    Type: Application
    Filed: June 25, 2019
    Publication date: December 30, 2021
    Applicant: JFE STEEL CORPORATION
    Inventor: Masafumi TADA
  • Publication number: 20210407738
    Abstract: The present invention provides a novel method for producing a laminate to be used as a light-transmissive electrode layer and an N-type semiconductor layer of a wet or solid-state dye-sensitized solar cell comprising a light-transmissive electrode layer, an N-type semiconductor layer, a P-type semiconductor layer, and a facing electrode in this order. In said method, a member to be used as the light-transmissive electrode layer is cathode-polarized in a treatment solution containing a Ti component so as to form a titanium oxide layer to be used as the N-type semiconductor layer on said member.
    Type: Application
    Filed: December 9, 2019
    Publication date: December 30, 2021
    Applicant: JFE Steel Corporation
    Inventors: Mikito SUTO, Hiroyuki MASUOKA, Akira MATSUZAKI
  • Publication number: 20210404992
    Abstract: An elastic matrix determination method for a laminated iron core, which can optimally determine a shear modulus in two planes including a laminating direction of the laminated iron core included in an elastic matrix in a constitutive equation representing a stress-strain relationship used for vibration analysis, and also provided is a vibration analysis method. When performing a vibration analysis of a laminated iron core formed by laminating steel sheets using a constitutive equation representing a stress-strain relationship in a matrix representation, a shear modulus in two planes including a laminating direction of the laminated iron core included in an elastic matrix in the constitutive equation is determined depending on an average tightening pressure in the laminating direction of the laminated iron core.
    Type: Application
    Filed: September 4, 2019
    Publication date: December 30, 2021
    Applicant: JFE STEEL CORPORATION
    Inventor: Misao NAMIKAWA
  • Patent number: 11208704
    Abstract: A high-strength cold-rolled steel sheet has a component composition containing, on a percent by mass basis, C: 0.12% or more and 0.25% or less, Si: less than 0.5%, Mn: 2.0% or more and 3.0% or less, P: 0.05% or less, S: 0.005% or less, Al: 0.01% or more and 0.10% or less, and N: 0.010% or less, the balance being Fe and incidental impurities, the total area percentage of martensite and tempered martensite satisfying 20% or more and 90% or less, the area percentage of ferrite satisfying 10% or less, the area percentage of bainite satisfying 10% or more and 80% or less, the area percentage of a martensite-austenite constituent in the bainite being 1% or more and 10% or less, the area percentage of cementite having an average grain size of 1 ?m or less in the bainite being 0.1% or more and 5.0% or less.
    Type: Grant
    Filed: April 19, 2017
    Date of Patent: December 28, 2021
    Assignee: JFE Steel Corporation
    Inventors: Takuya Hirashima, Hiromi Yoshitomi
  • Patent number: 11208709
    Abstract: Provided are a high-strength steel sheet having a yield strength of 550 MPa or higher and having a small amount of springback and width-direction uniformity in material properties as well as a manufacturing method therefor. The high-strength steel sheet has a yield strength (YP) of 550 MPa or higher and has a specific component composition and a microstructure containing a ferrite phase, 40 to 70% of a martensite phase in area ratio, and 5 to 30% of a bainite phase in area ratio, where: an average grain size of the martensite phase is 2 to 8 ?m and an average grain size of the ferrite phase is 11 ?m or less on a cross-section in the thickness direction and in a direction orthogonal to a rolling direction; and the average grain size of the ferrite phase is 3.0 times or less the average grain size of martensite.
    Type: Grant
    Filed: February 21, 2018
    Date of Patent: December 28, 2021
    Assignee: JFE STEEL CORPORATION
    Inventors: Lingling Yang, Noriaki Kohsaka, Tatsuya Nakagaito
  • Patent number: 11208712
    Abstract: There is provided a galvanized steel sheet more highly excellent in terms of punchability. The steel sheet has a specified chemical composition and a microstructure including a ferrite phase and a tempered bainite phase in a total amount of 95% or more in terms of area ratio, in which the average grain diameter of the microstructure is 5.0 ?m or less, the amount of Fe precipitated is 0.10 mass % or more, the amount of Ti, Nb, and V precipitated in the form of precipitates having a grain diameter of less than 20 nm is 0.025 mass % or more in terms of precipitate C equivalent, and half or more of precipitates having a grain diameter of less than 20 nm are formed at random.
    Type: Grant
    Filed: February 1, 2018
    Date of Patent: December 28, 2021
    Assignee: JFE STEEL CORPORATION
    Inventors: Taro Kizu, Noriaki Moriyasu, Shigeyuki Nabeshima, Kazunori Tahara, Kana Sasaki