Patents Assigned to JFE Steel Corporation
  • GRAIN-ORIENTED ELECTRICAL STEEL SHEET AND PRODUCTION METHOD THEREFOR
    Publication number: 20240052447
    Abstract: Provided is a grain-oriented electrical steel sheet that can benefit from the iron loss improving effect by groove formation while effectively suppressing a decrease in magnetic flux density. A grain-oriented electrical steel sheet comprises predetermined linear grooves, wherein in each linear groove, a proportion of predetermined flat portions to an entire length of the linear groove is 30% or more and 90% or less, the number of flat portions each of which is continuous for a predetermined length is 10 or more per 100 cm2 surface area, and a ratio of ten-point average roughness Rzjis to average depth D is 0.1 or more and 1 or less.
    Type: Application
    Filed: September 22, 2021
    Publication date: February 15, 2024
    Applicant: JFE STEEL CORPORATION
    Inventors: Masanori ODACHI, Takeshi OMURA, Yoshihisa ICHIHARA
  • HIGH STRENGTH STEEL SHEET, IMPACT ABSORBING MEMBER, AND METHOD FOR MANUFACTURING HIGH STRENGTH STEEL SHEET
    Publication number: 20240052449
    Abstract: A high strength steel sheet has a yield-point elongation of 1% or greater and a tensile strength of 980 MPa or greater. The high strength steel sheet has a specific chemical composition and microstructure. A ratio of retained austenite grains adjoining a retained austenite grain having a different crystal orientation to total retained austenite grains is 0.60 or greater, the ferrite has an average grain size of 5.0 ?m or less, and the retained austenite has an average grain size of 2.0 ?m or less. A value obtained by dividing a volume fraction V?a by a volume fraction V?b is 0.40 or greater, where the volume fraction V?a is a volume fraction of retained austenite in a fractured portion of a tensile test specimen after a warm tensile test at 150° C., and the volume fraction V?b is a volume fraction of retained austenite before the warm tensile test at 150° C.
    Type: Application
    Filed: September 25, 2020
    Publication date: February 15, 2024
    Applicant: JFE Steel Corporation
    Inventors: Yoshiyasu Kawasaki, Yuki Toji, Muneka Iwasawa, Takayuki Futatsuka, Kentaro Sato
  • METHOD OF MANUFACTURING GRAIN-ORIENTED ELECTRICAL STEEL SHEET AND ROLLING APPARATUS FOR MANUFACTURING ELECTRICAL STEEL SHEET
    Publication number: 20240052448
    Abstract: Provided is a method of manufacturing a grain-oriented electrical steel sheet, with which a grain-oriented electrical steel sheet with low iron loss and little variation in iron loss can be stably manufactured by a tandem mill. The method includes subjecting a steel material to hot rolling to obtain a hot-rolled sheet, subjecting the hot-rolled sheet to cold rolling once or twice or more with intermediate annealing performed therebetween to obtain a cold-rolled sheet with a final sheet thickness, and then subjecting the cold-rolled sheet to decarburization annealing and then to secondary recrystallization annealing, wherein final cold rolling is performed by a tandem mill, and in the final cold rolling, the hot-rolled sheet is heated to a temperature range of 70° C. or higher and 200° C. or lower, then cooled to 60° C. or lower, and then introduced into a first pass of the tandem mill.
    Type: Application
    Filed: January 26, 2022
    Publication date: February 15, 2024
    Applicant: JFE STEEL CORPORATION
    Inventors: Yusuke SHIMOYAMA, Yukihiro SHINGAKI, Hiroi YAMAGUCHI
  • STEEL SHEET, MEMBER, AND METHODS FOR MANUFACTURING THE SAME
    Publication number: 20240052466
    Abstract: Provided are a steel sheet and a member, having high strength and high delayed fracture resistance, and methods for manufacturing the steel sheet and the member. The steel sheet has a specific chemical composition and a microstructure in which the area fraction of martensite is 95% to 100%, with the balance being one or more of bainite, ferrite, and retained austenite. In the steel sheet, prior-austenite grains have an average grain size of 18 ?m or less, 90 mass % or more of the total content of Nb and Ti contained is present as a carbonitride having an equivalent circular diameter of 100 nm or more, and a Nb carbonitride and a Ti carbonitride, having an equivalent circular diameter of 1.0 ?m or more, are present at a rate of 800 pieces/mm2 or less in total. The steel sheet has a tensile strength of 1310 MPa or more.
    Type: Application
    Filed: December 24, 2021
    Publication date: February 15, 2024
    Applicant: JFE Steel Corporation
    Inventors: Taiyo Asakawa, Shimpei Yoshioka, Shinjiro Kaneko
  • HIGH STRENGTH STEEL SHEET, IMPACT ABSORBING MEMBER, AND METHOD FOR MANUFACTURING HIGH STRENGTH STEEL SHEET
    Publication number: 20240052464
    Abstract: A high strength steel sheet has a yield-point elongation of 1.0% or greater and a tensile strength of 980 MPa or greater. The high strength steel sheet has a specific chemical composition and microstructure. The ferrite has an average grain size of 5.0 ?m or less, the retained austenite has an average grain size of 2.0 ?m or less, a value obtained by dividing a Mn content of the retained austenite by a Mn content of steel is 1.50 or greater, 15% or more of all retained austenite grains in the retained austenite have an aspect ratio of 3.0 or greater, and 15% or more of all the retained austenite grains in the retained austenite have an aspect ratio of less than 2.0.
    Type: Application
    Filed: September 25, 2020
    Publication date: February 15, 2024
    Applicant: JFE Steel Corporation
    Inventors: Yoshiyasu Kawasaki, Muneka Iwasawa, Yuki Toji, Yoshimasa Funakawa
  • METHOD FOR CHARGING RAW MATERIALS INTO BLAST FURNACE
    Publication number: 20240052439
    Abstract: A method for charging raw materials into a blast furnace is as follows. The blast furnace includes a bell-less charging device that includes a plurality of main hoppers and an auxiliary hopper. The auxiliary hopper has a smaller capacity than the main hoppers. The method includes discharging ore charged in at least one of the plurality of main hoppers, and then sequentially charging the ore from a furnace wall side toward a furnace center side by using a rotating chute. The discharging of low-reactivity ore charged in the auxiliary hopper is started simultaneously with a start of charging of the ore or at a point in time after the start of the charging; and then, the low-reactivity ore is charged together with the ore from the rotating chute. The charging of the low-reactivity ore is stopped at least before a point in time at which charging of 56 mass % of the ore is completed.
    Type: Application
    Filed: October 25, 2023
    Publication date: February 15, 2024
    Applicant: JFE Steel Corporation
    Inventors: Kazuhira Ichikawa, Yasushi Ogasawara, Takeshi Sato
  • Metal structure evaluator for rolled steel sheets, method for evaluating metal structure of rolled steel sheet, production facility of steel product, method for manufacturing steel product, and method of quality management of steel product
    Patent number: 11898985
    Abstract: A metal structure evaluator for rolled steel sheets includes: a magnetic property measuring unit configured to measure a magnetic property of an evaluation target point in at least two or more different magnetization directions by performing, in the at least two or more different magnetization directions, processing of: applying a magnetic field on a surface of a rolled steel sheet in one direction; and measuring a magnetic property of the evaluation target point on the surface of the rolled steel sheet; and a determination unit configured to determine a metal structure of the evaluation target point based on the magnetic property measured by the magnetic property measuring unit.
    Type: Grant
    Filed: April 17, 2020
    Date of Patent: February 13, 2024
    Assignee: JFE STEEL CORPORATION
    Inventors: Takafumi Ozeki, Yutaka Matsui, Kenji Adachi, Junji Shimamura
  • High-strength steel sheet and method for manufacturing same
    Patent number: 11898230
    Abstract: A high-strength steel sheet according to the present invention includes a specific chemical composition, and a steel structure in which a total area fraction of martensite and bainite in a position of ¼ of a sheet thickness is 95% or more and 100% or less, the balance in a case where the total area fraction is not 100% contains retained austenite, and an area fraction of ferrite in a region extending up to 10 ?m in a sheet thickness direction from a surface is 10% or more and 40% or less, in which a tensile strength is 1320 MPa or more, and a Vickers hardness in a position of 15 ?m in the sheet thickness direction from the surface satisfies a specified formula.
    Type: Grant
    Filed: June 10, 2019
    Date of Patent: February 13, 2024
    Assignee: JFE Steel Corporation
    Inventors: Shimpei Yoshioka, Yoshihiko Ono
  • CONTINUOUS CASTING METHOD OF STEEL
    Publication number: 20240042515
    Abstract: A continuous casting method of steel of continuously casting a slab by using a vertical liquid bending type continuous casting machine. The method includes, while performing continuous casting by using an in-mold electromagnetic stirring device, applying an alternating-current moving magnetic field that moves in a width direction of a mold to molten steel inside the mold, inducing a swirling flow in the molten steel, and stirring the molten steel. A travel speed of the alternating-current moving magnetic field calculated by a specified formula is in a range of 0.20 to 1.50 m/s.
    Type: Application
    Filed: November 29, 2021
    Publication date: February 8, 2024
    Applicant: JFE STEEL CORPORATION
    Inventors: Naoya SHIBUTA, Satoshi OYAMA, Yoshiyuki TANAKA, Akitoshi MATSUI
  • SHAPE CHANGE PREDICTION METHOD OF PRESS FORMED PART
    Publication number: 20240042505
    Abstract: A shape change prediction method of a press formed part predicts a shape change in which an end side in a longitudinal direction is twisted due to stress relaxation with a lapse of time after springback at a moment of die release from a tool of press forming with respect to the press formed part having a U-shaped cross-sectional shape including a top portion and side wall portions, and includes: acquiring a shape and a residual stress of the press formed part immediately after the springback by a springback analysis of the press formed part; setting a value of stress relaxed and reduced compared to the residual stress immediately after the springback for at least one of the side wall portions; and acquiring a shape with which moment of force is balanced for the press formed part in which the value of the relaxed and reduced stress is set.
    Type: Application
    Filed: August 6, 2021
    Publication date: February 8, 2024
    Applicant: JFE STEEL CORPORATION
    Inventors: Yusuke FUJII, Masaki URABE, Shunsuke TOBITA
  • METHOD OF EVALUATING CENTRAL SEGREGATION IN STEEL
    Publication number: 20240044822
    Abstract: A method of evaluating central segregation in steel with excellent correlation with HIC susceptibility is provided. A method of evaluating central segregation in steel includes: taking a sample from a steel, the sample having a cross section including a central segregation area; measuring an area ratio of an inclusion containing a segregation metal element in a region to be measured including the central segregation area in the cross section; and evaluating central segregation in the steel based on the area ratio measured.
    Type: Application
    Filed: September 6, 2021
    Publication date: February 8, 2024
    Applicant: JFE STEEL CORPORATION
    Inventors: Tomoharu ISHIDA, Seiya SUGAWARA, Kenji TSUZUMI
  • DELAYED FRACTURE CHARACTERISTIC EVALUATION METHOD AND PROGRAM
    Publication number: 20240044760
    Abstract: To further enhance the evaluation accuracy of a delayed fracture. Focusing on the fact that a calculated stress value serving as the reference for the occurrence of the delayed fracture changes depending on analysis conditions of a forming analysis, a value obtained by changing a stress value serving as the reference for the occurrence of the delayed fracture according to the analysis conditions for analyzing an intended formed article (article for practical use) is used as the reference for evaluating the delayed fracture. For example, analysis conditions of a forming analysis in an evaluation test of the delayed fracture are matched with analysis conditions of a forming analysis of an article for practical use represented by an actual automobile component.
    Type: Application
    Filed: July 29, 2021
    Publication date: February 8, 2024
    Applicant: JFE STEEL CORPORATION
    Inventors: Yuichi MATSUKI, Toyohisa SHINMIYA, Kinya NAKAGAWA, Yuji YAMASAKI
  • POWDER FOR ANNEALING SEPARATOR AND PRODUCTION METHOD FOR GRAIN-ORIENTED ELECTRICAL STEEL SHEET USING SAME
    Publication number: 20240043950
    Abstract: An annealing separator, by being applied to a steel sheet, enables retention of a good shape of a coil after annealing obtained by winding the steel sheet with the annealing separator applied thereto into a coil which is then annealed at a high temperature exceeding 1000° C. A powder used as the annealing separator: contains magnesium oxide as a main component and B: 0.020 mass % or more and 0.200 mass % or less, SO3: 0.030 mass % or more and 2.000 mass % or less, and P2O3: 0.050 mass % or more and 1.000 mass % or less; and contains 0.2 mass % or more and 5.0 mass % or less of particles having a particle size of more than 45 ?m and 75 ?m or less. The particles having this particle size contain (boron) B: 0.002 mass % or more and less than 0.020 mass %, SO3: less than 0.030 mass %, and P2O3: less than 0.050 mass %.
    Type: Application
    Filed: March 14, 2022
    Publication date: February 8, 2024
    Applicant: JFE STEEL CORPORATION
    Inventors: Takashi TERASHIMA, Karin SHIROYANAGI
  • Duplex stainless clad steel plate and method of producing same
    Patent number: 11891675
    Abstract: Disclosed is a duplex stainless clad steel plate in which a duplex stainless steel plate as a cladding metal is bonded or joined to one or both surfaces of a base steel plate, in which the base steel plate comprises a predetermined chemical composition such that Nb/N is 3.0 or more and Ceq is 0.35 to 0.45, and the duplex stainless steel plate comprises: a predetermined chemical composition such that PI is 34.0 to 43.0; and a microstructure containing a ferrite phase in an area fraction of 35% to 65%, and in the microstructure, an amount of precipitated Cr is 2.00% or less and an amount of precipitated Mo is 0.50% or less.
    Type: Grant
    Filed: March 28, 2019
    Date of Patent: February 6, 2024
    Assignee: JFE STEEL CORPORATION
    Inventors: Yota Kuronuma, Hirofumi Ohtsubo, Tomoyuki Yokota
  • Control method for continuous casting machine, control device for continuous casting machine, and manufacturing method for casting
    Patent number: 11890671
    Abstract: A control method for a continuous casting machine, includes: estimating, by on-line real-time system, a flow state of molten steel in a mold by using an operation condition of a continuous casting machine and temperature data on the molten steel in the mold; calculating, by on-line real-time system, a molten steel flow index based on the estimated flow state of the molten steel, the molten steel flow index being a factor of mixing of an impurity into a casting inside the mold; and controlling the operation condition of the continuous casting machine such that the calculated molten steel flow index is within an appropriate range.
    Type: Grant
    Filed: February 6, 2020
    Date of Patent: February 6, 2024
    Assignee: JFE STEEL CORPORATION
    Inventors: Ryosuke Masuda, Yoshinari Hashimoto, Akitoshi Matsui, Shugo Morita, Tatsuro Hayashida, Taiga Koriyama, Ryo Morishita
  • Grain-oriented electrical steel sheet, iron core of transformer, transformer, and method for reducing noise of transformer
    Patent number: 11894167
    Abstract: A grain-oriented electrical steel sheet having an insulating film disposed on a surface thereon. The insulating film having a chemical composition comprising Si, P, O, and at least one selected from the group consisting of Mg, Ca, Ba, Sr, Zn, Al, Mn, and Co. The insulating film has a crystallinity in a range of 20% or more, and a minimum tension provided to the steel sheet by the insulating film at a temperature in a range of 100° C. to 200° C. is 10 MPa or more.
    Type: Grant
    Filed: November 17, 2017
    Date of Patent: February 6, 2024
    Assignee: JFE STEEL CORPORATION
    Inventors: Takashi Terashima, Makoto Watanabe, Toshito Takamiya, Tomoyuki Okubo
  • THREADED STEEL PIPE OR TUBE AND PRODUCTION METHOD THEREFOR
    Publication number: 20240035593
    Abstract: To alleviate stress exerted on a thread portion of a threaded steel pipe or tube during use to prevent fatigue fracture, there is provided a threaded steel pipe or tube having a female thread portion on an inner peripheral surface of at least one end, wherein a maximum value of residual compressive stress at a position of 0.4 mm in a depth direction from a thread bottom of the female thread portion is 100 MPa or more and less than or equal to tensile strength of a material of the threaded steel pipe or tube.
    Type: Application
    Filed: November 2, 2021
    Publication date: February 1, 2024
    Applicant: JFE STEEL CORPORATION
    Inventors: Hiroshi OKANO, Kazuki MATSUBARA, Shusaku TAKAGI, Nobuyuki ISHIKAWA
  • METHOD FOR PRODUCING MOLTEN IRON USING ELECTRIC FURNACE
    Publication number: 20240035102
    Abstract: An electric furnace with energy utilization efficiency at a low cost. In an electric furnace, a preheating chamber 2 with a melting chamber 1 is used to preheat iron scrap x, an exhaust gas generated in melting chamber 1 is passed through preheating chamber 2 filled with the iron scrap x to preheat the iron scrap x, the iron scrap x descends in the preheating chamber 2 to be supplied into melting chamber 1, and the iron scrap x is melted to obtain molten iron m. The iron scrap x is charged into preheating chamber 2 so that bulk density is not less than 0.50 t/m3 and less than 1.00 t/m3 and an iron scrap filling ratio HSC/HSF in the preheating chamber 2 is 0.5 to 0.8. A carbonaceous material is used for melting the iron scrap x, and oxygen and the carbonaceous material are blown into the melting chamber.
    Type: Application
    Filed: June 22, 2020
    Publication date: February 1, 2024
    Applicant: JFE STEEL CORPORATION
    Inventors: Yoshihiro MIWA, Koichi TSUTSUMI, Ikuhiro SUMI
  • METHOD OF DETECTING CHATTERING IN COLD ROLLING MILL, CHATTERING DETECTING DEVICE FOR COLD ROLLING MILL, COLD ROLLING METHOD, COLD ROLLING MILL, AND METHOD OF MANUFACTURING STEEL SHEET
    Publication number: 20240033797
    Abstract: A method of detecting chattering in a cold rolling mill, the method includes: a step of predicting occurrence of chattering during rolling of a material to be rolled, by inputting second multidimensional data to a prediction model, the second multidimensional data having been generated based on condition data corresponding to array data related to the material to be rolled, and the prediction model having been trained with an explanatory variable and an objective variable, the explanatory variable being first multidimensional data generated based on one-dimensional array data representing a past rolling record of rolling of rolled materials by means of a cold rolling mill, and the objective variable being a past record of occurrence of chattering corresponding to the past rolling record.
    Type: Application
    Filed: October 29, 2021
    Publication date: February 1, 2024
    Applicant: JFE Steel Corporation
    Inventors: Noriki Fujita, Takuya Kitamura, Tetsuya Arakawa
  • COLD ROLLING METHOD, COLD ROLLING EQUIPMENT, AND COLD-ROLLED STEEL SHEET MANUFACTURING METHOD
    Publication number: 20240033795
    Abstract: A cold rolling method, cold rolling equipment, and a cold-rolled steel sheet manufacturing method capable of preventing sheet breakage by sufficiently suppressing occurrence of an edge crack of a material to be rolled during cold rolling. In the cold rolling method, a rolling mill including a plurality of stands to cold-rolls a material to be rolled. An N-th stand (N is a natural number equal to or greater than 2) arranged in an N-th position from an upstream side of the material to be rolled in a transfer direction among the plurality of stands, includes a tapered work roll having a taper formed on an end portion of a roll having a uniform diameter. The N-th stand rolls the material to be rolled with a linear load of 0.8 t/mm or more.
    Type: Application
    Filed: September 7, 2021
    Publication date: February 1, 2024
    Applicant: JFE STEEL CORPORATION
    Inventors: Yoshiki IKOMA, Yoshimitsu HARADA, Yu NAGAI, Yukihiro MATSUBARA, Noriki FUJITA