Patents Assigned to JFE Steel Corporation
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Publication number: 20240133003Abstract: The method includes slab-heating a steel slab to a temperature of higher than a ?-phase precipitation temperature and 1380° C. or lower, subjecting the steel slab to rough rolling including at least two passes of rolling at a predetermined temperature with an introduced sheet thickness true strain ?t of 0.50 or more and to finish rolling with a rolling finish temperature of 900° C. or higher to obtain a hot-rolled sheet, cooling the sheet for 1 second or longer at a cooling rate of 70° C./s or higher within 2 seconds after finish rolling, coiling the sheet at a coiling temperature of 600° C. or lower, performing hot-rolled sheet annealing for soaking at a predetermined soaking temperature, and then performing cold rolling, primary recrystallization annealing, and secondary recrystallization annealing.Type: ApplicationFiled: March 2, 2022Publication date: April 25, 2024Applicant: JFE STEEL CORPORATIONInventors: Shigehiro TAKAJO, Hiroi YAMAGUCHI
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Publication number: 20240136095Abstract: The method includes slab-heating a steel slab to a temperature of higher than a ?-phase precipitation temperature and 1380° C. or lower, subjecting the steel slab to rough rolling including at least two passes of rolling at a predetermined temperature with an introduced sheet thickness true strain ?t of 0.50 or more and to finish rolling with a rolling finish temperature of 900° C. or higher to obtain a hot-rolled sheet, cooling the hot-rolled sheet for 1 second or longer at a cooling rate of 70° C./s or higher within 2 seconds after finish rolling, coiling the sheet at a coiling temperature of 600° C. or lower, performing hot-rolled sheet annealing for soaking at a predetermined soaking temperature, and then performing cold rolling, primary recrystallization annealing, and secondary recrystallization annealing.Type: ApplicationFiled: March 2, 2022Publication date: April 25, 2024Applicant: JFE STEEL CORPORATIONInventors: Shigehiro TAKAJO, Hiroi YAMAGUCHI
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Publication number: 20240132987Abstract: A steel sheet has a certain chemical composition and a steel microstructure containing, in area fraction, martensite: 40% or more and 78% or less, bainite: 20% or more and 58% or less, and retained austenite: 2% or more. Carbides in tempered martensite in the martensite have an average particle size of 0.40 ?m or less, an average amount of C in the retained austenite is 0.5% by mass or more, a Si concentration in a region within 100 ?m in a thickness direction from a surface of the steel sheet is 1.3% by mass or less, and a tensile strength is 1,470 MPa or more.Type: ApplicationFiled: January 28, 2022Publication date: April 25, 2024Applicant: JFE Steel CorporationInventors: Katsuya Hata, Shimpei Yoshioka, Shinjiro Kaneko
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Publication number: 20240132982Abstract: A residual molten material amount detection method and detection apparatus that can detect a residual amount of molten material in a vertical furnace and a method for operating a vertical furnace by using the detection method. The residual molten material amount detection method detects a residual amount of molten material remaining in a bottom portion of a vertical furnace after end of discharge of the molten material. The method includes detecting the residual amount of the molten material by using a difference between a production speed of the molten material and a discharge speed of the molten material that is calculated by using a discharge acceleration, a discharge period, and an initial discharge speed of the discharge of the molten material through a taphole.Type: ApplicationFiled: January 13, 2022Publication date: April 25, 2024Applicant: JFE STEEL CORPORATIONInventors: Yuki KAWASHIRI, Tetsuya YAMAMOTO, Taihei NOUCHI, Kazuhira ICHIKAWA
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Publication number: 20240132986Abstract: A steel sheet has a chemical composition containing, by mass %, C: 0.20% or more and 0.40% or less, Si: more than 1.0% and 3.0% or less, Mn: 1.5% or more and 3.5% or less, P: 0.002% or more and 0.010% or less, S: 0.0002% or more and 0.0020% or less, sol. Al: 0.40% or less (not including 0%), and N: 0.0100% or less, with the balance being Fe and incidental impurities; and a steel microstructure containing, in area fraction, tempered martensite: 45% or more and 83% or less, bainite: 15% or more and 53% or less, and retained austenite: 2% or more. Carbides in the tempered martensite have an average particle size of 0.40 ?m or less, an average amount of C in the retained austenite is 0.5% by mass or more, and a tensile strength is 1,470 MPa or more.Type: ApplicationFiled: January 28, 2022Publication date: April 25, 2024Applicant: JFE Steel CorporationInventors: Katsuya Hata, Shimpei Yoshioka, Shinjiro Kaneko
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Publication number: 20240131632Abstract: A TIG welded joint in a high-Mn content steel material that can be formed with reduced occurrence of hot cracking during the welding process and has high strength and excellent cryogenic impact toughness. In the TIG welded joint, the high-Mn content steel material has a chemical composition including, by mass %, C: 0.10 to 0.80%, Si: 0.05 to 1.00%, Mn: 18.0 to 30.0%, P: 0.030% or less, S: 0.0070% or less, Al: 0.010 to 0.070%, Cr: 2.5 to 7.0%, N: 0.0050 to 0.0500%, and O: 0.0050% or less, the balance being Fe and incidental impurities, and a weld metal has a chemical composition including C: 0.10 to 0.80%, Si: 0.05 to 1.00%, Mn: 15.0 to 30.0%, P: 0.030% or less, S: 0.030% or less, Al: 0.100% or less, Cr: 6.0 to 14.0%, and N: 0.100% or less, the balance being Fe and incidental impurities.Type: ApplicationFiled: February 28, 2022Publication date: April 25, 2024Applicant: JFE STEEL CORPORATIONInventors: Kazufumi WATANABE, Atsushi TAKADA, Akiyoshi ANDO, Takatoshi OKABE, Keiji UEDA
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Patent number: 11965223Abstract: A thin steel sheet has a steel structure which has a ferrite area fraction of 30% or less, a bainite area fraction of 5% or less, a martensite and tempered martensite area fraction of 70% or more, and a retained austenite area fraction of 2.0% or less and in which the ratio of the dislocation density in the range of 0 ?m to 20 ?m from a surface of the steel sheet to the dislocation density of a through-thickness central portion of the steel sheet is 90% to 110% and the average of the top 10% of the sizes of cementite grains located in a depth of up to 100 ?m from a surface of the steel sheet is 300 nm or less. The maximum camber of the steel sheet sheared to a length of 1 m in a longitudinal direction of the steel sheet is 15 mm or less.Type: GrantFiled: July 18, 2019Date of Patent: April 23, 2024Assignee: JFE Steel CorporationInventors: Noriaki Kohsaka, Soshi Yoshimoto, Tomohiro Hashimukai, Takuya Hirashima
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Patent number: 11965222Abstract: A method of producing a hot-rolled steel sheet and a method for producing a cold-rolled full hard steel sheet are provided. The methods comprising heating a steel slab having a composition containing, in terms of mass %, C: 0.010% or more and 0.150% or less, Si: 0.20% or less, Mn: 1.00% or less, P: 0.100% or less, S: 0.0500% or less, Al: 0.001% or more and 0.100% or less, N: 0.0100% or less, and the balance being Fe and unavoidable impurities, in which 0.002%?[% P]+[% S]?0.070% ([% M] denotes a content (mass %) of M element in steel) is satisfied.Type: GrantFiled: January 26, 2021Date of Patent: April 23, 2024Assignee: JFE Steel CorporationInventors: Hidekazu Minami, Yoshimasa Funakawa
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Patent number: 11965858Abstract: 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: GrantFiled: September 4, 2019Date of Patent: April 23, 2024Assignee: JFE STEEL CORPORATIONInventor: Misao Namikawa
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Patent number: 11966669Abstract: A molten metal component estimation device including: an input device configured to receive measurement information about a refining facility including measurement results regarding an optical characteristic; a model database that stores model expressions and model parameters, regarding a blowing process reaction, including a model expression and model parameters representing a relation between the oxygen efficiency in decarburization and a carbon concentration in a molten metal in the refining facility; and a processor configured to: estimate component concentrations of the molten metal including the carbon concentration in the molten metal by using the measurement information, the model expressions and the model parameters; estimate the carbon concentration in the molten metal based on the measurement results; and determine the model expression and the model parameters to be used when estimating the component concentrations of the molten metal, based on the estimation result of the carbon concentration in tType: GrantFiled: April 3, 2019Date of Patent: April 23, 2024Assignee: JFE STEEL CORPORATIONInventors: Hiroto Kase, Shinji Tomiyama, Yukio Takahashi, Shota Amano, Toshifumi Kodama
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Publication number: 20240123531Abstract: A method for producing a flared or lap joint including a steel sheet and an aluminum-based sheet material through brazing, wherein a preceding laser beam irradiates ahead of a steel sheet joining position and the aluminum-based sheet material in the joining direction to preheat a joining position, an electrically-heated aluminum-based filler wire feeds to the joining position, a following laser beam is irradiated behind the filler wire so the wire melts performin brazing, and the filler wire is fed with a tilt ranging from 0°?D?19° to a front or rear side in the joining direction with respect to a line passing through a groove center of the flared joint and is perpendicular to the joining direction, so that a flared joint or lap joint including a steel sheet and aluminum-based sheet material is produced without appearance defects of a bead and with a sufficient joint strength.Type: ApplicationFiled: February 22, 2022Publication date: April 18, 2024Applicant: JFE STEEL CORPORATIONInventors: Koichi TANIGUCHI, Yasuaki OKITA, Chikaumi SAWANISHI, Hiroshi MATSUDA, Motomichi YAMAMOTO
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Publication number: 20240123700Abstract: A damage evaluation device for a press-forming die includes: evaluation dies installed in a pressing device configured to press-form a metal material; and an observation device configured to observe damage behavior of a die steel material and surface coating constituting the evaluation dies. The evaluation dies include: a perforating unit configured to form a hole in the metal material; a first shearing unit configured to shear the metal material in which the hole is formed into a predetermined metal component shape; and a second shearing unit configured to separate a metal component from the metal material, and dies of the perforating unit, the first shearing unit and the second shearing unit are formed of the die steel material and have a structure that enables replacement with another die made of predetermined material and applied with predetermined surface coating treatment.Type: ApplicationFiled: March 4, 2022Publication date: April 18, 2024Applicant: JFE STEEL CORPORATIONInventor: Hiroto MIYAKE
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Publication number: 20240123542Abstract: A laser cutting method for a steel strip, includes cutting a vicinity of a joint obtained by joining a rear end of a preceding steel strip and a front end of a following steel strip by using a pulse-type laser beam, wherein output of the pulse-type laser beam is set to 0.5 kw or more per 1 ms, a processing point diameter of the pulse-type laser beam is set to 0.1 mm or more and less than 0.6 mm, and a ratio between a pulse period time and a down-time is set to 0.3 or more and less than 0.8.Type: ApplicationFiled: October 26, 2021Publication date: April 18, 2024Applicant: JFE Steel CorporationInventors: Noriki Fujita, Yukihiro Matsubara, Takayuki Fukunaga
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Publication number: 20240124949Abstract: A high-strength stainless steel seamless pipe for oil country tubular goods has a composition that contains, in mass %, C: 0.012 to 0.05%, Si: 0.05 to 0.50%, Mn: 0.04 to 1.80%, P: 0.030% or less, S: 0.005% or less, Cr: 11.0 to 14.0%, Ni: 0.5 to 6.5%, Mo: 0.5 to 3.0%, Al: 0.005 to 0.10%, V: 0.005 to 0.20%, Co: 0.01 to 0.3%, N: 0.002 to 0.15%, O: 0.010% or less, and Ti: 0.001 to 0.20%, and in which Cr, Ni, Mo, Cu, C, Si, Mn, N, and Ti satisfy predetermined relations, and the balance is Fe and incidental impurities, the high-strength stainless steel seamless pipe having a steel microstructure with 6 to 20% retained austenite in terms of a volume percentage, a yield strength of 758 MPa or more, and an absorption energy vE?60 at ?60° C. of 70 J or more.Type: ApplicationFiled: January 26, 2022Publication date: April 18, 2024Applicant: JFE Steel CorporationInventors: Kenichiro Eguchi, Masao Yuga
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Publication number: 20240124964Abstract: Provided is a galvanized steel sheet having a TS of 980 MPa or more, high YS, excellent ductility, strain hardenability, and hole expansion formability. A base steel sheet has a defined chemical composition and a steel microstructure as follows: area ratio of ferrite: 65.0% or less (including 0%), area ratio of bainitic ferrite: 5.0% or more and 40.0% or less, area ratio of tempered martensite: 0.5% or more and 80.0% or less, area ratio of retained austenite: 3.0% or more, area ratio of fresh martensite: 20.0% or less (including 0%), SBF+STM+2×SMA: 65.0% or more, SMA1/SMA: 0.80 or less, and SMA2/SMA: 0.20 or more.Type: ApplicationFiled: March 18, 2022Publication date: April 18, 2024Applicant: JFE STEEL CORPORATIONInventors: Sho HIGUCHI, Yoshiyasu KAWASAKI, Tatsuya NAKAGAITO, Tomomi KANAZAWA, Shunsuke YAMAMOTO
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Patent number: 11959149Abstract: Provided are a grain-oriented electrical steel sheet having excellent iron loss property without using magnetic domain refining treatment and an iron core produced using the same. The steel sheet comprises: a predetermined chemical composition; and a steel microstructure in which: crystal grains are made up of coarse secondary recrystallized grains of 5.0 mm or more, fine grains of more than 2.0 mm and less than 5.0 mm contained at a frequency of 0.2 to 5 grains per cm2, and very fine grains of 2.0 mm or less; for each coarse secondary recrystallized grain extending through the sheet in a thickness direction, an area ratio of a region in which projected surfaces of exposed areas of the coarse secondary recrystallized grain on a front side and a back side of the sheet coincide with each other to each of the exposed areas is 95% or more.Type: GrantFiled: January 30, 2020Date of Patent: April 16, 2024Assignee: JFE STEEL CORPORATIONInventors: Takeshi Imamura, Makoto Watanabe
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Patent number: 11961647Abstract: Vibration of an iron core is reduced to reduce transformer noise. An iron core for a transformer comprises a plurality of grain-oriented electrical steel sheets stacked together, wherein at least one of the plurality of grain-oriented electrical steel sheets: (1) has a region in which closure domains are formed in a direction crossing a rolling direction and a region in which no closure domains are formed; (2) has an area ratio R0 of 0.10% to 3.0%, the area ratio R0 being defined as a ratio of S0 to S; and (3) has an area ratio R1a of 50% or more, the area ratio R1a being defined as a ratio of S1a to S1.Type: GrantFiled: March 29, 2019Date of Patent: April 16, 2024Assignee: JFE STEEL CORPORATIONInventors: Takeshi Omura, Hirotaka Inoue, Seiji Okabe
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Patent number: 11962184Abstract: In the production of a non-oriented electrical steel sheet by subjecting a steel slab having a certain component composition to a hot rolling, a hot-band annealing, a cold rolling and a finish annealing, the conditions of the finish annealing are controlled such that a yield stress of the steel sheet after the finish annealing is not less than 480 MPa. Also, when a motor core is produced by using the above steel sheet, there can be provided a non-oriented electrical steel sheet capable of producing a rotor core and a stator core as the same raw material where the stator core is subjected to a stress relief annealing at a soaking temperature of 780 to 950° C. in an atmosphere having a nitrogen content of not more than 30 vol % and a dew point of not higher than ?20° C., while a motor core is produced with such a steel sheet.Type: GrantFiled: June 15, 2020Date of Patent: April 16, 2024Assignee: JFE Steel CorporationInventors: Yoshiaki Zaizen, Yoshihiko Oda, Tomoyuki Okubo, Takaaki Tanaka, Yukino Miyamoto
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Patent number: 11959157Abstract: Provided is a high-Mn steel having excellent low-temperature toughness and excellent surface characteristics. A high-Mn steel comprises: a chemical composition containing, in mass %, C: 0.100 to 0.700%, Si: 0.05 to 1.00%, Mn: 20.0 to 35.0%, P: ?0.030%, S: ?0.0070%, Al: 0.010 to 0.070%, Cr: 0.50 to 5.00%, N: 0.0050 to 0.0500%, O: ?0.0050%, Ti: ?0.005%, and Nb: ?0.005%, with a balance consisting of Fe and inevitable impurities; and a microstructure having austenite as a matrix, wherein in the microstructure, a Mn concentration of a Mn-concentrated portion is 38.0% or less, and an average KAM value is 0.3 or more, yield stress is 400 MPa or more, absorbed energy vE?196 in a Charpy impact test at ?196° C. is 100 J or more, and percent brittle fracture is less than 10%.Type: GrantFiled: July 31, 2019Date of Patent: April 16, 2024Assignee: JFE STEEL CORPORATIONInventors: Daichi Izumi, Shigeki Kitsuya, Keiji Ueda, Koichi Nakashima
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Patent number: 11959147Abstract: A top-blowing lance nozzle is configured to freely switch an adequate expansion condition so as to control an oxygen-blowing amount and a jetting velocity independently of each other without requiring a plurality of lance nozzles or a mechanically movable part. A lance nozzle is configured to blow refining oxygen to molten iron charged in a reaction vessel while a gas is blown from a top-blowing lance to the molten iron. One or more blowing holes for blowing a working gas are on an inner wall side surface of the nozzle, at a site where the lance nozzle has a minimum cross-sectional area in a nozzle axis direction or at a neighboring site of the site.Type: GrantFiled: April 2, 2020Date of Patent: April 16, 2024Assignee: JFE STEEL CORPORATIONInventors: Yumi Murakami, Nobuhiko Oda, Yusuke Fujii, Goro Okuyama, Shota Amano, Shinji Koseki, Shingo Sato, Yukio Takahashi, Ryo Kawabata, Naoki Kikuchi, Atsuo Yuasa