Patents by Inventor Yoichi Makimizu
Yoichi Makimizu has filed for patents to protect the following inventions. This listing includes patent applications that are pending as well as patents that have already been granted by the United States Patent and Trademark Office (USPTO).
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Publication number: 20240117517Abstract: Disclosed is an Fe-based electroplated steel sheet including: a Si-containing cold-rolled steel sheet containing Si in an amount of 0.1 mass % or more and 3.0 mass % or less; and an Fe-based electroplating layer formed on at least one surface of the Si-containing cold-rolled steel sheet with a coating weight per surface of 5.0 g/m2 or more, in which in an intensity profile measured by glow discharge optical emission spectrometry, a peak of emission intensity at wavelengths indicating Si is detected within a range from a surface of the Fe-based electroplating layer to more than 0.2 ?m in a thickness direction and not more than a thickness of the Fe-based electroplating layer, and an average value of C concentration in a region ranging from 10 ?m to 20 ?m in the thickness direction from the surface of the Fe-based electroplating layer is 0.10 mass % or less.Type: ApplicationFiled: November 5, 2021Publication date: April 11, 2024Applicant: JFE STEEL CORPORATIONInventors: Shunsuke YAMAMOTO, Katsutoshi TAKASHIMA, Yusuke OKUMURA, Tomomi KANAZAWA, Katsuya HOSHINO, Takashi KAWANO, Takako YAMASHITA, Hiroshi MATSUDA, Yoichi MAKIMIZU
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Publication number: 20240035105Abstract: Provided is a hot-dip galvanized steel sheet having both high strength and good workability, as well as excellent coating quality. The chemical composition of the base steel sheet is set within a specified range, the steel microstructure of the base steel sheet is a complex structure of ferrite, martensite and bainite, oxygen is present as oxides in the surface layer of the base steel sheet in an amount of 0.05 g/m2 or more and 0.50 g/m2 or less per surface, and the hot-dip galvanized layer contains Fe in an amount of 0.40 mass % or more.Type: ApplicationFiled: December 15, 2021Publication date: February 1, 2024Applicant: JFE STEEL CORPORATIONInventors: Takuya HIRASHIMA, Tatsuya NAKAGAITO, Masaki KOBA, Yoichi MAKIMIZU, Katsuya HATA, Shotaro TERASHIMA
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Publication number: 20240009962Abstract: To provide an Fe-based electroplated steel sheet that not only has excellent chemical convertibility or excellent coating appearance when subjected to hot-dip galvanizing, but also has excellent resistance to cracking in resistance welding. Disclosed is an Fe-based plated steel sheet including: a cold-rolled steel sheet having a chemical composition containing Si in an amount of 0.1 mass % or more and 3.0 mass % or less; and an Fe-based electroplating layer formed on one or both surfaces of the cold-rolled steel sheet with a coating weight per surface of 1.0 g/m2 or more, in which a thickness of an internal oxidation layer is 2.00 ?m or less, and an average value of C concentration in a range of 10 ?m to 20 ?m in a thickness direction from the surface of the Fe-based electroplating layer is 0.10 mass % or less.Type: ApplicationFiled: November 5, 2021Publication date: January 11, 2024Applicant: JFE STEEL CORPORATIONInventors: Shunsuke YAMAMOTO, Yusuke OKUMURA, Katsutoshi TAKASHIMA, Mai AOYAMA, Tomomi KANAZAWA, Katsuya HOSHINO, Yoichi MAKIMIZU, Takashi KAWANO, Takako YAMASHITA, Hiroshi MATSUDA
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Publication number: 20230407485Abstract: Provided is an alloyed galvanized steel sheet with excellent resistance to cracking in resistance welding at a welded portion, even if crystal orientations of an Fe-based electroplating layer and a cold-rolled steel sheet are integrated at a high ratio at the interface between the Fe-based electroplating layer and the cold-rolled steel sheet. The alloyed galvanized steel sheet has a Si-containing cold-rolled steel sheet containing Si in an amount of 0.1 mass % to 3.0 mass %; an Fe-based electroplating layer formed on at least one surface of the Si-containing cold-rolled steel sheet with a coating weight per surface exceeding 20.0 g/m2, and an alloyed galvanized layer formed on the Fe-based electroplating layer, where crystal orientations of the Fe-based electroplating layer and the Si-containing cold-rolled steel sheet are integrated at a ratio of more than 50% at the interface between the Fe-based electroplating layer and the Si-containing cold-rolled steel sheet.Type: ApplicationFiled: November 5, 2021Publication date: December 21, 2023Applicant: JFE STEEL CORPORATIONInventors: Shunsuke YAMAMOTO, Katsutoshi TAKASHIMA, Mai AOYAMA, Yusuke OKUMURA, Tomomi KANAZAWA, Katsuya HOSHINO, Hiroshi MATSUDA, Ei OKUMURA, Yoichi MAKIMIZU, Masaki KOBA
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Publication number: 20230407447Abstract: Provided is a galvanized steel sheet with excellent resistance to cracking in resistance welding at a welded portion, even if crystal orientations of an Fe-based electroplating layer and a cold-rolled steel sheet are integrated at a high ratio at the interface between the Fe-based electroplating layer and the cold-rolled steel sheet. The galvanized steel sheet has a Si-containing cold-rolled steel sheet containing Si in an amount of 0.1 mass % to 3.0 mass %; an Fe-based electroplating layer formed on at least one surface of the Si-containing cold-rolled steel sheet with a coating weight per surface of more than 20.0 g/m2, and a galvanized layer formed on the Fe-based electroplating layer, where crystal orientations of the Fe-based electroplating layer and the Si-containing cold-rolled steel sheet are integrated at a ratio of more than 50 % at the interface between the Fe-based electroplating layer and the Si-containing cold-rolled steel sheet.Type: ApplicationFiled: November 5, 2021Publication date: December 21, 2023Applicant: JFE STEEL CORPORATIONInventors: Shunsuke YAMAMOTO, Katsutoshi TAKASHIMA, Mai AOYAMA, Yusuke OKUMURA, Tomomi KANAZAWA, Katsuya HOSHINO, Hiroshi MATSUDA, Ei OKUMURA, Yoichi MAKIMIZU, Masaki KOBA
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Publication number: 20230407484Abstract: Disclosed is a galvannealed steel sheet including: a Si-containing cold-rolled steel sheet containing Si in an amount of 0.1 mass % or more and 3.0 mass % or less; an Fe-based electroplating layer formed on at least one surface of the Si-containing cold-rolled steel sheet; and a galvannealed layer formed on the Fe-based electroplating layer, in which in an intensity profile measured by glow discharge optical emission spectrometry, ISi,Fe/ISi,bulk is 0.30 or more, and an average value of C concentration in a region ranging from 10 ?m to 20 ?m in the thickness direction from the interface between the galvannealed layer and the Fe-based electroplating layer towards the Fe-based electroplating layer is 0.10 mass % or less.Type: ApplicationFiled: November 5, 2021Publication date: December 21, 2023Applicant: JFE STEEL CORPORATIONInventors: Shunsuke YAMAMOTO, Katsutoshi TAKASHIMA, Yusuke OKUMURA, Tomomi KANAZAWA, Katsuya HOSHINO, Takashi KAWANO, Takako YAMASHITA, Hiroshi MATSUDA, Yoichi MAKIMIZU
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Publication number: 20230407506Abstract: Provided is a steel sheet with excellent resistance to cracking in resistance welding at a welded portion, even if the crystal orientations of an Fe-based electroplating layer and a Si-containing cold-rolled steel sheet are integrated at a high ratio at the interface between the Fe-based electroplating layer and the Si-containing cold-rolled steel sheet. Provided is an Fe-based electroplated steel sheet having a Si-containing cold-rolled steel sheet containing Si in an amount of 0.1 mass % or more and 3.0 mass % or less; and an Fe-based electroplating layer formed on at least one surface of the Si-containing cold-rolled steel sheet with a coating weight per surface of more than 20.0 g/m2, where the crystal orientations of the Fe-based electroplating layer and the Si-containing cold-rolled steel sheet are integrated at a ratio of more than 50% at the interface between the Fe-based electroplating layer and the Si-containing cold-rolled steel sheet.Type: ApplicationFiled: November 5, 2021Publication date: December 21, 2023Applicant: JFE STEEL CORPORATIONInventors: Shunsuke YAMAMOTO, Katsutoshi TAKASHIMA, Mai AOYAMA, Yusuke OKUMURA, Tomomi KANAZAWA, Katsuya HOSHINO, Hiroshi MATSUDA, Ei OKUMURA, Yoichi MAKIMIZU, Masaki KOBA
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Publication number: 20230374639Abstract: To provide a steel sheet with excellent resistance to cracking in resistance welding at a welded portion. Disclosed is a galvanized steel sheet including: a Si-containing cold-rolled steel sheet containing Si in an amount of 0.1 mass % or more and 3.0 mass % or less; an Fe-based electroplating layer formed on at least one surface of the Si-containing cold-rolled steel sheet with a coating weight per surface of 5.0 g/m2 or more; and a galvanized layer formed on the Fe-based electroplating layer, in which in an intensity profile measured by glow discharge optical emission spectrometry, ISi,Fe/ISi,bulk is 0.50 or more, and an average value of C concentration in a region ranging from 10 ?m to 20 ?m from an interface between the galvanized layer and the Fe-based electroplating layer towards the Fe-based electroplating layer is 0.10 mass % or less.Type: ApplicationFiled: November 5, 2021Publication date: November 23, 2023Applicant: JFE STEEL CORPORATIONInventors: Shunsuke YAMAMOTO, Katsutoshi TAKASHIMA, Yusuke OKUMURA, Tomomi KANAZAWA, Katsuya HOSHINO, Takashi KAWANO, Takako YAMASHITA, Hiroshi MATSUDA, Yoichi MAKIMIZU
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Patent number: 11649520Abstract: A continuous hot-dip galvanizing apparatus has a vertical annealing furnace, one or more hearth rolls, a hot-dip galvanizing apparatus, an alloying line, and humidified gas supply ports. When the steel sheet having a Si content of 0.2 mass % or more is conveyed inside the annealing furnace, the humidified gas supply ports positioned in a latter part of the soaking zone supply the humidified gas to the soaking zone and the at least one dry gas supply port supplies the dry gas to the soaking zone. When the steel sheet having a Si content of less than 0.2 mass % is conveyed inside the annealing furnace, the plurality of the humidified gas supply ports do not supply the humidified gas to the soaking zone and the at least one dry gas supply port supplies the dry gas to the soaking zone.Type: GrantFiled: August 23, 2022Date of Patent: May 16, 2023Assignee: JFE STEEL CORPORATIONInventors: Gentaro Takeda, Yoichi Makimizu, Yoshikazu Suzuki, Yoshimasa Himei, Hideyuki Takahashi
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Patent number: 11535922Abstract: Provided is a method for manufacturing a high-strength galvanized steel sheet. Heating in a first half of oxidizing treatment is performed at a temperature of 400° C. to 750° C. in an atmosphere having a particular O2 concentration and a particular H2O concentration, and heating in a second half of the oxidizing treatment is performed at a temperature of 600° C. to 850° C. in an atmosphere having a particular O2 concentration and a particular H2O concentration. Subsequently, heating in a heating zone for reduction annealing is performed to a temperature of 650° C. to 900° C. at a particular heating rate in an atmosphere having a particular H2 concentration and a particular H2O concentration with the balance being N2 and inevitable impurities, and soaking in a soaking zone for the reduction annealing is performed in an atmosphere having a particular H2 concentration and a particular H2O concentration with the balance being N2 and inevitable impurities.Type: GrantFiled: September 14, 2017Date of Patent: December 27, 2022Assignee: JFE Steel CorporationInventors: Yoichi Makimizu, Gentaro Takeda, Hiroshi Hasegawa, Yoshimasa Himei, Yoshikazu Suzuki
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Publication number: 20220403480Abstract: A continuous hot-dip galvanizing apparatus has a vertical annealing furnace, one or more hearth rolls, a hot-dip galvanizing apparatus, an alloying line, and humidified gas supply ports. When the steel sheet having a Si content of 0.2 mass % or more is conveyed inside the annealing furnace, the humidified gas supply ports positioned in a latter part of the soaking zone supply the humidified gas to the soaking zone and the at least one dry gas supply port supplies the dry gas to the soaking zone. When the steel sheet having a Si content of less than 0.2 mass % is conveyed inside the annealing furnace, the plurality of the humidified gas supply ports do not supply the humidified gas to the soaking zone and the at least one dry gas supply port supplies the dry gas to the soaking zone.Type: ApplicationFiled: August 23, 2022Publication date: December 22, 2022Applicant: JFE STEEL CORPORATIONInventors: Gentaro TAKEDA, Yoichi MAKIMIZU, Yoshikazu SUZUKI, Yoshimasa HIMEI, Hideyuki TAKAHASHI
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Patent number: 11459631Abstract: Provided is a method for producing a galvannealed steel sheet. When the steel sheet passing through the soaking zone is a type of steel containing 0.2 mass % or more of Si, both dry gas and humidified gas are supplied to the soaking zone, where the humidified gas is supplied only from the humidified gas supply port positioned in a latter part of the soaking zone among a plurality of humidified gas supply ports, where the latter part of the soaking zone is determined considering a sheet passing speed V and a target temperature T on the exit side of the soaking zone.Type: GrantFiled: February 19, 2018Date of Patent: October 4, 2022Assignee: JFE STEEL CORPORATIONInventors: Gentaro Takeda, Yoichi Makimizu, Yoshikazu Suzuki, Yoshimasa Himei, Hideyuki Takahashi
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Patent number: 11447852Abstract: A high-strength galvanized steel sheet having improved post-work impact resistance, a method for producing the high-strength galvanized steel sheet, and a high-strength member produced using the steel sheet. The high-strength galvanized steel sheet includes a steel sheet having a microstructure including ferrite and carbide-free bainite, martensite and carbide-containing bainite, and retained austenite, the total area fraction of ferrite and carbide-free bainite being 0% to 55%, the total area fraction of martensite and carbide-containing bainite being 45% to 100%, and the area fraction of retained austenite being 0% to 5%. Additionally, a galvanizing layer is disposed on the steel sheet. The density of gaps that cut across the entire thickness of the galvanizing layer in a cross section of the galvanizing layer, which is taken in the thickness direction so as to be perpendicular to the rolling direction, is 10 gaps/mm or more.Type: GrantFiled: January 26, 2017Date of Patent: September 20, 2022Assignee: JFE STEEL CORPORATIONInventors: Hiroshi Hasegawa, Yoshimasa Funakawa, Hiromi Yoshitomi, Yoichi Makimizu, Yoshitsugu Suzuki, Gentaro Takeda, Yoshikazu Suzuki, Yoshimasa Himei
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Patent number: 11421312Abstract: A method comprises: annealing a steel sheet by conveying the steel sheet through a heating zone, a soaking zone, and a cooling zone in the stated order in an annealing furnace; and then applying a hot-dip galvanized coating onto the steel sheet discharged from the cooling zone. Reducing or non-oxidizing humidified gas and reducing or non-oxidizing dry gas are supplied into the soaking zone. A CO gas concentration is measured using a CO gas concentration meter provided in an exhaust portion for gas in the soaking zone. A decarburized layer thickness of the steel sheet is calculated from the measured CO gas concentration. At least one of a flow rate and a dew point of the humidified gas is controlled so that the calculated decarburized layer thickness is less than or equal to a predetermined thickness.Type: GrantFiled: April 16, 2018Date of Patent: August 23, 2022Assignee: JFE STEEL CORPORATIONInventors: Gentaro Takeda, Yoichi Makimizu, Gosuke Ikeda, Hideyuki Takahashi
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Patent number: 11384407Abstract: Provided are a high-strength galvannealed steel sheet, and a manufacturing method therefor. The manufacturing method is for a high-strength galvannealed steel sheet which includes a zinc coated layer with a coating weight of 20 to 120 g/m2 per side on a surface of a steel sheet having a chemical composition containing, in mass %, C: 0.03 to 0.35%, Si: 0.01 to 1.00%, Mn: 3.6 to 8.0%, Al: 0.001 to 1.00%, P: 0.100% or less, and S: 0.010% or less, with the balance being Fe and inevitable impurities. The method includes: setting a cold rolling reduction ratio to 20% or more and 35% or less when cold rolling is performed on the steel sheet, and setting a maximum steel sheet temperature to be reached in an annealing furnace to 600° C. or higher and 700° C. or lower when annealing is further performed on the steel sheet.Type: GrantFiled: June 5, 2017Date of Patent: July 12, 2022Assignee: JFE STEEL CORPORATIONInventors: Satoshi Maeda, Yoichi Makimizu, Yoshitsugu Suzuki, Yoshiyasu Kawasaki
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Patent number: 11248277Abstract: A method for manufacturing a high-strength galvanized steel sheet having excellent strength-elongation balance, coating adhesiveness, and surface appearance. The method includes: (i) a first heating process of heating a steel sheet having a predetermined chemical composition, (ii) a first pickling process of pickling the steel sheet which was subjected to the first heating process in an oxidizing acidic aqueous solution, (iii) a second pickling process of pickling the steel sheet which was subjected to the first pickling process in a non-oxidizing acidic aqueous solution, (iv) a second heating process of holding the steel sheet, which was subjected to the second pickling process, at a temperature range of 700° C. or higher and 900° C. or lower in a hydrogen-containing atmosphere for 20 seconds or more and 300 seconds or less, and (v) performing a galvanizing treatment on the steel sheet which was subjected to the second heating process.Type: GrantFiled: April 24, 2018Date of Patent: February 15, 2022Assignee: JFE STEEL CORPORATIONInventors: Shotaro Terashima, Yusuke Fushiwaki, Yoichi Makimizu, Hiroyuki Masuoka, Hiroshi Hasegawa
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Patent number: 11136641Abstract: High-strength galvannealed steel sheet including any of a) an oxide containing Fe and Mn, b) an oxide containing Fe and Mn and an Fe oxide, c) an oxide containing Fe and Mn and a Mn oxide, d) an oxide containing Fe and Mn, an Fe oxide, and a Mn oxide, and e) an Fe oxide and a Mn oxide is present in a zinc coated layer. The total amount of oxide is 0.01 to 0.100 g/m2; the ratio by mass % of Mn to Fe, e.g., Mn/Fe, contained in the oxide is 0.10 to 10.00; an oxide of at least one selected from Fe and Mn is present in an amount of 60% or more; and an oxide of at least one selected from Fe and Mn is present in a surface layer portion of a steel sheet in an amount of 0.040 g/m2 or less (not including zero).Type: GrantFiled: December 8, 2016Date of Patent: October 5, 2021Assignee: JFE STEEL CORPORATIONInventors: Satoshi Maeda, Yoichi Makimizu, Yoshitsugu Suzuki, Katsumi Yamada, Yoshiyasu Kawasaki
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Patent number: 10988836Abstract: A method for producing a high-strength galvanized steel sheet having excellent fatigue resistance properties. The method includes an oxidation processing in which a steel sheet is heated at a temperature of 400 to 750° C. in an atmosphere having an O2 concentration of 1000 ppm by volume or more and a H2O concentration of 1000 ppm by volume or more, and the steel sheet is heated at a temperature of 600 to 850° C. in an atmosphere having an O2 concentration of less than 1000 ppm by volume and a H2O concentration of 1000 ppm by volume or more. The method also includes reduction-annealing in which the steel sheet is heated at a heating rate of 0.1° C./sec or more to a temperature of 650 to 900° C. in an atmosphere having a H2 concentration of 5 to 30 vol % and a H2O concentration of 10 to 1000 ppm by volume.Type: GrantFiled: February 16, 2017Date of Patent: April 27, 2021Assignee: JFE STEEL CORPORATIONInventors: Yoichi Makimizu, Yoshitsugu Suzuki, Gentaro Takeda, Hiroshi Hasegawa
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Patent number: 10941475Abstract: A method for producing a high-strength galvanized steel sheet having excellent fatigue resistance properties. The method includes an oxidation processing in which a steel sheet is heated at a temperature of 400 to 750° C. in an atmosphere having an O2 concentration of 1000 ppm by volume or more and a H2O concentration of 1000 ppm by volume or more, and the steel sheet is heated at a temperature of 600 to 850° C. in an atmosphere having an O2 concentration of less than 1000 ppm by volume and a H2O concentration of 1000 ppm by volume or more. The method also includes reduction-annealing in which the steel sheet is heated at a heating rate of 0.1° C./sec or more to a temperature of 650 to 900° C. in an atmosphere having a H2 concentration of 5 to 30 vol % and a H2O concentration of 10 to 1000 ppm by volume.Type: GrantFiled: February 16, 2017Date of Patent: March 9, 2021Assignee: JFE STEEL CORPORATIONInventors: Yoichi Makimizu, Yoshitsugu Suzuki, Gentaro Takeda, Hiroshi Hasegawa
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Publication number: 20200308664Abstract: Provided are a high-strength galvannealed steel sheet, and a manufacturing method therefor. The manufacturing method is for a high-strength galvannealed steel sheet which includes a zinc coated layer with a coating weight of 20 to 120 g/m2 per side on a surface of a steel sheet having a chemical composition containing, in mass %, C: 0.03 to 0.35%, Si: 0.01 to 1.00%, Mn: 3.6 to 8.0%, Al: 0.001 to 1.00%, P: 0.100% or less, and S: 0.010% or less, with the balance being Fe and inevitable impurities. The method includes: setting a cold rolling reduction ratio to 20% or more and 35% or less when cold rolling is performed on the steel sheet, and setting a maximum steel sheet temperature to be reached in an annealing furnace to 600° C. or higher and 700° C. or lower when annealing is further performed on the steel sheet.Type: ApplicationFiled: June 5, 2017Publication date: October 1, 2020Applicant: JFE Steel CorporationInventors: Satoshi Maeda, Yoichi Makimizu, Yoshitsugu Suzuki, Yoshiyasu Kawasaki