Patents by Inventor Mai Miyata
Mai Miyata 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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Patent number: 9758847Abstract: Provided is a hot-rolled steel sheet having a composition containing 0.04 mass percent to 0.20 mass percent C, 0.7 mass percent to 2.3 mass percent Si, 0.8 mass percent to 2.8 mass percent Mn, 0.1 mass percent or less P, 0.01 mass percent or less S, 0.1 mass percent or less Al, and 0.008 mass percent or less N, the remainder being Fe and inevitable impurities. Internal oxides containing one or more selected from the group consisting of Si, Mn, and Fe are present at grain boundaries and in grains in a base metal. The internal oxides present at the grain boundaries in the base metal are located within 5 ?m from the surface of the base metal. The difference between the depths at which the internal oxides are formed in the cross direction of the steel sheet is 2 ?m or less.Type: GrantFiled: November 2, 2012Date of Patent: September 12, 2017Assignee: JFE Steel CorporationInventors: Mai Miyata, Yoshitsugu Suzuki, Yasunobu Nagataki, Yoshiyasu Kawasaki, Hirokazu Sugihara
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Patent number: 9677148Abstract: A method for manufacturing a galvanized steel sheet includes heating a base steel sheet in a heating zone such that the surface of the base steel sheet is heated at a temperature of 600° C. or higher and 790° C. or lower while a furnace temperature T° C. in the heating zone of an annealing furnace is controlled based on the water vapor partial pressure PH2Oin Air of air fed into the heating zone, the base steel sheet having a chemical composition consisting of, by mass %, C: 0.05% or more and 0.25% or less, Si: 0.1% or more and 3.0% or less, Mn: 0.5% or more and 3.0% or less, P: 0.001% or more and 0.10% or less, Al: 0.01% or more and 3.00% or less, S: 0.200% or less, and the balance being Fe and inevitable impurities, heating the base steel sheet in the heating zone such that the surface of the base steel sheet is heated at a temperature of 630° C. or higher and 850° C.Type: GrantFiled: November 29, 2013Date of Patent: June 13, 2017Assignee: JFE Steel CorporationInventors: Minoru Tanaka, Yoshitsugu Suzuki, Mai Miyata, Yasunobu Nagataki
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Patent number: 9476111Abstract: A hot dip galvanized steel sheet includes a steel sheet, a hot dip galvanizing layer, and an intermetallic compound, in which the steel sheet has a chemical composition containing, by mass %, C: 0.03% or more and 0.70% or less, Si: 0.10% or less, Mn: 0.5% or more and 0.9% or less, P: 0.020% or more and 0.050% or less, S: 0.010% or less, Nb: 0.010% or more and 0.035% or less, N: 0.005% or less, Al: 0.10% or less, and the balance being Fe and inevitable impurities, in which the hot dip galvanizing layer contains 0.3% or more and 0.6% or less of Al, and in which the intermetallic compound contains 0.12 gm?2 or more and 0.22 gm?2 or less of Al and Fe2Al5 having an average grain diameter of 1 ?m or less.Type: GrantFiled: December 24, 2013Date of Patent: October 25, 2016Assignee: JFE Steel CorporationInventors: Yoshitsugu Suzuki, Mai Miyata, Yasunobu Nagataki
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Publication number: 20160194744Abstract: A high-strength hot-dip galvanized steel sheet is produced by a method that includes a first heating step of holding a steel sheet at a temperature for a time in an atmosphere having a H2 concentration and a dew point, a cooling step of cooling the steel sheet after the first heating step, an electrolytic treatment step of subjecting the steel sheet after the cooling step to electrolytic treatment under specific conditions, a second heating step of holding the steel sheet after the electrolytic treatment step at a temperature for a time in an atmosphere having a H2 concentration and a dew point, and a coating treatment step of subjecting the steel sheet after the second heating step to hot-dip galvanizing treatment.Type: ApplicationFiled: August 12, 2014Publication date: July 7, 2016Applicant: UFE Steel CorporationInventors: Mai Miyata, Yoshitsugu Suzuki, Yasunobu Nagataki
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Patent number: 9340859Abstract: A method of manufacturing a high strength galvanized steel sheet has a first heating step including heating to 400° C. to 750° C. in an atmosphere containing O2: 0.1 to 20 percent and H2O: 1 to 50 percent and heating to 600° C. to 850° C. in an atmosphere containing O2: 0.01 to less than 0.1 percent and H2O: 1 to 20 percent is applied to a steel sheet, a second heating step includes holding the steel sheet in an atmosphere containing H2: 1 to 50 percent and having a dew point of 0° C. or lower at 750° C. to 900° C. for 15 to 600 s, cooling to a temperature of 450° C. to 550° C., and holding is performed at that temperature for 10 to 200 s, and a galvanization treatment is applied.Type: GrantFiled: June 1, 2012Date of Patent: May 17, 2016Assignee: JFE Steel CorporationInventors: Mai Miyata, Yoshitsugu Suzuki, Yoshiyasu Kawasaki, Tatsuya Nakagaito, Shinjiro Kaneko, Yasunobu Nagataki
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Publication number: 20150337427Abstract: A hot dip galvanized steel sheet includes a steel sheet, a hot dip galvanizing layer, and an intermetallic compound, in which the steel sheet has a chemical composition containing, by mass %, C: 0.03% or more and 0.70% or less, Si: 0.10% or less, Mn: 0.5% or more and 0.9% or less, P: 0.020% or more and 0.050% or less, S: 0.010% or less, Nb: 0.010% or more and 0.035% or less, N: 0.005% or less, Al: 0.10% or less, and the balance being Fe and inevitable impurities, in which the hot dip galvanizing layer contains 0.3% or more and 0.6% or less of Al, and in which the intermetallic compound contains 0.12 gm?2 or more and 0.22 gm?2 or less of Al and Fe2Al5 having an average grain diameter of 1 ?m or less.Type: ApplicationFiled: December 24, 2013Publication date: November 26, 2015Applicant: JFE STEEL CORPORATIONInventors: Yoshitsugu Suzuki, Mai Miyata, Yasunobu Nagataki
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Publication number: 20150315692Abstract: A method for manufacturing a galvanized steel sheet includes heating a base steel sheet in a heating zone such that the surface of the base steel sheet is heated at a temperature of 600° C. or higher and 790° C. or lower while a furnace temperature T° C. in the heating zone of an annealing furnace is controlled based on the water vapor partial pressure PH2Oin Air of air fed into the heating zone, the base steel sheet having a chemical composition consisting of, by mass %, C: 0.05% or more and 0.25% or less, Si: 0.1% or more and 3.0% or less, Mn: 0.5% or more and 3.0% or less, P: 0.001% or more and 0.10% or less, Al: 0.01% or more and 3.00% or less, S: 0.200% or less, and the balance being Fe and inevitable impurities, heating the base steel sheet in the heating zone such that the surface of the base steel sheet is heated at a temperature of 630° C. or higher and 850° C.Type: ApplicationFiled: November 29, 2013Publication date: November 5, 2015Applicant: JFE STEEL CORPORATIONInventors: Minoru Tanaka, Yoshitsugu Suzuki, Mai Miyata, Yasunobu Nagataki
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Patent number: 9090952Abstract: A high-strength cold-rolled steel sheet having high chemical convertibility and a tensile strength of 590 MPa or more and a method for producing such a steel sheet are provided. The steel sheet contains, in terms of percent by mass, C: 0.05 to 0.3%, Si: 0.6 to 3.0%, Mn: 1.0 to 3.0%, P: 0.1% or less, S: 0.05% or less, Al: 0.01 to 1%, N: 0.01% or less, and the balance being Fe and unavoidable impurities. The coverage ratio of reduced iron on a steel sheet surface is 40% or more. In order to produce such a steel sheet, an oxidation treatment is performed after cold rolling. Subsequently, annealing is conducted in a furnace in a 1 to 10 vol % H2+balance N2 gas atmosphere with a dew point of ?25° C. or less.Type: GrantFiled: December 24, 2010Date of Patent: July 28, 2015Assignee: JFE Steel CorporationInventors: Yoichi Makimizu, Yoshitsugu Suzuki, Mai Miyata, Naoto Yoshimi, Junichiro Hirasawa, Shinji Otsuka, Hideki Nagano, Kohei Hasegawa
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Patent number: 8906516Abstract: A galvannealed steel sheet having high corrosion resistance after painting includes, on a mass percent basis, C: 0.05% to 0.15%, Si: 0.1% to 1.0%, Mn: 0.5% to 2.7%, Al: ?1.00%, P: ?0.025%, S: ?0.025%, and Cr: 0% to 0.8% as chemical components, the remainder being Fe and incidental impurities. The galvannealed steel sheet includes a galvannealed layer in an amount of 20 to 120 g/m2 per side, a percentage of exposed zinc metal of the galvannealed layer surface being 20% or more and less than 80%, and an amount of internal oxidation in a region disposed not more than 5 ?m from the surface of the steel sheet is 0.02 g/m2 or more and 0.1 g/m2 or less: Si?0.68%, Cr??1.25Si+0.85, and Si>0.68%, Cr=0, wherein Si and Cr denote respective contents (mass %) of Si and Cr.Type: GrantFiled: September 20, 2012Date of Patent: December 9, 2014Assignee: JFE Steel CorporationInventors: Yoshitsugu Suzuki, Mai Miyata, Yoichi Makimizu
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Publication number: 20140342182Abstract: A galvannealed steel sheet having high corrosion resistance after painting, includes, on a mass percent basis, C: 0.05% to 0.30%, Si: 1.0% to 3.0%, Mn: 0.5% to 3.0%, Al: 0.01% to 3.00%, S: 0.001% to 0.010%, and P: 0.001% to 0.100% as chemical components, the remainder being Fe and incidental impurities, wherein the steel sheet includes a galvannealed layer on a surface thereof, the galvannealed layer containing Fe: 7% to 15% and Al: 0.02% to 0.30% and a remainder being Zn and incidental impurities, the percentage of exposed Zn metal of the galvannealed layer surface being 20% or more.Type: ApplicationFiled: September 20, 2012Publication date: November 20, 2014Inventors: Mai Miyata, Yoshitsugu Suzuki
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Publication number: 20140314616Abstract: Provided is a hot-rolled steel sheet having a composition containing 0.04 mass percent to 0.20 mass percent C, 0.7 mass percent to 2.3 mass percent Si, 0.8 mass percent to 2.8 mass percent Mn, 0.1 mass percent or less P, 0.01 mass percent or less S, 0.1 mass percent or less Al, and 0.008 mass percent or less N, the remainder being Fe and inevitable impurities. Internal oxides containing one or more selected from the group consisting of Si, Mn, and Fe are present at grain boundaries and in grains in a base metal. The internal oxides present at the grain boundaries in the base metal are located within 5 ?m from the surface of the base metal. The difference between the depths at which the internal oxides are formed in the cross direction of the steel sheet is 2 ?m or less.Type: ApplicationFiled: November 2, 2012Publication date: October 23, 2014Applicant: JFE STEEL CORPORATIONInventors: Mai Miyata, Yoshitsugu Suzuki, Yasunobu Nagataki, Yoshiyasu Kawasaki, Hirokazu Sugihara
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Publication number: 20140227554Abstract: A galvannealed steel sheet having high corrosion resistance after painting includes, on a mass percent basis, C: 0.05% to 0.15%, Si: 0.1% to 1.0%, Mn: 0.5% to 2.7%, Al: 1.00% or less, P: 0.025% or less, S: 0.025% or less, and Cr: 0% to 0.8% or less as chemical components, the remainder being Fe and incidental impurities, wherein the galvannealed steel sheet includes a galvannealed layer on at least one surface of a steel sheet in an amount of 20 to 120 g/m2 per side, a percentage of exposed zinc metal of the galvannealed layer surface being 20% or more and less than 80%, and an amount of internal oxidation in a region disposed not more than 5 ?m from the surface of the steel sheet is 0.02 g/m2 or more and 0.1 g/m2 or less: Si?0.68%, Cr??1.25Si+0.85, and Si>0.68%, Cr=0, wherein Si and Cr denote respective contents (mass %) of Si and Cr.Type: ApplicationFiled: September 20, 2012Publication date: August 14, 2014Applicant: JFE Steel CorporationInventors: Yoshitsugu Suzuki, Mai Miyata, Yoichi Makimizu
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Publication number: 20140174608Abstract: A method of manufacturing a high strength galvanized steel sheet has a first heating step including heating to 400° C. to 750° C. in an atmosphere containing O2: 0.1 to 20 percent and H2O: 1 to 50 percent and heating to 600° C. to 850° C. in an atmosphere containing O2: 0.01 to less than 0.1 percent and H2O: 1 to 20 percent is applied to a steel sheet, a second heating step includes holding the steel sheet in an atmosphere containing H2: 1 to 50 percent and having a dew point of 0° C. or lower at 750° C. to 900° C. for 15 to 600 s, cooling to a temperature of 450° C. to 550° C., and holding is performed at that temperature for 10 to 200 s, and a galvanization treatment is applied.Type: ApplicationFiled: June 1, 2012Publication date: June 26, 2014Applicant: JFE Steel CorporationInventors: Mai Miyata, Yoshitsugu Suzuki, Yoshiyasu Kawasaki, Tatsuya Nakagaito, Shinjiro Kaneko, Yasunobu Nagataki
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Publication number: 20120325376Abstract: A high-strength cold-rolled steel sheet having high chemical convertibility and a tensile strength of 590 MPa or more and a method for producing such a steel sheet are provided. The steel sheet contains, in terms of percent by mass, C: 0.05 to 0.3%, Si: 0.6 to 3.0%, Mn: 1.0 to 3.0%, P: 0.1% or less, S: 0.05% or less, Al: 0.01 to 1%, N: 0.01% or less, and the balance being Fe and unavoidable impurities. The coverage ratio of reduced iron on a steel sheet surface is 40% or more. In order to produce such a steel sheet, an oxidation treatment is performed after cold rolling. Subsequently, annealing is conducted in a furnace in a 1 to 10 vol % H2+balance N2 gas atmosphere with a dew point of ?25° C. or less.Type: ApplicationFiled: December 24, 2010Publication date: December 27, 2012Applicant: JFE STEEL CORPORATIONInventors: Yoichi Makimizu, Yoshitsugu Suzuki, Mai Miyata, Naoto Yoshimi, Junichiro Hirasawa, Shinji Otsuka, Hideki Nagano, Kohei Hasegawa