Patents by Inventor Naoto Yoshimi
Naoto Yoshimi 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: 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: 8911574Abstract: A method for manufacturing high-Si cold rolled steel sheets includes heating a cold rolled steel sheet with a direct flame burner (A) having an air ratio of not more than 0.89 when the temperature of the cold rolled steel sheet that is being increased is in the temperature range of not less than 300° C. and less than Ta° C., subsequently heating the cold rolled steel sheet with a direct flame burner (B) having an air ratio of not less than 0.95 when the temperature of the cold rolled steel sheet is in the temperature range of not less than Ta° C. and less than Tb° C., and subsequently soak-annealing the cold rolled steel sheet in a furnace having an atmospheric gas composition which has a dew point of not more than ?25° C. and contains 1 to 10 volume % of H2 and the balance of N2.Type: GrantFiled: March 28, 2011Date of Patent: December 16, 2014Assignee: JFE Steel CorporationInventors: Shinji Ootsuka, Junichiro Hirasawa, Hideyuki Takahashi, Naoto Yoshimi, Hideki Nagano
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Patent number: 8668789Abstract: A method for the manufacturing of high strength cold rolled steel sheets includes continuously annealing a cold rolled steel sheet that has a composition containing C: 0.05-0.3% mass, Si: 0.6-3.0% mass, Mn: 1.0-3.0% mass, P: ?0.1% mass, S: ?0.02% mass, Al: 0.01-1% mass, N: ?0.01% mass, and Fe and inevitable impurities: balance, in a manner such that the cold rolled steel sheet is heated in a furnace using an oxidizing burner to a steel sheet temperature of ?700° C., then soak-annealed in a reducing atmosphere furnace at 750-900° C., then cooled so the average cooling rate between 500° C. and 100° C. is ?50° C./s. High-Si cold rolled steel sheets with high strength and good phosphatability while containing Si?0.6% are obtained without controlling conditions so as to increase the dew point in the reducing atmosphere in the soaking furnace or to increase the vapor hydrogen partial pressure ratio.Type: GrantFiled: July 27, 2010Date of Patent: March 11, 2014Assignee: JFE Steel CorporationInventors: Junichiro Hirasawa, Naoto Yoshimi, Hiroki Nakamaru, Kohei Hasegawa, Hideyuki Tsurumaru, Keita Yonetsu, Hideyuki Takahashi, Masato Sasaki
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Patent number: 8623514Abstract: A zinc-based metal plated steel sheet is excellent in tribological properties during press forming. An oxide layer containing crystalline 3Zn(OH)2.ZnSO4.xH2O is formed on a plated surface. The oxide layer has a thickness of 10 nm or more. The crystalline oxide layer is composed of 3Zn(OH)2.ZnSO4.3-5H2O.Type: GrantFiled: December 8, 2011Date of Patent: January 7, 2014Assignee: JFE Steel CorporationInventors: Yoichi Makimizu, Sakae Fujita, Naoto Yoshimi, Masahiko Tada, Shinji Ootsuka, Hiroyuki Masuoka, Katsuya Hoshino, Hiroshi Kajiyama, Masayasu Nagoshi, Wataru Tanimoto, Kyoko Fujimoto
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Publication number: 20130048157Abstract: A method for manufacturing high-Si cold rolled steel sheets includes heating a cold rolled steel sheet with a direct flame burner (A) having an air ratio of not more than 0.89 when the temperature of the cold rolled steel sheet that is being increased is in the temperature range of not less than 300° C. and less than Ta° C., subsequently heating the cold rolled steel sheet with a direct flame burner (B) having an air ratio of not less than 0.95 when the temperature of the cold rolled steel sheet is in the temperature range of not less than Ta° C. and less than Tb° C., and subsequently soak-annealing the cold rolled steel sheet in a furnace having an atmospheric gas composition which has a dew point of not more than ?25° C. and contains 1 to 10 volume % of H2 and the balance of N2.Type: ApplicationFiled: March 28, 2011Publication date: February 28, 2013Applicant: JFE STEEL CORPORATIONInventors: Shinji Ootsuka, Junichiro Hirasawa, Hideyuki Takahashi, Naoto Yoshimi, Hideki Nagano
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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
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Publication number: 20120301709Abstract: A hot dip galvannealed steel sheet, which is a plated steel sheet, the plated sheet including an oxide layer being formed on the surface of the plated steel sheet, having an average thickness of 10 nm or more, and containing Zn and at least one element selected from the group consisting of Zr, Ti and Sn.Type: ApplicationFiled: August 9, 2012Publication date: November 29, 2012Applicant: JFE STEEL CORPRATIONInventors: Hiroyuki MASUOKA, Shoichiro TAIRA, Yoshiharu SUGIMOTO, Naoto YOSHIMI, Masayasu NAGOSHI, Wataru TANIMOTO
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Patent number: 8268095Abstract: A method of manufacturing a hot dip galvannealed steel sheet, including the steps of: subjecting a steel sheet to hot dip galvanizing to manufacture a hot dip galvanized steel sheet; heating the hot dip galvanized steel sheet for alloying; subjecting the hot dip galvanized steel sheet to temper rolling; bringing the temper-rolled hot dip galvanized steel sheet into contact with an acid solution containing at least one ion selected from the group consisting of Zr ions, Ti ions, and Sn ions to thereby form an acid solution film on the surface of the steel sheet; after completion of the contact, a state where the acid solution film is formed on the surface of the steel sheet is held for at least 1 second; and washing with water the hot dip galvanized steel sheet after holding, to thereby form a Zn oxide layer having a thickness of 10 nm or more on the surface of the galvanized steel sheet.Type: GrantFiled: April 26, 2007Date of Patent: September 18, 2012Assignee: JFE Steel CorporationInventors: Hiroyuki Masuoka, Shoichiro Taira, Yoshiharu Sugimoto, Naoto Yoshimi, Masayasu Nagoshi, Wataru Tanimoto
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Publication number: 20120186707Abstract: A method for the manufacturing of high strength cold rolled steel sheets includes continuously annealing a cold rolled steel sheet that has a composition containing C: 0.05-0.3% mass, Si: 0.6-3.0% mass, Mn: 1.0-3.0% mass, P: 0.1% mass, S: ?0.02% mass, Al: 0.01-1% mass, N: ?0.01% mass, and Fe and inevitable impurities: balance, in a manner such that the cold rolled steel sheet is heated in a furnace using an oxidizing burner to a steel sheet temperature of ?700° C., then soak-annealed in a reducing atmosphere furnace at 750-900° C., then cooled so the average cooling rate between 500° C. and 100° C. is ?50° C./s. High-Si cold rolled steel sheets with high strength and good phosphatability while containing Si?0.6% are obtained without controlling conditions so as to increase the dew point in the reducing atmosphere in the soaking furnace or to increase the vapor hydrogen partial pressure ratio.Type: ApplicationFiled: July 27, 2010Publication date: July 26, 2012Applicant: JFE STEEL CORPORATIONInventors: Junichiro Hirasawa, Naoto Yoshimi, Hiroki Nakamaru, Kohei Hasegawa, Hideyuki Tsurumaru, Keita Yonetsu, Hideyuki Takahashi, Masato Sasaki
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Patent number: 8221900Abstract: A zinc-based metal plated steel sheet is excellent in tribological properties during press forming. An oxide layer containing crystalline 3Zn(OH)2·ZnSO4·xH2O is formed on a plated surface. The oxide layer has a thickness of 10 nm or more. The crystalline oxide layer is composed of 3Zn(OH)2·ZnSO4·3-5H2O.Type: GrantFiled: September 3, 2008Date of Patent: July 17, 2012Assignee: JFE Steel CorporationInventors: Yoichi Makimizu, Sakae Fujita, Naoto Yoshimi, Masahiko Tada, Shinji Ootsuka, Hiroyuki Masuoka, Katsuya Hoshino, Hiroshi Kajiyama, Masayasu Nagoshi, Wataru Tanimoto, Kyoko Fujimoto
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Publication number: 20120082845Abstract: A zinc-based metal plated steel sheet is excellent in tribological properties during press forming. An oxide layer containing crystalline 3Zn(OH)2.ZnSO4. xH2O is formed on a plated surface. The oxide layer has a thickness of 10 nm or more. The crystalline oxide layer is composed of 3Zn(OH)2.ZnSO4.3-5H2O.Type: ApplicationFiled: December 8, 2011Publication date: April 5, 2012Applicant: JFE Steel CorporationInventors: Yoichi Makimizu, Sakae Fujita, Naoto Yoshimi, Masahiko Tada, Shinji Ootsuka, Hiroyuki Masuoka, Katsuya Hoshino, Hiroshi Kajiyama, Masayasu Nagoshi, Wataru Tanimoto, Kyoko Fujimoto
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Publication number: 20110236677Abstract: A method for producing a galvanized steel sheet includes contacting a steel sheet with a zinc-containing aqueous solution having a zinc ion concentration of 1 to 100 g/l, contacting the steel sheet with an aqueous solution with a pH of 6 to 14, washing the steel sheet with water, and then drying the steel sheet. An example of the zinc-containing aqueous solution is a solution containing zinc sulfate. According to the method, an oxide layer which has an average thickness of 10 nm or more and which principally contains zinc is formed on the steel sheet and the galvanized steel sheet can be stably produced at high speed in a reduced space so as to have excellent press formability.Type: ApplicationFiled: April 22, 2009Publication date: September 29, 2011Applicant: JFE STEEL CORPORATIONInventors: Yoichi Makimizu, Hiroshi Kajiyama, Sakae Fujita, Naoto Yoshimi, Masahiko Tada, Shinji Ootsuka, Hiroyuki Masuoka, Katsuya Hoshino
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Publication number: 20110226387Abstract: A method for manufacturing a galvanized steel sheet, includes: galvanizing a steel sheet; bringing the surface of the steel sheet into contact with an aqueous solution containing zinc ion in the range of 5 to 100 g/l as the zinc ion concentration, having a pH of 4 to 6, and having a liquid temperature of 20 to 70° C., holding the steel sheet for 1 to 60 seconds; and then washing and drying the steel sheet. The solution containing zinc is preferably one containing zinc sulfate, for example. According to the method, a galvanized steel sheet having an oxide layer having an average thickness of 10 nm or more and mainly containing zinc formed on the surface of the steel sheet and having excellent press formability can be stably manufactured in a short time.Type: ApplicationFiled: April 22, 2009Publication date: September 22, 2011Applicant: JFE STEEL CORPORATIONInventors: Yoichi Makimizu, Hiroshi Kajiyama, Sakae Fujita, Naoto Yoshimi, Masahiko Tada, Hiroyuki Masuoka, Katsuya Hoshino, Masayasu Nagoshi
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Patent number: 8012599Abstract: The surface-treated steel sheet has a zinc-based plated steel sheet, a surface-treatment coating being formed on the surface of the zinc-based steel sheet by applying and drying a surface treatment coating composition thereon, and a top coating being formed by applying and drying a coating composition for top coating on the surface-treatment coating. The surface treatment coating composition contains a water-epoxy resin dispersion, a silane coupling agent, and phosphoric acid and/or a hexafluorometal acid. The coating composition for top coating contains a high molecular weight epoxy group-containing resin having number average molecular weights ranging from 6000 to 20000.Type: GrantFiled: October 26, 2007Date of Patent: September 6, 2011Assignees: JFE Steel Corporation, Kansai Paint Co., Ltd.Inventors: Tatsuya Miyoshi, Kenichi Sasaki, Naoto Yoshimi, Akira Matsuzaki, Kazuhisa Okai, Takao Ooshima, Takashi Nakano, Masahiro Murata, Syoichi Tanaka
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Publication number: 20100255341Abstract: A zinc-based metal plated steel sheet is excellent in tribological properties during press forming. An oxide layer containing crystalline 3Zn(OH)2.ZnSO4.xH2O is formed on a plated surface. The oxide layer has a thickness of 10 nm or more. The crystalline oxide layer is composed of 3Zn(OH)2.ZnSO4.3-5H2O.Type: ApplicationFiled: September 3, 2008Publication date: October 7, 2010Applicant: JFE STEEL CORPORATIONInventors: Yoichi Makimizu, Sakae Fujita, Naoto Yoshimi, Masahiko Tada, Shinji Ootsuka, Hiroyuki Masuoka, Katsuya Hoshino, Hiroshi Kajiyama, Masayasu Nagoshi, Wataru Tanimoto, Kyoko Fujimoto
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Publication number: 20090239063Abstract: A method of manufacturing a hot dip galvannealed steel sheet, including the steps of: subjecting a steel sheet to hot dip galvanizing to manufacture a hot dip galvanized steel sheet; heating the hot dip galvanized steel sheet for alloying; subjecting the hot dip galvanized steel sheet to temper rolling; bringing the temper-rolled hot dip galvanized steel sheet into contact with an acid solution containing at least one ion selected from the group consisting of Zr ions, Ti ions, and Sn ions to thereby form an acid solution film on the surface of the steel sheet; after completion of the contact, a state where the acid solution film is formed on the surface of the steel sheet is held for at least 1 second; and washing with water the hot dip galvanized steel sheet after holding, to thereby form a Zn oxide layer having a thickness of 10 nm or more on the surface of the galvanized steel sheet.Type: ApplicationFiled: April 26, 2007Publication date: September 24, 2009Applicant: JFE STEEL CORPORATIONInventors: Hiroyuki Masuoka, Shoichiro Taira, Yoshiharu Sugimoto, Naoto Yoshimi, Masayasu Nagoshi, Wataru Tanimoto
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Patent number: 7517591Abstract: The surface-treated steel sheet has a zinc-based plated steel sheet, a surface-treatment coating being formed on the surface of the zinc-based steel sheet by applying and drying a surface treatment coating composition thereon, and a top coating being formed by applying and drying a coating composition for top coating on the surface-treatment coating. The surface treatment coating composition contains a water-epoxy resin dispersion, a silane coupling agent, and phosphoric acid and/or a hexafluorometal acid. The coating composition for top coating contains a high molecular weight epoxy group-containing resin having number average molecular weights ranging from 6000 to 20000.Type: GrantFiled: June 14, 2004Date of Patent: April 14, 2009Assignees: JFE Steel Corporation, Kansai Paint Co., Ltd.Inventors: Tatsuya Miyoshi, Kenichi Sasaki, Naoto Yoshimi, Akira Matsuzaki, Kazuhisa Okai, Takao Ooshima, Takashi Nakano, Masahiro Murata, Syoichi Tanaka
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Publication number: 20080070018Abstract: A surface-treated steel sheet has a zinc-based or an aluminum-based plated steel sheet, a surface-treatment coating being formed on the surface of the zinc-based or aluminum-based steel sheet by applying and drying a surface treatment coating composition thereon, and a top coating being formed by applying and drying a coating composition for top coating on the surface-treatment coating. The surface treatment coating composition contains a water-epoxy resin dispersion, a water dispersed polyurethane resin, a silane coupling agent, and phosphoric acid and/or a hexafluorometal acid. The coating composition for a top coating contains a high molecular weight epoxy group-containing resin average molecular weight of 6,000 to 20,000.Type: ApplicationFiled: October 26, 2007Publication date: March 20, 2008Applicants: JFE STEEL CORPORATION, KANSAI PAINT CO., LTD.Inventors: Tatsuya Miyoshi, Kenichi Sasaki, Naoto Yoshimi, Akira Matsuzaki, Kazuhisa Okai, Takao Ooshima, Takashi Nakano, Masahiro Murata, Syoichi Tanaka
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Patent number: 7291402Abstract: The invention is to provide a surface-treated steel sheet of good white rust resistance with no chromium in its surface treatment film, and it has realized a surface-treated steel sheet of higher-level corrosion resistance by forming a reaction layer of plating metal with a barrier layer effective for anticorrosion not in a two-layered film but in a single-layered film.Type: GrantFiled: February 14, 2003Date of Patent: November 6, 2007Assignees: JFE Steel Corporation, Kansai Paint Co., Ltd.Inventors: Okai Kazuhisa, Akira Matsuzaki, Naoto Yoshimi, Takahiro Kubota, Masaaki Yamashita, Hisato Noro, Haruo Nakamichi, Kaoru Sato, Hiroyasu Matsuki, Reijiro Nishida, Masahiro Murata, Shoichi Tanaka, Yoshikazu Morohoshi, Shingo Amaki
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Patent number: RE45821Abstract: A zinc-based metal plated steel sheet is excellent in tribological properties during press forming. An oxide layer containing crystalline 3Zn(OH)2·ZnSO4·xH2O is formed on a plated surface. The oxide layer has a thickness of 10 nm or more. The crystalline oxide layer is composed of 3Zn(OH)2·ZnSO4·3-5H2O.Type: GrantFiled: June 30, 2014Date of Patent: December 22, 2015Assignee: JFE Steel CorporationInventors: Yoichi Makimizu, Sakae Fujita, Naoto Yoshimi, Masahiko Tada, Shinji Ootsuka, Hiroyuki Masuoka, Katsuya Hoshino, Hiroshi Kajiyama, Masayasu Nagoshi, Wataru Tanimoto, Kyoko Fujimoto