Patents by Inventor Tomotada Maruo
Tomotada Maruo 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: 20170022580Abstract: Provided is a spring steel that contains 0.15-0.40% carbon, 1-3.5% silicon, 0.20-2.0% manganese, 0.05-1.20% chromium, at most 0.030% phosphorus, at most 0.02% sulfur, and at least one of the following: 0.005-0.10% titanium, 0.005-0.05% niobium, and at most 0.25% vanadium. The remainder of said spring steel comprises iron and unavoidable impurities. The carbon equivalent (Ceq1) of the provided spring steel, as calculated by formula (1), is at most 0.55. Ceq1=[C]+0.108×[Si]?0.067×[Mn]+0.024×[Cr]?0.05×[Ni]+0.074×[V]??(1) (In the formula (1), each symbol in brackets represents the content (mass %) of the corresponding element.Type: ApplicationFiled: October 5, 2016Publication date: January 26, 2017Applicant: KABUSHIKI KAISHA KOBE SEIKO SHO (KOBE STEEL, LTD.)Inventors: Sayaka NAGAMATSU, Tomotada MARUO, Nao YOSHIHARA
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Patent number: 8470105Abstract: A high carbon steel wire material which is made of high carbon steel as a raw material for wire products such as steel cords, bead wires, PC steel wires and spring steel, allows for these wire products to be manufactured efficiently at a high wire drawing rate and has excellent wire drawability and a manufacturing process thereof. This high carbon steel wire material is made of a steel material having specific contents of C, Si, Mn, P, S, N, Al and O, and the Bcc-Fe crystal grains of its metal structure have an average crystal grain diameter (Dave) of 20 ?m or less and a maximum crystal grain diameter (Dmax) of 120 ?m or less, preferably an area ratio of crystal grains having a diameter of 80 ?m or more of 40% or less, an average sub grain diameter (dave) of 10 ?m or less, a maximum sub grain diameter (dmax) of 50 ?m or less and a (Dave/dave) ratio of the average crystal grain diameter (Dave) to the average sub grain diameter (dave) of 4.5 or less.Type: GrantFiled: May 15, 2009Date of Patent: June 25, 2013Assignee: Kobe Steele, Ltd.Inventors: Takuya Kochi, Shogo Murakami, Hiroshi Yaguchi, Takeshi Kuroda, Hidenori Sakai, Tomotada Maruo, Takaaki Minamida
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Patent number: 8382916Abstract: The present invention aims at providing a method for production of a steel product which surely retains scale during cooling, storage, and transportation and permits scale to scale off easily at the time of mechanical descaling and pickling that precede the secondary fabrication. The steel product is produced by heating and hot rolling a steel billet and spraying the hot-rolled steel product with steam and/or water mist having a particle diameter no larger than 100 ?m, for surface oxidation.Type: GrantFiled: June 7, 2010Date of Patent: February 26, 2013Assignee: Kobe Steel, Ltd.Inventors: Takeshi Kuroda, Hidenori Sakai, Mikako Takeda, Takuya Kochi, Takashi Onishi, Tomotada Maruo, Takaaki Minamida
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Publication number: 20120285585Abstract: A spring steel contains 0.15-0.40% carbon, 1-3.5% silicon, 0.20-2.0% manganese, 0.05-1.20% chromium, at most 0.030% phosphorus, at most 0.02% sulfur, and at least one of the following: 0.005-0.10% titanium, 0.005-0.05% niobium, and at most 0.25% vanadium. The remainder of said spring steel includes iron and unavoidable impurities. The carbon equivalent (Ceq1) of the provided spring steel, as calculated by formula (1), is at most 0.55. (1) Ceq1=[C]+0.108×[Si]?0.067×[Mn]+0.024×[Cr]?0.05×[Ni]+0.074×[V]. In the formula (1), each symbol in brackets represents the content (mass %) of the corresponding element.Type: ApplicationFiled: December 21, 2010Publication date: November 15, 2012Applicant: Kabushiki Kaisha Kobe Seiko Sho (Kobe Steel, Ltd.)Inventors: Sayaka Nagamatsu, Tomotada Maruo, Nao Yoshihara
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Patent number: 8216394Abstract: The present invention aims at providing a method for production of a steel product which surely retains scale during cooling, storage, and transportation and permits scale to scale off easily at the time of mechanical descaling and pickling that precede the secondary fabrication. The steel product is produced by heating and hot rolling a steel billet and spraying the hot-rolled steel product with steam and/or water mist having a particle diameter no larger than 100 ?m, for surface oxidation.Type: GrantFiled: August 14, 2006Date of Patent: July 10, 2012Assignee: Kobe Steel, Ltd.Inventors: Takeshi Kuroda, Hidenori Sakai, Mikako Takeda, Takuya Kochi, Takashi Onishi, Tomotada Maruo, Takaaki Minamida
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Patent number: 8092916Abstract: An FeO layer including fine crystal grains having random orientation is formed as inner layer scale on the surface of the steel wire rod containing C: 0.05-1.2 mass % (hereinafter referred to as “%”), Si: 0.01-0.50%, Mn: 0.1-1.5%, P: 0.02% or below, S: 0.02% or below, N: 0.005% or below, an Fe2SiO4 layer with the thickness: 0.01-1.0 ?m is formed in the boundary face between the FeO layer of the inner layer scale and steel, and the thickness of the inner layer scale is 1-40% of the total scale thickness. In another aspect, the maximum grain size of the crystal grain of the inner layer scale is 5.0 ?m or below and the average grain size is 2.0 ?m or below.Type: GrantFiled: March 24, 2009Date of Patent: January 10, 2012Assignee: Kobe Steel, Ltd.Inventors: Mikako Takeda, Shohei Nakakubo, Takashi Onishi, Masumi Nishimura, Hidenori Sakai, Tomotada Maruo
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Publication number: 20100236667Abstract: The present invention aims at providing a method for production of a steel product which surely retains scale during cooling, storage, and transportation and permits scale to scale off easily at the time of mechanical descaling and pickling that precede the secondary fabrication. The steel product is produced by heating and hot rolling a steel billet and spraying the hot-rolled steel product with steam and/or water mist having a particle diameter no larger than 100 ?m, for surface oxidation.Type: ApplicationFiled: June 7, 2010Publication date: September 23, 2010Applicant: Kabushiki Kaisha Kobe Seiko Sho (Kobe Steel, Ltd.)Inventors: Takeshi Kuroda, Hidenori Sakai, Mikako Takeda, Takuya Kochi, Takashi Onishi, Tomotada Maruo, Takaaki Minamida
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Publication number: 20090269578Abstract: An FeO layer including fine crystal grains having random orientation is formed as inner layer scale on the surface of the steel wire rod containing C: 0.05-1.2 mass % (hereinafter referred to as “%”), Si: 0.01-0.50%, Mn: 0.1-1.5%, P: 0.02% or below, S: 0.02% or below, N: 0.005% or below, an Fe2SiO4 layer with the thickness: 0.01-1.0 ?m is formed in the boundary face between the FeO layer of the inner layer scale and steel, and the thickness of the inner layer scale is 1-40% of the total scale thickness. In another aspect, the maximum grain size of the crystal grain of the inner layer scale is 5.0 ?m or below and the average grain size is 2.0 ?m or below.Type: ApplicationFiled: March 24, 2009Publication date: October 29, 2009Applicant: Kabushiki Kaisha Kobe Seiko Sho (Kobe Steel, Ltd.)Inventors: Mikako TAKEDA, Shohei NAKAKUBO, Takashi ONISHI, Masumi NISHIMURA, Hidenori SAKAI, Tomotada MARUO
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Publication number: 20090229710Abstract: The present invention aims at providing a method for production of a steel product which surely retains scale during cooling, storage, and transportation and permits scale to scale off easily at the time of mechanical descaling and pickling that precede the secondary fabrication. The steel product is produced by heating and hot rolling a steel billet and spraying the hot-rolled steel product with steam and/or water mist having a particle diameter no larger than 100 ?m, for surface oxidation.Type: ApplicationFiled: August 14, 2006Publication date: September 17, 2009Applicant: Kabushiki Kaisha Kobe Seiko Sho ( Kobe Steel, Ltd.)Inventors: Takeshi Kuroda, Hidenori Sakai, Mikako Takeda, Takuya Kochi, Takashi Onishi, Tomotada Maruo, Takaaki Minamida
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Publication number: 20090223610Abstract: A high carbon steel wire material which is made of high carbon steel as a raw material for wire products such as steel cords, bead wires, PC steel wires and spring steel, allows for these wire products to be manufactured efficiently at a high wire drawing rate and has excellent wire drawability and a manufacturing process thereof. This high carbon steel wire material is made of a steel material having specific contents of C, Si, Mn, P, S, N, Al and O, and the Bcc-Fe crystal grains of its metal structure have an average crystal grain diameter (Dave) of 20 ?m or less and a maximum crystal grain diameter (Dmax) of 120 ?m or less, preferably an area ratio of crystal grains having a diameter of 80 ?m or more of 40% or less, an average sub grain diameter (dave) of 10 ?m or less, a maximum sub grain diameter (dmax) of 50 ?m or less and a (Dave/dave) ratio of the average crystal grain diameter (Dave) to the average sub grain diameter (dave) of 4.5 or less.Type: ApplicationFiled: May 15, 2009Publication date: September 10, 2009Applicant: Kabushiki Kaisha Kobe Seiko Sho (Kobe Steel, Ltd.)Inventors: Takuya KOCHI, Shogo MURAKAMI, Hiroshi YAGUCHI, Takeshi KURODA, Hidenori SAKAI, Tomotada MARUO, Takaaki MINAMIDA
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Publication number: 20070277913Abstract: Disclosed are a wire rod and a method therefor. The wire rod is excellent in wire-drawing workability, insusceptible to wire break in spite of an increase in wire-drawing rate, and reduction of area, and capable of extending a die life by suppressing die wear. The wire rod is made of steel containing C: 0.6 to 1.1%, Si: 0.1 to 2.0%, Mn: 0.1 to 1%, P: not more than 0.20%, S: not more than 0.20%, N: not more than 0.006%, Al: not more than 0.03%, and O: not more than 0.003%, the balance including Fe, and unavoidable impurities. Further, the wire rod comprises a pearlite structure wherein an area ratio of a second-phase ferrite is not more than 11.0%, and a pearlite lamellar spacing is not less than 120 ?m.Type: ApplicationFiled: May 29, 2007Publication date: December 6, 2007Applicant: Kabushiki Kaisha Kobe Seiko Sho (Kobe Steel, Ltd.)Inventors: Takuya Kochi, Takeshi Kuroda, Hidenori Sakai, Tomotada Maruo, Shogo Murakami, Hiroshi Yaguchi