Patents by Inventor Kazuhito Imai
Kazuhito Imai 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: 9902135Abstract: A galvanized steel sheet for hot forming, the galvanized steel sheet including a galvanized film provided on a surface of a steel sheet, wherein the steel sheet has a chemical composition consisting of, in mass %, C: 0.02% to 0.58%, Mn: 0.5% to 3.0%, sol. Al: 0.005% to 1.0%, a predetermined element(s) as necessary; Si: less than or equal to 2.0%, P: less than or equal to 0.03%, S: less than or equal to 0.004%, N: less than or equal to 0.01%, and the balance: Fe and impurities, wherein a content of Mn in a portion from an interface of the steel sheet and the galvanized film to a depth of 5 ?m is more than or equal to 0.3 mass %, wherein the galvanized film has a plating coverage of 40 g/m2 to 110 g/m2, an Al content of more than or equal to 150 mg/m2 within the galvanized film, and an Al concentration of less than or equal to 0.5 mass %, and wherein the galvanized steel sheet is used for an application in which the galvanized steel sheet is heated to 700° C. or above and is then subjected to hot forming.Type: GrantFiled: August 5, 2013Date of Patent: February 27, 2018Assignee: NIPPON STEEL & SUMITOMO METAL CORPORATIONInventors: Hiroyuki Takahashi, Kazuhito Imai, Hitomi Nishibata
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Publication number: 20150314568Abstract: A galvanized steel sheet for hot forming, the galvanized steel sheet including a galvanized film provided on a surface of a steel sheet, wherein the steel sheet has a chemical composition consisting of, in mass %, C: 0.02% to 0.58%, Mn: 0.5% to 3.0%, sol. Al: 0.005% to 1.0%, a predetermined element(s) as necessary; Si: less than or equal to 2.0%, P: less than or equal to 0.03%, S: less than or equal to 0.004%, N: less than or equal to 0.01%, and the balance: Fe and impurities, wherein a content of Mn in a portion from an interface of the steel sheet and the galvanized film to a depth of 5 ?m is more than or equal to 0.3 mass %, wherein the galvanized film has a plating coverage of 40 g/m2 to 110 g/m2, an Al content of more than or equal to 150 mg/m2 within the galvanized film, and an Al concentration of less than or equal to 0.5 mass %, and wherein the galvanized steel sheet is used for an application in which the galvanized steel sheet is heated to 700° C. or above and is then subjected to hot forming.Type: ApplicationFiled: August 5, 2013Publication date: November 5, 2015Applicant: NIPPON STEEL & SUMITOMO METAL CORPORATIONInventors: Hiroyuki TAKAHASHI, Kazuhito IMAI, Hitomi NISHIBATA
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Patent number: 9045817Abstract: A heat treated galvannealed steel material having excellent post-painting corrosion resistance and a high strength which is suitable for use as an automotive part and a method for its manufacture are provided. A galvannealed steel material having a galvannealed coating on at least one side thereof is heat treated by heating at least a portion thereof to a temperature range in which hardening is possible. The coating remaining on the surface of at least a part of the portion which underwent heat treatment has a coating weight of at least 20 g/m2 and at most 80 g/m2 per side and an Fe content of at least 15% and at most 35%, an ? phase is present in the coating, and the centerline average roughness Ra of the surface of the coating is at most 1.5 ?m.Type: GrantFiled: July 23, 2010Date of Patent: June 2, 2015Assignee: NIPPON STEEL & SUMITOMO METAL CORPORATIONInventors: Tamotsu Toki, Atsushi Tomizawa, Nobusato Kojima, Kazuya Ishii, Kazuhito Imai, Toyomitsu Nakamura, Naoaki Shimada
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Patent number: 8741075Abstract: A method of producing a hot press-formed member having good corrosion resistance comprises subjecting a zinc-based plated steel sheet to heat treatment by heating to a temperature region of 600-750° C. at a rate of temperature increase up to 600° C. of at most 50° C. per second followed by cooling to 550° C. or below to form a steel blank which has a zinc oxide layer in its uppermost surface portion and below it a zinc-iron alloy phase having an Fe content of at least 25 mass %. This steel blank is heated to a temperature of at least its Ac3 point, then press formed immediately at a temperature of at least its Ac3 point, and then rapidly cooled. The hot press-formed member has a surface region with zinc oxide and iron-zinc solid solution phases and not containing an intermetallic compound phase or a pure zinc phase.Type: GrantFiled: June 26, 2012Date of Patent: June 3, 2014Assignees: Nippon Steel & Sumitomo Metal Corporation, Toyoda Iron Works Co., Ltd.Inventors: Kazuhito Imai, Masanobu Ichikawa
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Publication number: 20130280548Abstract: A bent metal member has a body formed from a tubular metal material and has a shape which is bent two-dimensionally or three-dimensionally. The surface of the body has a Zn-based coating which contains an ? phase and which satisfies the following condition: coating weight: at most 90 g/m2 per side, Fe content: 8-35 mass %, and a surface roughness Ra prescribed by WS B 0601: at most 2.0 ?m. The bent metal member can have a closed cross section, an open cross section, or a shaped cross section.Type: ApplicationFiled: June 19, 2013Publication date: October 24, 2013Inventors: Toyomitsu NAKAMURA, Atsushi Tomizawa, Naoaki Shimada, Nobusato Kojima, Kazuya Ishii, Kazuhito Imai, Tamotsu Toki
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Patent number: 8490457Abstract: A method of manufacturing a bent metal member comprises supporting the outer surface of a tubular metal material having a Zn-Fe alloy coating layer at two locations spaced in the axial direction of the metal material. The metal material is fed in its axial direction and heated at a position between the two locations to a temperature range of at least the Ac3 point at a heating speed such that the rate of temperature increase is at least 3.0×102° C. per second, held so that the time for which the surface of the metal material is at a temperature of 8.0×102° C. or higher is at most 2 seconds, and then rapid cooled. A bending moment is imparted to the healed portion in two or three dimensions to manufacture a bent metal member having on its surface a Zn-based layer which contains an ?, phase.Type: GrantFiled: July 19, 2011Date of Patent: July 23, 2013Assignee: Nippon Steel & Sumitomo Metal CorporationInventors: Toyomitsu Nakamura, Atsushi Tomizawa, Naoaki Shimada, Nobusato Kojima, Kazuya Ishii, Kazuhito Imai, Tamotsu Toki
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Publication number: 20120325377Abstract: A method of producing a hot press-formed member having good corrosion resistance comprises subjecting a zinc-based plated steel sheet to heat treatment by heating to a temperature region of 600-750° C. at a rate of temperature increase up to 600° C. of at most 50° C. per second followed by cooling to 550° C. or below to form a steel blank which has a zinc oxide layer in its uppermost surface portion and below it a zinc-iron alloy phase having an Fe content of at least 25 mass %. This steel blank is heated to a temperature of at least its Ac3 point, then press formed immediately at a temperature of at least its Ac3 point, and then rapidly cooled. The hot press-formed member has a surface region with zinc oxide and iron-zinc solid solution phases and not containing an intermetallic compound phase or a pure zinc phase.Type: ApplicationFiled: June 26, 2012Publication date: December 27, 2012Applicants: TOYODA IRON WORKS CO., LTD., SUMITOMO METAL INDUSTRIES, LTD.Inventors: Kazuhito IMAI, Masanobu Ichikawa
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Publication number: 20120009435Abstract: A bent metal member which is obtained by bending accompanied by heat treatment of a zinc-based coated metal material and which is suitable for use in components of automobiles due to having a high strength and excellent post-painting corrosion resistance is manufactured. The outer surface of a tubular metal material having on its surface a Zn—Fe alloy coating layer with a coating weight of 30-90 g/m2 per side, an Fe content of 8-20%, and a surface roughness Ra of at most 0.8 ?m is supported at two locations spaced in the axial direction of the metal material so that the material can move in its axial direction, the metal material is heated between the two locations to a temperature range of at least the Ac3 point at a heating speed such that the rate of temperature increase is at least 3.0×102° C. per second while feeding the metal material in its axial direction, holding so that the length of time for which the surface of the metal material is at 8.0×102° C.Type: ApplicationFiled: July 19, 2011Publication date: January 12, 2012Applicant: SUMITOMO METAL INDUSTRIES, LTD.Inventors: Toyomitsu NAKAMURA, Atsushi TOMIZAWA, Naoaki SHIMADA, Nobusato KOJIMA, Kazuya ISHII, Kazuhito IMAI, Tamotsu TOKI
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Publication number: 20110048585Abstract: A heat treated galvannealed steel material having excellent post-painting corrosion resistance and a high strength which is suitable for use as an automotive part and a method for its manufacture are provided. A galvannealed steel material having a galvannealed coating on at least one side thereof is heat treated by heating at least a portion thereof to a temperature range in which hardening is possible. The coating remaining on the surface of at least a part of the portion which underwent heat treatment has a coating weight of at least 20 g/m2 and at most 80 g/m2 per side and an Fe content of at least 15% and at most 35%, an ? phase is present in the coating, and the centerline average roughness Ra of the surface of the coating is at most 1.5 ?m.Type: ApplicationFiled: July 23, 2010Publication date: March 3, 2011Inventors: Tamotsu Toki, Atsushi Tomizawa, Nobusato Kojima, Kazuya Ishii, Kazuhito Imai, Toyomitsu Nakamura, Naoaki Shimada
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Patent number: 7673485Abstract: Hot press forming of a steel material is made possible by coating the surface of the steel material with a plated layer of zinc or a zinc alloy and forming thereon a barrier layer which prevents the vaporization of zinc even when heated to 700-1000° C. Corrosion resistance can also be guaranteed without requiring post treatment, and hot press forming of high tensile steel sheet and stainless steel sheet is made possible. The barrier layer is formed by forming an upper plated layer, by surface oxidation, by contact with an oxidizing agent, by contact with Zn and an oxidizing agent, by anodic electrolysis, by cathodic electrolysis, or by coating with a ZnO sol.Type: GrantFiled: July 22, 2005Date of Patent: March 9, 2010Assignee: Sumitomo Metal Industries, Ltd.Inventors: Kazuhito Imai, Tamotsu Toki, Yukihiro Yoshikawa, Masaru Takahashi, Toshinobu Nishibata, Nobusato Kojima
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Patent number: 7399535Abstract: A hot press-formed article having improved corrosion resistance and coating adhesion when coated is obtained by hot press forming of a zinc-based plated steel material. It has a zinc-based plating layer comprising an iron-zinc solid solution phase and atop it a zinc oxide layer. The average thickness of the zinc oxide layer which is the outermost layer is at most 2 ?m. A hot press-formed article having a good appearance and excellent corrosion resistance, coating adhesion, post-coating corrosion resistance, and weldability has a layer (2) consisting essentially of an iron-zinc solid solution phase atop a base material steel sheet (1). It also has a zinc oxide layer (3) with an average thickness of at most 5 ?m as an uppermost layer, but it does not have a substantial amount of an iron-zinc intermetallic compound phase. The total amount of Al contained in the iron-zinc solid solution layer (2) and the zinc oxide layer (3) is at most 0.Type: GrantFiled: October 21, 2005Date of Patent: July 15, 2008Assignees: Sumitomo Metal Industries, Ltd., Toyota Jodosha Kabushiki Kaisha, Toyoda Iron Works Co., Ltd.Inventors: Yukihiro Yoshikawa, Kazuhito Imai, Kunihiro Fukui, Tamotsu Toki, Shuntaro Sudo, Akira Obayashi, Masanobu Ichikawa
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Publication number: 20060121305Abstract: A hot press-formed article having improved corrosion resistance and coating adhesion when coated is obtained by hot press forming of a zinc-based plated steel material. It has a zinc-based plating layer comprising an iron-zinc solid solution phase and atop it a zinc oxide layer. The average thickness of the zinc oxide layer which is the outermost layer is at most 2 ?m. A hot press-formed article having a good appearance and excellent corrosion resistance, coating adhesion, post-coating corrosion resistance, and weldability has a layer (2) consisting essentially of an iron-zinc solid solution phase atop a base material steel sheet (1). It also has a zinc oxide layer (3) with an average thickness of at most 5 ?m as an uppermost layer, but it does not have a substantial amount of an iron-zinc intermetallic compound phase. The total amount of Al contained in the iron-zinc solid solution layer (2) and the zinc oxide layer (3) is at most 0.Type: ApplicationFiled: October 21, 2005Publication date: June 8, 2006Inventors: Yukihiro Yoshikawa, Kazuhito Imai, Kunihiro Fukui, Tamotsu Toki, Shuntaro Sudo, Akira Obayashi, Masanobu Ichikawa
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Publication number: 20050252262Abstract: Hot press forming of a steel material is made possible by coating the surface of the steel material with a plated layer of zinc or a zinc alloy and forming thereon a barrier layer which prevents the vaporization of zinc even when heated to 700-1000° C. Corrosion resistance can also be guaranteed without requiring post treatment, and hot press forming of high tensile steel sheet and stainless steel sheet is made possible. The barrier layer is formed by forming an upper plated layer, by surface oxidation, by contact with an oxidizing agent, by contact with Zn and an oxidizing agent, by anodic electrolysis, by cathodic electrolysis, or by coating with a ZnO sol.Type: ApplicationFiled: July 22, 2005Publication date: November 17, 2005Inventors: Kazuhito Imai, Tamotsu Toki, Yukihiro Yoshikawa, Masaru Takahashi, Toshinobu Nishibata, Nobusato Kojima
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Publication number: 20040166360Abstract: Hot press forming of a steel material is made possible by coating the surface of the steel material with a plated layer of zinc or a zinc alloy and forming thereon a barrier layer which prevents the vaporization of zinc even when heated to 700-1000° C. Corrosion resistance can also be guaranteed without requiring post treatment, and hot press forming of high tensile steel sheet and stainless steel sheet is made possible. The barrier layer is formed by forming an upper plated layer, by surface oxidation, by contact with an oxidizing agent, by contact with Zn and an oxidizing agent, by anodic electrolysis, by cathodic electrolysis, or by coating with a ZnO sol.Type: ApplicationFiled: December 10, 2003Publication date: August 26, 2004Inventors: Kazuhito Imai, Tamotsu Toki, Yukihiro Yoshikawa, Masaru Takahashi, Toshinobu Nishibata, Nobusato Kojima