Patents by Inventor Yuichi Futamura
Yuichi Futamura 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: 20160355920Abstract: Provided are: a high-strength steel sheet which is improved in both elongation and local formability and thus exhibits excellent workability; and a manufacturing method thereof. The high-strength steel sheet contains C, Si, Mn, Al, P and S with the remainder including iron and unavoidable impurities, and has a metal structure which includes polygonal ferrite, bainite, tempered martensite, and retained austenite. In the metal structure, (1) the bainite has a composite microstructure including both a high-temperature-formed bainite having an average distance between adjacent regions of retained austenite and/or carbide of 1 ?m or more and a low-temperature-formed bainite having an average distance between adjacent regions of retained austenite and/or carbide of less than 1 ?m each identified upon observation with a scanning electron microscope; and (2) the retained austenite is present in a volume percentage of 5% or more of the entire metal structure as determined by a saturation magnetization measurement.Type: ApplicationFiled: August 18, 2016Publication date: December 8, 2016Applicant: KABUSHIKI KAISHA KOBE SEIKO SHO (Kobe Steel, Ltd.)Inventors: Yuichi FUTAMURA, Michiharu NAKAYA, Takayuki KIMURA
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Publication number: 20160237520Abstract: A high-strength steel sheet of the present invention is a steel sheet satisfying a predetermined component composition. A metal structure of the steel sheet is composed of polygonal ferrite, high-temperature region generated bainite, low-temperature region generated bainite and retained austenite each having a predetermined area percent, and a distribution using each average IQ of predetermined crystal grains determined by electron backscatter diffraction satisfies Equations (1) and (2) below. According to the present invention, a high-strength steel sheet having excellent formability and low-temperature toughness can be realized even at a tensile strength of 590 MPa or more. (IQave?IQmin)/(IQmax?IQmin)?0.40??(1) (?IQ)/(IQmax?IQmin)?0.Type: ApplicationFiled: September 25, 2014Publication date: August 18, 2016Applicant: KABUSHIKI KAISHA KOBE SEIKO SHO (Kobe Steel, Ltd.)Inventors: Tadao MURATA, Koji KASUYA, Sae MIZUTA, Yuichi FUTAMURA
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Publication number: 20160208359Abstract: A high-strength steel sheet of the present invention is a steel sheet satisfying a predetermined component composition. A metal structure of the steel sheet is composed of polygonal ferrite, high-temperature region generated bainite, low-temperature region generated bainite and retained austenite each having a predetermined area percent, and a distribution using each average IQ of predetermined crystal grains determined by electron backscatter diffraction satisfies Equations (1) and (2) below. According to the present invention, a high-strength steel sheet having excellent ductility and low-temperature toughness can be realized even at a tensile strength of 780 MPa or more. (IQave?IQmin)/(IQmax?IQmin)?0.40??(1) (?IQ)/(IQmax?IQmin)?0.Type: ApplicationFiled: September 25, 2014Publication date: July 21, 2016Applicant: KABUSHIKI KAISHA KOBE SEIKO SHO(KOBE STEEL, LTD.)Inventors: Koji KASUYA, Tadao MURATA, Sae MIZUTA, Yuichi FUTAMURA
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Publication number: 20150101712Abstract: Provided is a method that enables manufacture, with good productivity, of a high-strength cold-rolled steel with improved elongation (EL), stretch-flangeability (?), bendability (R), and balance of these properties (TS×EL×?/1000), outstanding composite workability as evaluated by Erichsen test, and a tensile strength of at least 980 MPa. A steel material satisfying a prescribed constituent composition is held and soaked for at least fifty seconds at a temperature at or above the Ac3 point, after which the steel material is cooled at an average cooling rate of at least 15° C./sec to a discretionary temperature (T) that satisfies expression (1) below, held for 5-180 seconds in a temperature range that satisfies expression (1) below, then heated to a temperature region that satisfies expression (2) below, held for at least 50 seconds in this temperature region, and then cooled. 300° C.?T1 (° C.)<400° C. ??(1) 400° C.?T2 (° C.)<540° C.Type: ApplicationFiled: February 28, 2013Publication date: April 16, 2015Applicant: KABUSHIKI KAISHA KOBE SEIKO SHO (KOBE STEEL, LTD.)Inventors: Yuichi Futamura, Michiharu Nakaya
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Publication number: 20150086808Abstract: A high-strength cold-rolled steel sheet has a specific chemical composition and has a steel microstructure meeting conditions: a total content of bainitic ferrite (BF) and tempered martensite (TM) is 65% (in area percent, hereinafter the same for steel microstructure) or more; a fresh martensite (M) content is 3% to 18%; a retained austenite content is 5% or more; and a polygonal ferrite (F) content is 5% or less. The steel sheet has a specific average KAM<1.00° of 0.50° or more and has a tensile strength of 980 MPa or more. The high-strength cold-rolled steel sheet excels in formability and shape fixability.Type: ApplicationFiled: March 6, 2013Publication date: March 26, 2015Applicant: KABUSHIKI KAISHA KOBE SEIKO SHO (Kobe Steel, Ltd.)Inventors: Kouji Kasuya, Yuichi Futamura, Yukihiro Utsumi
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Publication number: 20140044988Abstract: Provided are: a high-strength steel sheet which is improved in both elongation and local formability and thus exhibits excellent workability; and a manufacturing method thereof. The high-strength steel sheet contains C, Si, Mn, Al, P and S with the remainder including iron and unavoidable impurities, and has a metal structure which includes polygonal ferrite, bainite, tempered martensite, and retained austenite. In the metal structure, (1) the bainite has a composite microstructure including both a high-temperature-formed bainite having an average distance between adjacent regions of retained austenite and/or carbide of 1 ?m or more and a low-temperature-formed bainite having an average distance between adjacent regions of retained austenite and/or carbide of less than 1 ?m each identified upon observation with a scanning electron microscope; and (2) the retained austenite is present in a volume percentage of 5% or more of the entire metal structure as determined by a saturation magnetization measurement.Type: ApplicationFiled: March 21, 2012Publication date: February 13, 2014Applicant: Kabushiki Kaisha Kobe Seiko Sho (Kobe Steel Ltd.)Inventors: Yuichi Futamura, Michiharu Nakaya, Takayuki Kimura
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High-strength cold-rolled steel sheet excellent in workability and method for manufacturing the same
Patent number: 8480819Abstract: In a cold-rolled steel sheet in relation with the present invention, metallurgical structure of the steel sheet is made a mixture structure including bainite, residual austenite and tempered martensite, particularly, when the metallurgical structure is observed with a scanning electron microscope, bainite is constituted of composite structure of high temperature range forming bainite with 1 ?m or above average distance between neighboring residual austenite and/or carbide and low temperature range forming bainite with below 1 ?m average distance between neighboring residual austenite and/or carbide, and when the area ratio of the high temperature range forming bainite with respect to total metallurgical structure is made a and the total area ratio of the low temperature range forming bainite and the tempered martensite with respect to the total metallurgical structure is made b, a: 20-80%, b: 20-80%, and a+b: 70% or above are satisfied.Type: GrantFiled: January 3, 2011Date of Patent: July 9, 2013Assignee: Kobe Steel, Ltd.Inventor: Yuichi Futamura -
Patent number: 8460800Abstract: Disclosed is a cold-rolled steel sheet having a specific steel composition and having a composite steel structure including a ferrite structure and a martensite-containing second phase. In a surface region of the steel sheet from the surface to a depth one-tenth the gage, the number density of n-ary groups of inclusions determined by specific n-th determinations is 120 or less per 100 cm2 of a rolling plane, in which the distance in steel sheet rolling direction between outermost surfaces of two outermost particles of the group of inclusions is 80 ?m or more. Also disclosed is a cold-rolled steel sheet having a specific steel composition and having a steel structure of a martensite single-phase structure. In the surface region, the number density of groups of inclusions, in which the distance between the outermost surfaces is 100 ?m or more, is 120 or less per 100 cm2 of a rolling plane.Type: GrantFiled: February 18, 2010Date of Patent: June 11, 2013Assignee: Kobe Steel, Ltd.Inventors: Tetsuji Hoshika, Sae Mizuta, Yuichi Futamura, Masaaki Miura, Yukihiro Utsumi, Hiroaki Matsumoto, Hiroki Ohta
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Patent number: 8449988Abstract: A cold-rolled steel sheet has a chemical composition of C: 0.12% to 0.3%, Si: 0.5% or less, Mn: less than 1.5%, Al: 0.15% or less, N: 0.01% or less, P: 0.02% or less, and S: 0.01% or less, with the remainder including iron and inevitable impurities and has a martensite single-phase structure as its steel microstructure. In a surface region of the steel sheet from the surface to a depth one-tenth the gauge, the number density of n-ary groups of inclusions determined by specific n-th determinations is 120 or less per 100 cm2 of a rolling plane, where the distance in steel sheet rolling direction between outermost surfaces of two outermost particles of the group of inclusions is 100 ?m or more. The steel sheet is a high-strength cold-rolled steel sheet which has a sufficiently minimized rate of bending fracture starting from inclusions and thereby has excellent bending workability.Type: GrantFiled: May 3, 2011Date of Patent: May 28, 2013Assignee: Kobe Steel, Ltd.Inventors: Atsuhiro Shiraki, Sae Hamamoto, Yukihiro Utsumi, Tetsuji Hoshika, Yuichi Futamura
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Patent number: 8388771Abstract: A high strength steel sheet contains, in percent by mass, 0.03 to 0.2% of C, 0.5 to 2.5% of Si, 1 to 3.0% of Mn, 0.01 to 0.5% of Cr, 0.01 to 0.5% of Mo, 0.02 to 0.15% of Al, 0.15% or less of Ti, 0.15% or less of No, and 0.15% or less of V; wherein the remainder includes Fe and inevitable impurities, and the content of Si satisfies the following formula (1), ??4.1?[Si]??2.4??(1), provided, ?=6.9×([C]+[Mn]/6+[Cr]/5+[Mo]/4+[Ti]/15+[Nb]/17+[V]/14)1/2 is given, wherein [ ] shows the quantity (mass percent) of each element contained in the steel sheet. The high strength steel sheet is improved in formability (particularly, elongation), and excellent in balance between strength and elongation.Type: GrantFiled: September 6, 2011Date of Patent: March 5, 2013Assignee: Kobe Steel, Ltd.Inventors: Yuichi Futamura, Katsuhiro Yamamoto, Masaaki Miura
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Patent number: 8349471Abstract: A high-strength cold-rolled steel sheet with improved TS-EL balance, springback value, workability and shape freezing properties having: a steel content including 0.10-0.20 mass % C, 0.5-2.5 mass % Si, 0.5-2.25 mass % Mn, and 0.01-0.10 mass % Al; a structure comprising (A) a mother phase structure of ferrite and (B) a second phase structure of retained austenite optionally including martensite; and satisfying the following expressions (1) and (2): (Vf×V?×C?×dis)/dia?300??(1), dis?1.0 ?m??(2); where Vf (%) is the volume fraction of the ferrite, V? (%) is the volume fraction of the retained austenite, C? (mass %) is the carbon content in the retained austenite, dis (?m) is the shortest distance between the second phase structures, and dia (?m) is the average grain size of the second phase structures.Type: GrantFiled: March 5, 2010Date of Patent: January 8, 2013Assignee: Kobe Steel, Ltd.Inventors: Michitaka Tsunezawa, Yuichi Futamura, Masaaki Miura
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Publication number: 20120312433Abstract: The invention relates to a steel sheet having a tensile strength of 1180 MPa or more, which excels in workability and cold brittleness resistance. The high-strength steel sheet contains 0.10% to 0.30% of C, 1.40% to 3.0% of Si, 0.5% to 3.0% of Mn, 0.1% or less of P, 0.05% or less of S, 0.005% to 0.20% of Al, 0.01% or less of N, 0.01% or less of O, as well as Fe and inevitable impurities. The steel sheet has: (i) a ferrite volume fraction of 5% to 35% and a bainitic ferrite and/or tempered martensite volume fraction of 60% or more; (ii) a MA constituent volume fraction of 6% or less (excluding 0%); and (iii) a retained austenite volume fraction of 5% or more.Type: ApplicationFiled: June 5, 2012Publication date: December 13, 2012Applicant: Kabushiki Kaisha Kobe Seiko Sho (Kobe Steel, Ltd.)Inventors: Sae MIZUTA, Yuichi FUTAMURA, Yukihiro Utsumi
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Patent number: 8133330Abstract: A high-strength hot-dip galvanized steel sheet excellent in workability according to the present invention: contains C, Si, Mn and other elements; has a dual phase structure containing ferrite and martensite as the metallographic structure; and, in the ferrite structure, satisfies the expression 0.2?(Lb/La)?1.Type: GrantFiled: October 1, 2009Date of Patent: March 13, 2012Assignee: Kobe Steel, Ltd.Inventors: Yuichi Futamura, Masaaki Miura
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Publication number: 20110318605Abstract: A high strength steel sheet contains, in percent by mass, 0.03 to 0.2% of C, 0.5 to 2.5% of Si, 1 to 3.0% of Mn, 0.01 to 0.5% of Cr, 0.01 to 0.5% of Mo, 0.02 to 0.15% of Al, 0.15% or less of Ti, 0.15% or less of No, and 0.15% or less of V; wherein the remainder includes Fe and inevitable impurities, and the content of Si satisfies the following formula (1), ?-4.1[Si]?-2.4??(1), provided, ?=6.9×([C]+[Mn]/6+[Cr]/5+[Mo]/4+[Ti]/15+[Nb]/17+[V]/14)1/2 is given, wherein [ ] shows the quantity (mass percent) of each element contained in the steel sheet. The high strength steel sheet is improved in formability (particularly, elongation), and excellent in balance between strength and elongation.Type: ApplicationFiled: September 6, 2011Publication date: December 29, 2011Applicant: Kabushiki Kaisha Kobe Seiko Sho (Kobe Steel, Ltd.)Inventors: Yuichi FUTAMURA, Katsuhiro Yamamoto, Masaaki Miura
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Publication number: 20110287280Abstract: A cold-rolled steel sheet has a chemical composition of C: 0.12% to 0.3%, Si: 0.5% or less, Mn: less than 1.5%, Al: 0.15% or less, N: 0.01% or less, P: 0.02% or less, and S: 0.01% or less, with the remainder including iron and inevitable impurities and has a martensite single-phase structure as its steel microstructure. In a surface region of the steel sheet from the surface to a depth one-tenth the gauge, the number density of n-ary groups of inclusions determined by specific n-th determinations is 120 or less per 100 cm2 of a rolling plane, where the distance in steel sheet rolling direction between outermost surfaces of two outermost particles of the group of inclusions is 100 ?m or more. The steel sheet is a high-strength cold-rolled steel sheet which has a sufficiently minimized rate of bending fracture starting from inclusions and thereby has excellent bending workability.Type: ApplicationFiled: May 3, 2011Publication date: November 24, 2011Applicant: Kabushiki Kaisha Kobe Seiko Sho (Kobe Steel, Ltd.)Inventors: Atsuhiro SHIRAKI, Sae Hamamoto, Yukihiro Utsumi, Tetsuji Hoshika, Yuichi Futamura
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Patent number: 8025982Abstract: Disclosed is a high-strength hot dip galvannealed steel sheet having high powdering resistance produced by employing such a constitution that a Fe—Zn alloy plated layer is provided on at least one side of a basis steel sheet and a region in which Al (atomic %)/Zn (atomic %)?0.10 is present in a thickness of 300 ? or more from the surface of the plated layer along the depth direction of the plated layer. Also disclosed is a hot dip galvannealed steel sheet whose formability is greatly improved by optionally specifying chemical composition and structure of the basis steel sheet.Type: GrantFiled: December 1, 2006Date of Patent: September 27, 2011Assignee: Kobe Steel, Ltd.Inventors: Yuichi Futamura, Michitaka Tsunezawa, Masaaki Miura, Hiroshi Irie, Takatoshi Yoshida, Masafumi Shimizu
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HIGH-STRENGTH COLD-ROLLED STEEL SHEET EXCELLENT IN WORKABILITY AND METHOD FOR MANUFACTURING THE SAME
Publication number: 20110186189Abstract: In a cold-rolled steel sheet in relation with the present invention, metallurgical structure of the steel sheet is made a mixture structure including bainite, residual austenite and tempered martensite, particularly, when the metallurgical structure is observed with a scanning electron microscope, bainite is constituted of composite structure of high temperature range forming bainite with 1 ?m or above average distance between neighboring residual austenite and/or carbide and low temperature range forming bainite with below 1 ?m average distance between neighboring residual austenite and/or carbide, and when the area ratio of the high temperature range forming bainite with respect to total metallurgical structure is made a and the total area ratio of the low temperature range forming bainite and the tempered martensite with respect to the total metallurgical structure is made b, a: 20-80%, b: 20-80%, and a+b: 70% or above are satisfied.Type: ApplicationFiled: January 3, 2011Publication date: August 4, 2011Applicant: Kabushiki Kaisha Kobe Seiko Sho (Kobe Steel, Ltd.)Inventor: Yuichi FUTAMURA -
Publication number: 20100247958Abstract: A high-strength cold-rolled steel sheet according to the present invention: satisfies the requirement of a prescribed chemical composition; has a structure comprising a mother phase structure of ferrite and a second phase structure of retained austenite and martensite (the martensite may not be included); and satisfies the following expressions (1) and (2) when the volume fraction of the ferrite in the whole structure is represented by Vf (%), the volume fraction of the retained austenite in the whole structure is represented by V? (%), the carbon content in the retained austenite is represented by C? (mass %), the shortest distance between the second phase structures is represented by dis (?m), and the average grain size of the second phase structures is represented by dia (?m), (Vf×V?×C?×dis)/dia?300??(1), dis?1.0 ?m??(2).Type: ApplicationFiled: March 5, 2010Publication date: September 30, 2010Applicant: Kabushiki Kaisha Kobe Seiko Sho (Kobe Steel, Ltd.)Inventors: Michitaka TSUNEZAWA, Yuichi Futamura, Masaaki Miura
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Publication number: 20100247957Abstract: Disclosed is a cold-rolled steel sheet having a specific steel composition and having a composite steel structure including a ferrite structure and a martensite-containing second phase. In a surface region of the steel sheet from the surface to a depth one-tenth the gage, the number density of n-ary groups of inclusions determined by specific n-th determinations is 120 or less per 100 cm2 of a rolling plane, in which the distance in steel sheet rolling direction between outermost surfaces of two outermost particles of the group of inclusions is 80 ?m or more. Also disclosed is a cold-rolled steel sheet having a specific steel composition and having a steel structure of a martensite single-phase structure. In the surface region, the number density of groups of inclusions, in which the distance between the outermost surfaces is 100 ?m or more, is 120 or less per 100 cm2 of a rolling plane.Type: ApplicationFiled: February 18, 2010Publication date: September 30, 2010Applicant: Kabushiki Kaisha Kobe Seiko Sho (Kobe Steel Ltd)Inventors: Tetsuji HOSHIKA, Sae Mizuta, Yuichi Futamura, Masaaki Miura, Yukihiro Utsumi, Hiroaki Matsumoto, Hiroki Ohta
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Publication number: 20100108200Abstract: A high-strength hot-dip galvanized steel sheet excellent in workability according to the present invention: contains C, Si, Mn and other elements; has a dual phase structure containing ferrite and martensite as the metallographic structure; and, in the ferrite structure, satisfies the expression 0.2?(Lb/La)?1.Type: ApplicationFiled: October 1, 2009Publication date: May 6, 2010Applicant: Kabushiki Kaisha Kobe Seiko Sho (Kobe Steel Ltd)Inventors: Yuichi FUTAMURA, Masaaki Miura