Patents by Inventor Kaoru Kawasaki
Kaoru Kawasaki 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: 9410231Abstract: A steel sheet, including: as chemical components, by mass %, 0.05% to 0.35% of C; 0.05% to 2.0% of Si; 0.8% to 3.0% of Mn; 0.01% to 2.0% of Al; equal to or less than 0.1% of P; equal to or less than 0.05% of S; equal to or less than 0.01% of N; and the balance including iron and inevitable impurities, wherein the steel sheet comprises 50% or more of a ferrite phase, a bainite phase, and a tempered martensite phase, 3% or more of a retained austenite phase, and 50% or more of the crystal grains of the retained austenite phase satisfy Expression 1, wherein a carbon concentration at a position of center of gravity is Cgc and a carbon concentration at a grain boundary is Cgb.Type: GrantFiled: January 31, 2011Date of Patent: August 9, 2016Assignee: NIPPON STEEL & SUMITOMO METAL CORPORATIONInventors: Riki Okamoto, Natsuko Sugiura, Kohichi Sano, Chisato Wakabayashi, Naoki Yoshinaga, Kaoru Kawasaki
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Publication number: 20160145704Abstract: A hot-stamped part includes a chemical composition represented by, in mass %: C: 0.120% to 0.400%; Si: 0.005% to 2.000%; Mn or Cr, or both thereof: 1.00% to 3.00% in total; Al: 0.005% to 0.100%; B: 0.0003% to 0.0020%; P: not more than 0.030%; S: not more than 0.0100%; O: not more than 0.0070%; N: not more than 0.0070%; Ti: 0% to 0.100%; Nb: 0% to 0.100%; V: 0% to 0.100%; Ni: 0% to 2.00%; Cu: 0% to 2.00%; Mo: 0% to 0.50%; Ca or REM, or both thereof: 0% to 0.0300% in total; and the balance: Fe and impurities, and a structure represented by: an area fraction of martensite or bainite, or both thereof: not less than 95% in total; a coverage factor of prior austenite grain boundary by iron-based carbides: not more than 80%; and a number density of iron-based carbides in prior austenite grains: not less than 45/?m2.Type: ApplicationFiled: September 12, 2014Publication date: May 26, 2016Applicant: NIPPON STEEL & SUMITOMO METAL CORPORATIONInventors: Kaoru KAWASAKI, Masafumi AZUMA, Genki ABUKAWA
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Publication number: 20160130680Abstract: A cold-rolled steel sheet includes a predetermined chemical composition, and includes a structure expressed by: an area fraction of ferrite: 95% or more; an area fraction of retained austenite and an area fraction of martensite: 1% to 3% in total; a product of the area fraction of retained austenite and a carbon concentration in retained austenite: 1 or more; a value of I(111)/{I(100)+I(110)} at a region where a depth from a surface is ¼ of a thickness of the cold-rolled steel sheet when intensity of a (hkl) plane is expressed by I(hkl): 2 or less.Type: ApplicationFiled: July 1, 2014Publication date: May 12, 2016Applicant: NIPPON STEEL & SUMITOMO METAL CORPORATIONInventors: Kaoru KAWASAKI, Masaharu KAMEDA, Kohichi SANO, Riki OKAMOTO
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Publication number: 20160067760Abstract: Provided is a surface layer grain refining hot-shearing method including: heating and keeping a steel sheet in a temperature range of from Ac3 to 1400° C. to austenitize the steel sheet; subsequently shearing the steel sheet in a state in which the steel sheet is placed on a die; and quenching by rapidly cooling the sheared steel sheet, wherein a start temperature of the shearing is set to be a temperature (° C.) obtained by adding a temperature of from 30° C. to 140° C. to a previously measured Ar3 of the steel sheet.Type: ApplicationFiled: May 9, 2013Publication date: March 10, 2016Inventors: Takashi MATSUNO, Yoshihito SEKITO, Tamaki SUZUKI, Kaoru KAWASAKI, Atsushi SETO
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Publication number: 20150225830Abstract: A cold-rolled steel sheet has a predetermined chemical composition, in which a structure before and after a hot-stamping includes ferrite: 30 area % to 90 area %, martensite: 0 area % or more and less than 20 area %, pearlite: 0 area % to 10 area %, retained austenite: 5 volume % to 20 volume %, and rest structure: bainite, a hardness of the retained austenite measured with a nano indenter before and after the hot-stamping satisfies relations of H2/H1<1.1 and ?HM<20, and a relation of TS×El>20000 MPa.% is satisfied.Type: ApplicationFiled: August 5, 2013Publication date: August 13, 2015Inventors: Toshiki Nonaka, Satoshi Kato, Kaoru Kawasaki, Toshimasa Tomokiyo
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Patent number: 8979104Abstract: A structure (10) for a front section of a vehicle body in a vehicle body (1) comprising a front chamber (3) disposed on the forward side of a vehicle interior (2) is provided with the following: a pair of front side members (11), located within the front chamber, that extend in the longitudinal direction of the vehicle body; a pair of strut towers (16) disposed on either side in the width direction of the front chamber and within which front wheel suspensions are disposed; and reinforcement members (20) that link the top of each strut tower with the front side members that face the strut towers, and that extend between the strut towers and the front side members. This configuration allows a structure for a front section of a vehicle body to be provided that can efficiently improve the rigidity of the vehicle body of an automobile against torsion and against lateral bending, and that can efficiently reduce the weight of the vehicle body by means of thickness reduction using a high-strength steel plate.Type: GrantFiled: March 8, 2012Date of Patent: March 17, 2015Assignee: Nippon Steel & Sumitomo Metal CorporationInventors: Toshiyuki Niwa, Masayoshi Suehiro, Atsushi Seto, Takeshi Kawachi, Masaaki Mizumura, Seiichi Daimaru, Kaoru Kawasaki, Hatsuhiko Oikawa, Yasunobu Miyazaki, Tatsuya Sakiyama, Nobutaka Shimizu, Naoki Yoshinaga
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Publication number: 20150050519Abstract: In a hot stamped steel, when [C] represents an amount of C (mass %), [Si] represents an amount of Si (mass %), and [Mn] represents an amount of Mn (mass %), an expression of 5×[Si]+[Mn])/[C]>10 is satisfied, a metallographic structure includes 80% or more of a martensite in an area fraction, and optionally, further includes one or more of 10% or less of a pearlite in an area fraction, 5% or less of a retained austenite in a volume ratio, 20% or less of a ferrite in an area fraction, and less than 20% of a bainite in an area fraction, TS×?, which is a product of TS that is a tensile strength and ? that is a hole expansion ratio is 50000 MPa·% or more, and a hardness of the martensite measured with a nanoindenter satisfies H2/H1<1.10 and ?HM<20.Type: ApplicationFiled: January 11, 2013Publication date: February 19, 2015Inventors: Toshiki Nonaka, Satoshi Kato, Kaoru Kawasaki, Toshimasa Tomokiyo
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Publication number: 20150043962Abstract: A tailored blank for hot stamping includes a welded portion formed by butt-welding a first aluminum-plated steel sheet and a second aluminum-plated steel sheet, an Average Al concentration of a weld metal in the welded portion is in a range of 0.3 mass % to 1.5 mass %, an Ac3 point of the weld metal is 1250° C. or lower, and furthermore, an aluminum layer formed during the butt-welding is present on a surface of the welded portion.Type: ApplicationFiled: March 28, 2013Publication date: February 12, 2015Inventors: Yasunobu Miyazaki, Yasuaki Naito, Kaoru Kawasaki, Takahiro Yoshinaga
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Patent number: 8951366Abstract: A high-strength cold-rolled steel sheet includes, by mass %, C: 0.10% to 0.40%, Mn: 0.5% to 4.0%, Si: 0.005% to 2.5%, Al: 0.005% to 2.5%, Cr: 0% to 1.0%, and a balance of iron and inevitable impurities, in which an amount of P is limited to 0.05% or less, an amount of S is limited to 0.02% or less, an amount of N is limited to 0.006% or less, the microstructure includes 2% to 30% of retained austenite by area percentage, martensite is limited to 20% or less by area percentage in the microstructure, an average particle size of cementite is 0.01 ?m to 1 ?m, and 30% to 100% of the cementite has an aspect ratio of 1 to 3.Type: GrantFiled: January 26, 2011Date of Patent: February 10, 2015Assignee: Nippon Steel & Sumitomo Metal CorporationInventors: Kohichi Sano, Chisato Wakabayashi, Hiroyuki Kawata, Riki Okamoto, Naoki Yoshinaga, Kaoru Kawasaki, Natsuko Sugiura, Nobuhiro Fujita
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Publication number: 20150010775Abstract: A hot stamped steel according to the present invention satisfies an expression of (5×[Si]+[Mn])/[C]>11 when [C] represents an amount of C by mass %, [Si] represents an amount of Si by mass %, and [Mn] represents an amount of Mn by mass %, a metallographic structure after hot stamping includes 40% to 90% of a ferrite and 10% to 60% of a martensite in an area fraction, a total of an area fraction of the ferrite and an area fraction of the martensite is 60% or more, a hardness of the martensite measured with a nanoindenter satisfies an H2/H1<1.10 and ?HM<20, and TS×?, which is a product of a tensile strength TS and a hole expansion ratio ? is 50000 MPa·% or more.Type: ApplicationFiled: January 11, 2013Publication date: January 8, 2015Inventors: Toshiki Nonaka, Satoshi Kato, Kaoru Kawasaki, Toshimasa Tomokiyo
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Publication number: 20140370329Abstract: When the amount of C, the amount of Si and the amount of Mn are respectively represented by [C], [Si] and [Mn] in unit mass %, the cold rolled steel sheet satisfies a relationship of (5×[Si]+[Mn])/[C]>10, the metallographic structure contains, by area ratio, 40% to 90% of a ferrite and 10% to 60% of a martensite, further contains one or more of 10% or less of a pearlite by area ratio, 5% or less of a retained austenite by volume ratio and 20% or less of a bainite by area ratio, the hardness of the martensite measured using a nanoindenter satisfies H20/H10<1.10 and ?HM0<20, and TS×? representing the product of TS that is a tensile strength and ? that is a hole expansion ratio is 50000 MPa·% or more.Type: ApplicationFiled: January 11, 2013Publication date: December 18, 2014Inventors: Toshiki Nonaka, Satoshi Kato, Kaoru Kawasaki, Toshimasa Tomokiyo
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Publication number: 20140342185Abstract: A cold rolled steel sheet according to the present invention satisfies an expression of (5×[Si]+[Mn])/[C]>11 when [C] represents an amount of C by mass %, [Si] represents an amount of Si by mass %, and [Mn] represents an amount of Mn by mass %, a metallographic structure before hot stamping includes 40% to 90% of a ferrite and 10% to 60% of a martensite in an area fraction, a total of an area fraction of the ferrite and an area fraction of the martensite is 60% or more, a hardness of the martensite measured with a nanoindenter satisfies an H2/H1<1.10 and ?HM<20 before the hot stamping, and TS×? which is a product of a tensile strength TS and a hole expansion ratio ? is 50000 MPa·% or more.Type: ApplicationFiled: January 11, 2013Publication date: November 20, 2014Inventors: Toshiki Nonaka, Satoshi Kato, Kaoru Kawasaki, Toshimasa Tomokiyo
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Publication number: 20140199487Abstract: Exemplary embodiments of the present invention can provide a method for producing hot dip galvannealed steel sheet which exhibits high strength, high ductility, and a significant degree of alloying. Such exemplary method can be applied to, e.g., a pickled hot rolled steel sheet or an annealed and pickled cold rolled steel sheet containing between about 0.02% and about 0.2% C and between about 0.15% and about 2.5% Mn, and may include one or more procedures for rinsing the sheet, preplating the sheet with Ni, rapidly heating the sheet in a nonoxidizing atmosphere to a sheet temperature of about 430° C. to 500° C., then hot dip plating the sheet in a galvanizing bath containing between about 0.05% and about 0.2% Al, and then immediately heating the sheet rapidly for an alloying treatment. Such exemplary method can provide an improved alloying speed, improved plating appearance and better plating adhesion.Type: ApplicationFiled: December 26, 2013Publication date: July 17, 2014Applicant: NIPPON STEEL CORPORATIONInventors: KIYOKAZU ISHIZUKA, KAZUMI NISHIMURA, IKUO KIKUCHI, KAORU KAWASAKI, JUNJI HAJI
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Publication number: 20140054872Abstract: A structure (10) for a front section of a vehicle body in a vehicle body (1) comprising a front chamber (3) disposed on the forward side of a vehicle interior (2) is provided with the following: a pair of front side members (11), located within the front chamber, that extend in the longitudinal direction of the vehicle body; a pair of strut towers (16) disposed on either side in the width direction of the front chamber and within which front wheel suspensions are disposed; and reinforcement members (20) that link the top of each strut tower with the front side members that face the strut towers, and that extend between the strut towers and the front side members. This configuration allows a structure for a front section of a vehicle body to be provided that can efficiently improve the rigidity of the vehicle body of an automobile against torsion and against lateral bending, and that can efficiently reduce the weight of the vehicle body by means of thickness reduction using a high-strength steel plate.Type: ApplicationFiled: March 8, 2012Publication date: February 27, 2014Inventors: Toshiyuki Niwa, Masayoshi Suehiro, Atsushi Seto, Takeshi Kawachi, Masaaki Mizumura, Seiichi Daimaru, Kaoru Kawasaki, Hatsuhiko Oikawa, Yasunobu Miyazaki, Tatsuya Sakiyama, Nobutaka Shimizu, Naoki Yoshinaga
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Publication number: 20140037980Abstract: A hot stamped article has a component composition containing, in terms of % by mass, 0.002% to 0.1% of C, 0.01% to 0.5% of Si, 0.5% to 2.5% of Mn+Cr, 0.1% or less of P, 0.01% or less of S, 0.05% or less of t-Al, 0.005% or less of N, and 0.0005% to 0.004% of B which is optionally contained in a case where the Mn+Cr is 1.0% or more, the remainder being Fe and unavoidable impurities. The hot stamped article has a microstructure composed of, in terms of an area ratio, 0% or more and less than 90% of martensite, 10% to 100% of bainite, and less than 0.5% of unavoidable inclusion structures, or a microstructure composed of, in terms of an area ratio, 99.5% to 100% of bainitic ferrite, and less than 0.5% of unavoidable inclusion structures.Type: ApplicationFiled: May 11, 2012Publication date: February 6, 2014Inventor: Kaoru Kawasaki
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Patent number: 8617324Abstract: Exemplary embodiments of the present invention can provide a method for producing hot dip galvannealed steel sheet which exhibits high strength, high ductility, and a significant degree of alloying. Such exemplary method can be applied to, e.g., a pickled hot rolled steel sheet or an annealed and pickled cold rolled steel sheet containing between about 0.02% and about 0.2% C and between about 0.15% and about 2.5% Mn, and may include one or more procedures for rinsing the sheet, preplating the sheet with Ni, rapidly heating the sheet in a nonoxidizing atmosphere to a sheet temperature of about 430° C. to 500° C., then hot dip plating the sheet in a galvanizing bath containing between about 0.05% and about 0.2% Al, and then immediately heating the sheet rapidly for an alloying treatment. Such exemplary method can provide an improved alloying speed, improved plating appearance and better plating adhesion.Type: GrantFiled: September 13, 2012Date of Patent: December 31, 2013Assignee: Nippon Steel & Sumitomo Metal CorporationInventors: Kiyokazu Ishizuka, Kazumi Nishimura, Ikuo Kikuchi, Kaoru Kawasaki, Junji Haji
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Publication number: 20130095347Abstract: A hot-stamped steel according to the present invention includes, by mass %, C: 0.20% to 0.35%, Si: 0.1% to 0.5%, the total of at least one selected from Mn and Cr: 1% to 3%, Al: 0.005% to 0.06%, Ti: 0.002% to 0.1%, Nb: 0.002% to 0.1%, O: 0.003% to 0.007%, and a balance of iron and inevitable impurities, wherein P is limited to 0.015% or less, S is limited to 0.01% or less, N is limited to 0.004% or less, the dimensional ratio of the lengths of prior austenite grains in a rolling direction to the lengths of the prior austenite grains in the sheet thickness direction is 1.3 to 2.5, the average grain size of the prior austenite grains is 6 ?m or less, the microstructure includes 98% or more of martensite, and the tensile strength is 1470 MPa or more.Type: ApplicationFiled: June 14, 2011Publication date: April 18, 2013Inventors: Kaoru Kawasaki, Kohichi Sano, Yoshihito Sekito
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Publication number: 20130037180Abstract: A high-strength cold-rolled steel sheet includes, by mass %, C: 0.10% to 0.40%, Mn: 0.5% to 4.0%, Si: 0.005% to 2.5%, Al: 0.005% to 2.5%, Cr: 0% to 1.0%, and a balance of iron and inevitable impurities, in which an amount of P is limited to 0.05% or less, an amount of S is limited to 0.02% or less, an amount of N is limited to 0.006% or less, the microstructure includes 2% to 30% of retained austenite by area percentage, martensite is limited to 20% or less by area percentage in the microstructure, an average particle size of cementite is 0.01 ?m to 1 ?m, and 30% to 100% of the cementite has an aspect ratio of 1 to 3.Type: ApplicationFiled: January 26, 2011Publication date: February 14, 2013Applicant: NIPPON STEEL CORPORATIONInventors: Kohichi Sano, Chisato Wakabayashi, Hiroyuki Kawata, Riki Okamoto, Naoki Yoshinaga, Kaoru Kawasaki, Natsuko Sugiura, Nobuhiro Fujita
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Publication number: 20130008569Abstract: Exemplary embodiments of the present invention can provide a method for producing hot dip galvannealed steel sheet which exhibits high strength, high ductility, and a significant degree of alloying. Such exemplary method can be applied to, e.g., a pickled hot rolled steel sheet or an annealed and pickled cold rolled steel sheet containing between about 0.02% and about 0.2% C and between about 0.15% and about 2.5% Mn, and may include one or more procedures for rinsing the sheet, preplating the sheet with Ni, rapidly heating the sheet in a nonoxidizing atmosphere to a sheet temperature of about 430° C. to 500° C., then hot dip plating the sheet in a galvanizing bath containing between about 0.05% and about 0.2% Al, and then immediately heating the sheet rapidly for an alloying treatment. Such exemplary method can provide an improved alloying speed, improved plating appearance and better plating adhesion.Type: ApplicationFiled: September 13, 2012Publication date: January 10, 2013Applicant: Nippon Steel CorporationInventors: KIYOKAZU ISHIZUKA, Kazumi Nishimura, Ikuo Kikuchi, Kaoru Kawasaki, Junji Haji
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Publication number: 20120305144Abstract: A steel sheet, including: as chemical components, by mass %, 0.05% to 0.35% of C; 0.05% to 2.0% of Si; 0.8% to 3.0% of Mn; 0.01% to 2.0% of Al; equal to or less than 0.1% of P; equal to or less than 0.05% of S; equal to or less than 0.01% of N; and the balance including iron and inevitable impurities, wherein an area ratio of equal to or higher than 50% of a total of a ferrite phase, a bainite phase, and a tempered martensite phase is contained, an area ratio of equal to or higher than 3% of a retained austenite phase is contained, and crystal grains of the retained austenite phase having a number ratio of equal to or higher than 50% satisfy Expression 1, assuming carbon concentration at a position of center of gravity is Cgc and a carbon concentration at a grain boundary is Cgb.Type: ApplicationFiled: January 31, 2011Publication date: December 6, 2012Applicant: NIPPON STEEL CORPORATIONInventors: Riki Okamoto, Natsuko Sugiura, Kohichi Sano, Chisato Wakabayashi, Naoki Yoshinaga, Kaoru Kawasaki