Patents by Inventor Shohei YABU
Shohei YABU 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: 11939650Abstract: A hot-rolled steel sheet includes, as chemical composition, C, Si, Mn, and sol.Al. In the hot-rolled steel sheet, an average of pole densities in crystal orientation group consisting of {110}<110> to {110}<001> in surface region is 0.5 to 3.0, a standard deviation of the pole densities in the crystal orientation group is 0.2 to 2.0, and the tensile strength is 780 to 1370 MPa.Type: GrantFiled: November 20, 2019Date of Patent: March 26, 2024Assignee: NIPPON STEEL CORPORATIONInventors: Shohei Yabu, Kunio Hayashi, Yuji Yamaguchi, Marina Mori, Naoki Inoue, Genki Abukawa
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Publication number: 20240068066Abstract: There is provided a steel sheet having a chemical composition comprising, in mass %, C: 0.05 to 0.25%, Si: 0.2 to 2.0%, Mn: 1.2 to 3.0%, P: 0.030% or less, S: 0.050% or less, Al: 0.01 to 0.55%, N: 0.0100% or less, and Ti: 0.010 to 0.250%, with the balance: Fe and impurities, wherein a random intensity ratio of a texture in a near-surface portion of the steel sheet is 8.0 or less, and a minimum angle formed between a maximum strength orientation in a {110} pole figure of the texture and a normal direction of a rolled surface of the steel sheet is 10° or less.Type: ApplicationFiled: February 22, 2022Publication date: February 29, 2024Applicant: NIPPON STEEL CORPORATIONInventors: Yasuaki TANAKA, Shohei YABU, Hiroshi SHUTO, Koutarou HAYASHI, Takashi YASUTOMI, Eisaku SAKURADA
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Publication number: 20230304112Abstract: This hot rolled steel sheet has a predetermined chemical composition, in which the microstructure contains, by area%, polygonal ferrite: 2.0% or more and less than 10.0% and the remainder in the microstructure: more than 90.0% and 98.0% or less, and a correlation value that is obtained by analyzing the remainder in the microstructure in a SEM image of the microstructure is 0.82 to 0.95, and a maximum probability value is 0.0040 to 0.0200.Type: ApplicationFiled: July 9, 2021Publication date: September 28, 2023Applicant: NIPPON STEEL CORPORATIONInventors: Shohei YABU, Kazumasa TSUTSUI, Takuya KUWAYAMA
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Publication number: 20230107809Abstract: This hot-rolled steel sheet has a predetermined chemical composition, the microstructure includes, by volume percentage, 70% or more of martensite, tempered martensite, and bainite in total and 5% to 20% of residual austenite, in a surface layer region that is a range from a surface to a position at 1/10 of a sheet thickness, a sum of an average pole density of an orientation group consisting of {211}<111> to {111}<112> and a pole density of a crystal orientation of {110}<001> is 6.0 or less, a concentration of solid solution carbon in the residual austenite is 0.5 mass % or more, and a tensile strength is 980 MPa or more.Type: ApplicationFiled: February 19, 2021Publication date: April 6, 2023Applicant: NIPPON STEEL CORPORATIONInventors: Genki ABUKAWA, Masafumi AZUMA, Shohei YABU
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Publication number: 20230002848Abstract: This hot-rolled steel sheet has a predetermined chemical composition, a microstructure includes 80% or more of tempered martensite by a volume percentage and a remainder consisting of one or more of ferrite, pearlite, bainite, fresh martensite, and residual austenite, the tempered martensite includes 5×109 pieces/mm3 or more of precipitates containing Ti and having an equivalent circle diameter of 5 nm or less per unit volume, in a surface layer region that is a range from a surface to a 1/10 position of a sheet thickness, a sum of an average pole density of a crystal orientation group consisting of {211}<111> to {111}<112> and a pole density in a crystal orientation of {110}<001> is 6.0 or less, and a tensile strength is 980 MPa or more.Type: ApplicationFiled: December 15, 2020Publication date: January 5, 2023Applicant: NIPPON STEEL CORPORATIONInventors: Genki ABUKAWA, Masafumi AZUMA, Eisaku SAKURADA, Shohei YABU
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Publication number: 20220389545Abstract: A hot-rolled steel sheet includes, as chemical composition, C, Si, Mn, and sol.Al. In the hot-rolled steel sheet, an average of pole densities in crystal orientation group consisting of {110}<110> to {110}<001> in surface region is 0.5 to 3.0, a standard deviation of the pole densities in the crystal orientation group is 0.2 to 2.0, and the tensile strength is 780 to 1370 MPa.Type: ApplicationFiled: November 20, 2019Publication date: December 8, 2022Applicant: NIPPON STEEL CORPORATIONInventors: Shohei YABU, Kunio HAYASHI, Yuji YAMAGUCHI, Marina MORI, Naoki INOUE, Genki ABUKAWA
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Publication number: 20220380876Abstract: This hot-rolled steel sheet has a predetermined chemical composition, in a microstructure at a 1/4 position of a sheet thickness in a sheet thickness direction from a surface, by area ratios, a primary phase is 95.00% to 98.00% of bainite, a secondary phase is 2.00% to 5.00% of tempered martensite, an average grain size of the secondary phase is 1.5 ?m or less, a pole density in a (110)<112> orientation is 3.0 or less, an average grain size of an iron-based carbide is 0.100 ?m or less, in a microstructure from the surface to a 1/16 position of the sheet thickness in the sheet thickness direction from the surface, a pole density in a (110)<1-11> orientation is 3.0 or less, and a tensile, strength TS is 980 MPa or more.Type: ApplicationFiled: December 8, 2020Publication date: December 1, 2022Applicant: NIPPON STEEL CORPORATIONInventors: Daisuke ITO, Shohei YABU, Takeshi TOYODA
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Publication number: 20220372588Abstract: This hot-rolled steel sheet has a predetermined chemical composition, in a microstructure at a ¼ position of a sheet thickness in a sheet thickness direction from a surface, a primary phase is bainite, a secondary phase is martensite or a martensite-austenite mixed phase, an average grain size of the secondary phase is 1.5 ?m or less, an average grain size of particles having grain diameters that are largest 10% or less out of all particles in the secondary phase is 2.5 ?m or less, a pole density in a (110)<112> orientation is 3.0 or less, and, in a microstructure from the surface to a 1/16 position of the sheet thickness in the sheet thickness direction from the surface, a pole density in a (110)<1-11> orientation is 3.0 or less.Type: ApplicationFiled: December 8, 2020Publication date: November 24, 2022Applicant: NIPPON STEEL CORPORATIONInventors: Daisuke ITO, Shohei YABU, Takeshi TOYODA
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Publication number: 20220259692Abstract: This hot-rolled steel sheet has a predetermined chemical composition, in which a microstructure contains, by area %, bainite: 80.0% or more, ferrite: 10.0% or less, and a remainder in the microstructure: 10.0% or less, a total density of a length L7 of a grain boundary having a crystal orientation difference of 7° and a length L68 of a grain boundary having a crystal orientation difference of 68° about a <110> direction in the bainite is 0.35 to 0.60 ?m/?m2, and a tensile strength is 780 MPa or more.Type: ApplicationFiled: October 12, 2020Publication date: August 18, 2022Applicant: NIPPON STEEL CORPORATIONInventors: Shohei YABU, Kunio HAYASHI, Koutarou HAYASHI, Kazumasa TSUTSUI
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Patent number: 11365465Abstract: A steel sheet includes a predetermined chemical composition, and includes a steel microstructure represented by, in an area ratio, ferrite: 5% to 80%, a hard microstructure constituted of bainite, martensite or retained austenite or an arbitrary combination of the above: 20% to 95%, and a standard deviation of a line fraction of the hard microstructure on a line in a plane perpendicular to a thickness direction: 0.050 or less in a depth range where a depth from a surface when a thickness of a steel sheet is set as t is from 3t/8 to t/2.Type: GrantFiled: August 8, 2017Date of Patent: June 21, 2022Assignee: NIPPON STEEL CORPORATIONInventors: Shohei Yabu, Akihiro Uenishi, Koutarou Hayashi
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Publication number: 20220145415Abstract: The present invention relates to a cold rolled steel sheet containing C: 0.15% or more and 0.40% or less, Si: 0.50% or more and 4.00% or less, Mn: 1.00% or more and 4.00% or less, and sol. Al: 0.001% or more and 2.000% or less, having a metallic structure consisting of 35 to 65 area % of ferrite phases, 35 to 65 area % of hard second phases, and 0 to 5 area % of remaining phases, wherein 60% or more of the ferrite phases are recrystallized ferrite phases, an average crystal grain size defined by 15° grain boundaries is 5.0 ?m or less, a maximum connecting rate of the hard second phases is 10% or more, and a two-dimensional isoperimetric constant of the hard second phases is 0.20 or less.Type: ApplicationFiled: March 31, 2020Publication date: May 12, 2022Applicant: NIPPON STEEL CORPORATIONInventors: Shohei YABU, Koutarou HAYASHI, Akihiro UENISHI
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Publication number: 20220090228Abstract: A hot-rolled steel sheet according to the present invention includes, as a chemical composition, by mass %: C: 0.030% to 0.250%; Si: 0.05% to 2.50%; Mn: 1.00% to 4.00%; Sol. Al: 0.001% to 2.000%; P: 0.100% or less; S: 0.0200% or less; N: 0.01000% or less; Ti: 0% to 0.20%; Nb: 0% to 0.20; B: 0% to 0.010%; V: 0% to 1.0%; Cr: 0% to 1.0%; Mo: 0% to 1.0%; Cu: 0% to 1.0%; Co: 0% to 1.0%; W: 0% to 1.0%; Ni: 0% to 1.0%; Ca: 0% to 0.01%; Mg: 0% to 0.01%; REM: 0% to 0.01%; Zr: 0% to 0.01%; and a remainder consisting of Fe and impurities, in which an area ratio of a scale damage portion, which is a portion lower than an average height of a surface of the steel sheet by 10 ?m or more, is 20% or less, and a tensile strength of the hot-rolled steel sheet is 780 MPa or more.Type: ApplicationFiled: March 5, 2020Publication date: March 24, 2022Applicant: NIPPON STEEL CORPORATIONInventors: Genki ABUKAWA, Hiroshi SHUTO, Kenta MORISAWA, Shohei YABU
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Publication number: 20210404040Abstract: A hot-rolled steel sheet includes, as chemical composition, C, Si, Mn, and sol.Al. In the hot-rolled steel sheet, a sum of an average of pole densities in a crystal orientation group consisting of {211}<111> to {111}<112> and a pole density in a crystal orientation of {110}<001> is 0.5 to 6.0 in the surface region, and the tensile strength is 780 to 1370 MPa.Type: ApplicationFiled: November 20, 2019Publication date: December 30, 2021Applicant: NIPPON STEEL CORPORATIONInventors: Genki ABUKAWA, Shohei YABU
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Publication number: 20210002741Abstract: A steel sheet including, in mass %, C: 0.05% or more and 0.30% or less, Si: 0.05% or more and 6.00% or less, Mn: 1.50% or more and 10.00% or less, and the balance: Fe and impurities, a steel sheet structure is composed of, in area ratio, 15% or more and 80% or less of ferrite and 20% or more and 85% or less in total of a hard structure composed of any one of bainite, martensite, or retained austenite, or any combination thereof, and to a steel sheet thickness t, an area ratio of a maximum coupled ferrite region in a region from a t/2 position at the steel sheet thickness center to a position at a depth of 3t/8 from a surface is 80% or more in area ratio to a total ferrite area, and a two-dimensional isoperimetric constant of the maximum coupled ferrite region is 0.35 or less.Type: ApplicationFiled: March 30, 2018Publication date: January 7, 2021Applicant: NIPPON STEEL CORPORATIONInventors: Shohei YABU, Koutarou HAYASHI, Akihiro UENISHI
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Publication number: 20200071801Abstract: A high strength steel sheet containing a large amount of Mn which has bendability suitable as a material for auto part use and a method of producing the same are provided. A high strength steel sheet comprising a center part in a sheet thickness and a softened surface layer part on one surface or both surfaces of the center part in the sheet thickness, characterized in that, the center part in the sheet thickness has an average Mn concentration of greater than 4.0 mass % and less than 10.0 mass %, each softened surface layer part has a thickness of 0.1% to 30% of the sheet thickness, and the softened surface layer part has an average Mn concentration of 2.5 mass % or less, a recrystallization rate of 90% or more, and recrystallized structures with an average crystal grain size of 0.1 ?m or more and 40 ?m or less.Type: ApplicationFiled: April 27, 2018Publication date: March 5, 2020Applicant: NIPPON STEEL CORPORATIONInventors: Shohei YABU, Koutarou HAYASHI, Genki ABUKAWA, Akihiro UENISHI
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Publication number: 20190144966Abstract: A steel sheet includes a predetermined chemical composition, and includes a steel microstructure represented by, in an area ratio, ferrite: 5% to 80%, a hard microstructure constituted of bainite, martensite or retained austenite or an arbitrary combination of the above: 20% to 95%, and a standard deviation of a line fraction of the hard microstructure on a line in a plane perpendicular to a thickness direction: 0.050 or less in a depth range where a depth from a surface when a thickness of a steel sheet is set as t is from 3t/8 to t/2.Type: ApplicationFiled: August 8, 2017Publication date: May 16, 2019Applicant: NIPPON STEEL & SUMITOMO METAL CORPORATIONInventors: Shohei YABU, Akihiro UENISHI, Koutarou HAYASHI