Patents by Inventor Noriaki Moriyasu
Noriaki Moriyasu 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: 20230140191Abstract: After low-temperature finish rolling has been performed on a steel material having a certain chemical composition, cooling is performed at an average cooling rate of 10° C./s or higher to a temperature of 500° C., rapid cooling is further performed in a temperature range from a Ms temperature to a temperature of (Ms temperature - 200° C.), coiling is thereafter performed in a low temperature range of 250° C. or lower, and the coiled steel sheet is uncoiled and further subjected to rolling with a certain amount or more of rolling load per unit width and the like. Consequently, it is possible to obtain a high-strength hot-rolled steel sheet having a microstructure including, in terms of area fraction, 95% or more of a martensite phase at a position located at ¼ of the thickness of the steel sheet, in which an average aspect ratio of prior austenite grains is 3.0 or more.Type: ApplicationFiled: March 17, 2021Publication date: May 4, 2023Applicant: JFE Steel CorporationInventors: Hiroshi Hasegawa, Hideyuki Kimura, Noriaki Moriyasu, Sota Goto
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Publication number: 20230120827Abstract: Provided is a high strength steel sheet that has a tensile strength of 1180 MPa or more and a uniform elongation of 6 % or more. The high strength steel sheet has a chemical composition that contains predetermined components with a MSC of 3.0 mass% to 4.2 mass%. The high strength steel sheet has a microstructure including upper bainite in an area fraction of 70 % or more as a main phase, fresh martensite and retained austenite in a total area fraction of 7 % to 30 %, with the retained austenite having an area fraction of 2 % or more. The high strength steel sheet has a mechanical property with a uniform elongation of 6 % or more and a tensile strength of 1180 MPa or more.Type: ApplicationFiled: March 11, 2021Publication date: April 20, 2023Applicant: JFE STEEL CORPORATIONInventors: Thihuyen DOAN, Sota GOTO, Hiroshi HASEGAWA, Noriaki MORIYASU, Takanori UMINO, Takeshi UEDA
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Patent number: 11603571Abstract: There are provided a high-strength hot-rolled steel sheet having a tensile strength of 980 MPa or more and a production method therefor. The high-strength hot-rolled steel sheet has a predetermined component composition and a microstructure containing 75.0% or more by area and less than 97.0% by area of a primary phase composed of an upper bainite phase, the primary phase having an average grain size of 12.0 ?m or less, and more than 3.0% by area and 25.0% or less by area of a secondary phase that is a structure composed of one or two of a lower bainite phase and/or a tempered martensite phase, and a martensite phase, in which the number density of grains of the secondary phase having an equivalent circular diameter of 0.5 ?m or more is 150,000 grains/mm2 or less, and the steel sheet has an arithmetic mean surface roughness of 2.00 ?m or less.Type: GrantFiled: February 6, 2018Date of Patent: March 14, 2023Assignee: JFE STEEL CORPORATIONInventors: Kazuhiko Yamazaki, Shunsuke Toyoda, Noriaki Moriyasu, Sumio Kaiho
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Patent number: 11578375Abstract: A high-strength hot-rolled steel sheet that has excellent punching workability and hole expandability, and a method for manufacturing the same. The hot-rolled steel sheet has a tensile strength of 980 MPa or more. The hot-rolled steel sheet has a chemical composition containing C, Si, Mn, P, S, Al, N, Ti, Cr, and B, and has a microstructure including a bainite phase having an area ratio of 85% or more as a main phase, and a martensite phase or martensite-austenite constituent having an area ratio of 15% or less as a second phase, the balance being a ferrite phase. The second phase has an average grain diameter of 3.0 ?m or less, prior-austenite grains have an average aspect ratio of 1.3 or more and 5.0 or less, and recrystallized prior-austenite grains have an area ratio of 15% or less relative to non-recrystallized prior-austenite grains.Type: GrantFiled: July 20, 2016Date of Patent: February 14, 2023Assignee: JFE STEEL CORPORATIONInventors: Kazuhiko Yamazaki, Shunsuke Toyoda, Noriaki Moriyasu, Kentaro Irisa
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Patent number: 11208712Abstract: There is provided a galvanized steel sheet more highly excellent in terms of punchability. The steel sheet has a specified chemical composition and a microstructure including a ferrite phase and a tempered bainite phase in a total amount of 95% or more in terms of area ratio, in which the average grain diameter of the microstructure is 5.0 ?m or less, the amount of Fe precipitated is 0.10 mass % or more, the amount of Ti, Nb, and V precipitated in the form of precipitates having a grain diameter of less than 20 nm is 0.025 mass % or more in terms of precipitate C equivalent, and half or more of precipitates having a grain diameter of less than 20 nm are formed at random.Type: GrantFiled: February 1, 2018Date of Patent: December 28, 2021Assignee: JFE STEEL CORPORATIONInventors: Taro Kizu, Noriaki Moriyasu, Shigeyuki Nabeshima, Kazunori Tahara, Kana Sasaki
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Publication number: 20210140007Abstract: Provided is a high-strength hot rolled steel sheet that has excellent stretch flange formability, bendability, and low-temperature toughness while maintaining high strength of a tensile strength TS of 1180 MPa or more, and a method for manufacturing the high-strength hot rolled steel sheet. The high-strength hot rolled steel sheet includes a specific chemical composition, and a steel structure in which a lower bainite phase and/or a tempered martensite phase at 90% or more in terms of a total area fraction is contained as a dominant phase, an average grain size of the dominant phase is 10.0 ?m or less, and an amount of Fe in Fe-based precipitates is 0.70% or less in mass %, in which an arithmetic average roughness (Ra) of a surface is 2.50 ?m or less, and a tensile strength TS is 1180 MPa or more.Type: ApplicationFiled: June 10, 2019Publication date: May 13, 2021Applicant: JFE Steel CorporationInventors: Kazuhiko Yamazaki, Takeshi Yokota, Sumio Kaiho, Noriaki Moriyasu
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Publication number: 20210017636Abstract: There is provided a galvanized steel sheet more highly excellent in terms of punchability. The steel sheet has a specified chemical composition and a microstructure including a ferrite phase and a tempered bainite phase in a total amount of 95% or more in terms of area ratio, in which the average grain diameter of the microstructure is 5.0 ?m or less, the amount of Fe precipitated is 0.10 mass % or more, the amount of Ti, Nb, and V precipitated in the form of precipitates having a grain diameter of less than 20 nm is 0.025 mass % or more in terms of precipitate C equivalent, and half or more of precipitates having a grain diameter of less than 20 nm are formed at random.Type: ApplicationFiled: February 1, 2018Publication date: January 21, 2021Applicant: JFE STEEL CORPORATIONInventors: Taro KIZU, Noriaki MORIYASU, Shigeyuki NABESHIMA, Kazunori TAHARA, Kana SASAKI
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Publication number: 20200063227Abstract: There are provided a high-strength hot-rolled steel sheet having a tensile strength of 980 MPa or more and a production method therefor. The high-strength hot-rolled steel sheet has a predetermined component composition and a microstructure containing 75.0% or more by area and less than 97.0% by area of a primary phase composed of an upper bainite phase, the primary phase having an average grain size of 12.0 ?m or less, and more than 3.0% by area and 25.0% or less by area of a secondary phase that is a structure composed of one or two of a lower bainite phase and/or a tempered martensite phase, and a martensite phase, in which the number density of grains of the secondary phase having an equivalent circular diameter of 0.5 ?m or more is 150,000 grains/mm2 or less, and the steel sheet has an arithmetic mean surface roughness of 2.00 ?m or less.Type: ApplicationFiled: February 6, 2018Publication date: February 27, 2020Applicant: JFE Steel CorporationInventors: Kazuhiko Yamazaki, Shunsuke Toyoda, Noriaki Moriyasu, Sumio Kaiho
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Publication number: 20180237874Abstract: A high-strength hot-rolled steel sheet that has excellent punching workability and hole expandability, and a method for manufacturing the same. The hot-rolled steel sheet has a tensile strength of 980 MPa or more. The hot-rolled steel sheet has a chemical composition containing C, Si, Mn, P, S, Al, N, Ti, Cr, and B, and has a microstructure including a bainite phase having an area ratio of 85% or more as a main phase, and a martensite phase or martensite-austenite constituent having an area ratio of 15% or less as a second phase, the balance being a ferrite phase. The second phase has an average grain diameter of 3.0 ?m or less, prior-austenite grains have an average aspect ratio of 1.3 or more and 5.0 or less, and recrystallized prior-austenite grains have an area ratio of 15% or less relative to non-recrystallized prior-austenite grains.Type: ApplicationFiled: July 20, 2016Publication date: August 23, 2018Applicant: JFE STEEL CORPORATIONInventors: Kazuhiko YAMAZAKI, Shunsuke TOYODA, Noriaki MORIYASU, Kentaro IRISA
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Patent number: 9222155Abstract: A high strength hot-rolled steel sheet has a tensile strength of not less than 780 MPa and exhibits excellent stretch flangeability and excellent fatigue resistance. A steel has a composition containing C at 0.05 to 0.15%, Si at 0.2 to 1.2%, Mn at 1.0 to 2.0%, P at not more than 0.04%, S at not more than 0.005%, Ti at 0.05 to 0.15%, Al at 0.005 to 0.10% and N at not more than 0.007%.Type: GrantFiled: May 30, 2011Date of Patent: December 29, 2015Assignee: JFE Steel CorporationInventors: Nobuyuki Nakamura, Hayato Saito, Katsumi Nakajima, Yoshimasa Funakawa, Noriaki Moriyasu, Takayuki Murata
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Patent number: 9200344Abstract: A steel sheet including C at 0.05 to 0.15%, Si at 0.2 to 1.2%, Mn at 1.0 to 2.0%, P at not more than 0.04%, S at not more than 0.0030%, Al at 0.005 to 0.10%, N at not more than 0.005% and Ti at 0.03 to 0.13%, the balance being Fe and inevitable impurities, includes surface regions having an area fraction of bainite of less than 80% and an area fraction of a ferrite phase with a grain diameter of 2 to 15 ?m of not less than 10%, the surface regions extending from both surfaces of the steel sheet each to a depth of 1.5 to 3.0% relative to a total sheet thickness, as well as an inner region other than the surface regions having an area fraction of a bainite phase of more than 95%, and has a tensile strength of not less than 780 MPa.Type: GrantFiled: September 15, 2011Date of Patent: December 1, 2015Assignee: JFE Steel CorporationInventors: Hayato Saito, Katsumi Nakajima, Yoshimasa Funakawa, Noriaki Moriyasu, Takayuki Murata
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Publication number: 20140295210Abstract: A hot rolled steel sheet includes a composition including: C: 0.03% to less than 0.07%; Si: 0.3% or less; Mn: 0.5% to 2.0%; P: 0.025% or less; S: 0.005% or less; N: 0.0060% or less; Al: 0.1% or less; Ti: 0.07% to 0.11%; and V: 0.08% to less than 0.15% on a mass percent basis, such that Ti and V contents satisfy: 0.18?Ti+V?0.24 (where Ti and V are contents of the elements (by mass %)), the balance including Fe and inevitable impurities, a matrix having a ferrite phase with an area ratio of 95% or more; and a structure where fine carbide is dispersedly precipitated in the matrix, the fine carbide containing Ti and V has an average particle size of less than 10 nm, and a volume fraction of the fine carbide is 0.0020 or more, wherein the steel sheet has a tensile strength of 780 MPa or more.Type: ApplicationFiled: November 6, 2012Publication date: October 2, 2014Inventors: Tamako Ariga, Yoshimasa Funakawa, Noriaki Moriyasu
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Patent number: 8696832Abstract: A high-strength hot-rolled steel sheet has a tensile strength (TS) of 540 to 780 MPa, only small variations in strength, and excellent uniformity in strength using a general-purpose Ti-containing steel sheet, which is inexpensive. The high-strength hot-rolled steel sheet includes, on a mass percent basis, 0.05%-0.12% C, 0.5% or less Si, 0.8%-1.8% Mn, 0.030% or less P, 0.01% or less S, 0.005%-0.1% Al, 0.01% or less N, 0.030%-0.080% Ti, and the balance being Fe and incidental impurities. The microstructure have a bainitic ferrite fraction of 70% or more, and the amount of Ti present in a precipitate having a size of less than 20 nm is 50% or more of the value of Ti* calculated using formula (1): Ti*=[Ti]?48/14×[N] (1) where [Ti] and [N] represent a Ti content (percent by mass) and a N content (percent by mass), respectively, of the steel sheet.Type: GrantFiled: February 4, 2009Date of Patent: April 15, 2014Assignee: JFE Steel CorporationInventors: Shinjiro Kaneko, Kaneharu Okuda, Tetsuo Shimizu, Noriaki Moriyasu, Masahide Watabe
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Publication number: 20140007993Abstract: A high strength hot rolled steel sheet having excellent blanking workability is provided. The composition contains C: 0.050 to 0.15%, Si: 0.1 to 1.5%, Mn: 1.0 to 2.0%, P: 0.03% or less, S: 0.0030% or less, Al: 0.01 to 0.08%, Ti: 0.05 to 0.15%, N: 0.005% or less, and the balance being Fe and unavoidable impurities. More than 95% of the microstructure is formed of a bainite phase in terms of area fraction. Average grain diameters of the bainite phase in a region having a thickness equal to ¼ of the sheet thickness from the surface in the sheet thickness direction is 5 ?m or less in an L-direction cross section and 4 ?m or less in a C-direction cross section. The number of crystal grains extended in the rolling direction and having an aspect ratio of 5 or more is 7 or less in a sheet thickness center portion.Type: ApplicationFiled: September 15, 2011Publication date: January 9, 2014Applicant: JFE Steel CorporationInventors: Katsumi Nakajima, Hayato Saito, Yoshimasa Funakawa, Noriaki Moriyasu, Takayuki Murata
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Publication number: 20130276940Abstract: A steel having a composition that includes C: 0.05 to 0.15%, Si: 0.2 to 1.2%, Mn: 1.0 to 2.0%, Al: 0.005 to 0.10%, N: 0.006% or less, and at least one selected from Ti: 0.03 to 0.13%, Nb: 0.02 to 0.10%, and V: 0.02 to 0.15% is subjected to rough rolling at a reduction of 80% or more and finish rolling at a finish rolling delivery temperature in the range of 800 to 950° C. The finish rolled sheet is subjected to cooling including cooling the finish rolled sheet from the finish rolling delivery temperature to a cooling end temperature in the range of 550 to 610° C. at an average cooling rate of 25° C./sec. or more and cooling the finish rolled sheet from the cooling end temperature of the previous process to a coiling temperature at an average cooling rate of 100° C./sec. or more.Type: ApplicationFiled: September 15, 2011Publication date: October 24, 2013Applicant: JFE Steel CorporationInventors: Katsumi Nakajima, Hayato Saito, Yoshimasa Funakawa, Noriaki Moriyasu, Takayuki Murata
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Publication number: 20130206289Abstract: A high-strength hot-rolled steel sheet having excellent formability has a composition containing, by mass, 0.04% to 0.1% of C, 0.3% to 1.3% of Si, 0.8% to 1.8% of Mn, 0.03% or less of P, 0.005% or less of S, 0.005% or less of N, 0.005% to 0.1% of Al, and at least one element selected from 0.002% to less than 0.03% of Ti, 0.002% to less than 0.03% of V, and 0.002% to less than 0.02% of Nb, the balance being Fe and incidental impurities. The steel sheet has a microstructure in which the area fraction of ferrite phase in the entire structure is 85% or more, the area fraction of bainite phase in the entire structure is 10% or less, the area fraction of phases other than the ferrite and bainite phases in the entire structure is 5% or less, and the area fraction of acicular ferrite phase in the entire ferrite phase is 30% to less than 80%.Type: ApplicationFiled: August 9, 2011Publication date: August 15, 2013Applicant: JFE STEEL CORPORATIONInventors: Katsumi Nakajima, Tetsuya Mega, Reiko Mizuno, Noriaki Moriyasu
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Publication number: 20130167985Abstract: A steel sheet including C at 0.05 to 0.15%, Si at 0.2 to 1.2%, Mn at 1.0 to 2.0%, P at not more than 0.04%, S at not more than 0.0030%, Al at 0.005 to 0.10%, N at not more than 0.005% and Ti at 0.03 to 0.13%, the balance being Fe and inevitable impurities, includes surface regions having an area fraction of bainite of less than 80% and an area fraction of a ferrite phase with a grain diameter of 2 to 15 ?m of not less than 10%, the surface regions extending from both surfaces of the steel sheet each to a depth of 1.5 to 3.0% relative to a total sheet thickness, as well as an inner region other than the surface regions having an area fraction of a bainite phase of more than 95%, and has a tensile strength of not less than 780 MPa.Type: ApplicationFiled: September 15, 2011Publication date: July 4, 2013Applicant: JFE Steel CorporationInventors: Hayato Saito, Katsumi Nakajima, Yoshimasa Funakawa, Noriaki Moriyasu, Takayuki Murata
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Publication number: 20130160904Abstract: The steel sheet includes C: 0.04 to 0.12%, Si: 0.5 to 1.2%, Mn: 1.0 to 1.8%, P: not more than 0.03%, S: not more than 0.0030%, Al: 0.005 to 0.20%, N: not more than 0.005% and Ti: 0.03 to 0.13%, the balance being Fe and inevitable impurities, includes a microstructure containing a bainite phase at an area fraction exceeding 95% and having an average grain diameter of not more than 3 ?m, has a difference ?Hv1 of not more than 50 between a Vickers hardness value at 50 ?m from the surface and a Vickers hardness value at ¼ of a sheet thickness, has a difference ?Hv2 of not more than 40 between the Vickers hardness value at ¼ of the sheet thickness and a Vickers hardness value at ½ of the sheet thickness.Type: ApplicationFiled: September 15, 2011Publication date: June 27, 2013Inventors: Hayato Saito, Katsumi Nakajima, Yoshimasa Funakawa, Noriaki Moriyasu, Takayuki Murata
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Publication number: 20130087254Abstract: A high strength hot-rolled steel sheet has a composition containing more than 0.035% to 0.055% C, 0.2% or less Si, 0.35% or less Mn, 0.03% or less P, 0.03% or less S, 0.1% or less Al, 0.01% or less N, 0.08% to 0.25% Ti, and 0.0005% to 0.0035% B on a mass basis, solute B being 0.0005% or more, the remainder being Fe and unavoidable impurities; a matrix containing a ferrite phase having an area fraction of more than 95%; a microstructure in which Ti carbides having an average grain size of less than 10 nm are finely precipitated in grains of the ferrite phase and the volume fraction of the Ti carbides is 0.0015 to 0.007; and a tensile strength of 780 MPa or more.Type: ApplicationFiled: June 23, 2011Publication date: April 11, 2013Applicant: JFE STEEL CORPORATIONInventors: Yoshimasa Funakawa, Tamako Ariga, Noriaki Moriyasu, Takayuki Murata
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Publication number: 20130087252Abstract: A high-strength hot-rolled steel sheet has a composition including C: 0.005% or more and 0.050% or less, Si: 0.2% or less, Mn: 0.8% or less, P: 0.025% or less, S: 0.01% or less, N: 0.01% or less, Al: 0.06% or less, and Ti: 0.05% or more and 0.10% or less, on a mass percent basis, such that S, N, and Ti satisfy Ti?0.04+(N/14×48+S/32×48), the remainder being Fe and incidental impurities; a matrix in which a ferrite phase constitutes 95% by area or more of the entire structure; and a structure in which Ti-containing fine carbide having an average grain size of less than 10 nm is dispersedly precipitated, and the volume ratio of the fine carbide to the entire structure is 0.0007 or more.Type: ApplicationFiled: June 24, 2011Publication date: April 11, 2013Applicant: JFE STEEL CORPORATIONInventors: Tamako Ariga, Katsumi Nakajima, Yoshimasa Funakawa, Noriaki Moriyasu, Takayuki Murata