Patents by Inventor Sota Goto
Sota Goto 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: 11732340Abstract: Provided is a high-strength hot-rolled coated steel sheet having a TS of 980 MPa or more, excellent bulging formability and stretch flange formability, and excellent coatability. The high-strength hot-rolled coated steel sheet includes a steel sheet having a chemical composition containing, by mass %, C: 0.03% to 0.09%, Si: 0.01% to 1.60%, Mn: 2.20% to 3.60%, P: 0.100% or less, S: 0.0100% or less, Ti: 0.05% to 0.18%, B: 0.0005% to 0.0050%, Al: 0.005% to 0.40%, N: 0.010% or less, and a balance of Fe and inevitable impurities, in which a CSM value expressed by the equation 33.8[% C][% Mn]+12.4[% Si]/[% Mn] is 3.3 to 12.0, and a steel microstructure containing bainite in an amount of 85% or more in terms of area fraction and martensite in an amount of 2.0% or more and 15.0% or less in terms of area fraction and includes a coating layer or an alloyed coating layer on a surface of the steel sheet.Type: GrantFiled: June 10, 2019Date of Patent: August 22, 2023Assignee: JFE STEEL CORPORATIONInventors: Sota Goto, Kazuhiko Yamazaki, Thi Huyen Doan, Yoshihiko Ono
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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: 11377719Abstract: A hot-rolled steel sheet for a heavy-wall, high-strength line pipe, the steel sheet having a chemical composition including, in mass %, C: 0.02 to 0.20%, Mn: 0.80 to 2.10%, Si: 0.01 to 0.50%, P: 0.034% or less, S: 0.0050% or less, Nb: 0.01 to 0.15%, Ti: 0.001 to 0.030%, and Al: 0.001 to 0.080%, the balance being Fe and incidental impurities, the steel sheet having a microstructure in which a main phase is a continuous cooling transformation structure and in which {001}? grains in a plane whose normal direction is the sheet width direction constitute an area fraction of 10% or less and have a combined size of 10 ?m or less, wherein the steel sheet has a tensile strength of 520 MPa or greater, and, in a drop weight tear test, a temperature at which a percent ductile fracture reaches 85% is ?25° C. or lower.Type: GrantFiled: June 6, 2017Date of Patent: July 5, 2022Assignee: JFE Steel CorporationInventors: Sota Goto, Hiroshi Nakata, Junji Shimamura
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Patent number: 11117348Abstract: Provided is a high-strength hot-rolled coated steel sheet with excellent formability, A high-strength hot-rolled coated steel sheet has a constituent composition containing, in a mass percent, C: 0.03% to 0.15%, Si: 0.4% or less, Mn: 1.2% to 1.9%, Ti: 0.05% to 0.25%, B: 0.0005% to 0.0050%, P: 0.03% or less, S: 0.005% or less, Al: 0.005% to 0.4%, and N: 0.01% or less, the balance being Fe and incidental impurities. The total area fraction of one or more of ferrite and tempered bainite is 90% or more. The steel sheet has a structure in which the volume fraction of Ti carbides having particle sizes of 20 nm or less is 0.05 vol % or more.Type: GrantFiled: February 26, 2018Date of Patent: September 14, 2021Assignee: JFE STEEL CORPORATIONInventors: Sota Goto, Kazuhiko Yamazaki, Taro Kizu, Shunsuke Toyoda
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Publication number: 20210238719Abstract: The high-strength hot-rolled coated steel sheet includes a steel sheet having a chemical composition containing, by mass %, C: 0.03% to 0.09%, Si: 0.01% to 1.60%, Mn: 2.20% to 3.60%, P: 0.100% or less, S: 0.0100% or less, Ti: 0.05% to 0.18%, B: 0.0005% to 0.0050%, Al: 0.005% to 0.40%, N: 0.010% or less, and a balance of Fe and inevitable impurities, in which a CSM value expressed by the equation 33.8[% C][% Mn]+12.4[% Si]/[% Mn] is 3.3 to 12.0, and a steel microstructure containing bainite in an amount of 85% or more in terms of area fraction and martensite in an amount of 2.0% or more and 15.0% or less in terms of area fraction and includes a coating layer or an alloyed coating layer on a surface of the steel sheet.Type: ApplicationFiled: June 10, 2019Publication date: August 5, 2021Applicant: JFE Steel CorporationInventors: Sota Goto, Kazuhiko Yamazaki, Thi Huyen Doan, Yoshihiko Ono
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Patent number: 11053564Abstract: A high-strength high-toughness electric-resistance-welded steel pipe having high resistance to post-weld heat treatment is provided. The steel pipe having a composition including C: 0.01% to 0.12%, Si: 0.05% to 0.50%, Mn: 1.0% to 2.2%, P: 0.03% or less, S: 0.005% or less, Al: 0.001% to 0.10%, N: 0.006% or less, Nb: 0.010% to 0.100%, and Ti: 0.001% to 0.050%. The steel pipe having a structure composed of a 90% or more by volume of a bainitic ferrite phase as a main phase and 10% or less (including 0%) by volume of a second phase. The bainitic ferrite phase having an average grain size of 10 ?m or less, and the structure containing fine Nb precipitates having a particle size of less than 20 nm dispersed in a base material portion. The steel pipe having high strength, toughness, and high resistance that is maintained through post-weld heat treatment.Type: GrantFiled: December 15, 2015Date of Patent: July 6, 2021Assignee: JFE STEEL CORPORATIONInventors: Sota Goto, Takatoshi Okabe, Yukihiko Okazaki
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Patent number: 11041223Abstract: A high-strength high-toughness electric-resistance-welded steel pipe having high resistance to post-weld heat treatment is provided. The steel pipe having a composition including C: 0.01% to 0.12%, Si: 0.05% to 0.50%, Mn: 1.0% to 2.2%, P: 0.03% or less, S: 0.005% or less, Al: 0.001% to 0.10%, N: 0.006% or less, Nb: 0.010% to 0.100%, and Ti: 0.001% to 0.050%. The steel pipe having a structure composed of 90% or more by volume of a bainitic ferrite phase and 10% or less (including 0%) by volume of a second phase. The bainitic ferrite phase having an average grain size of 10 ?m or less, and the structure containing fine Nb precipitates having a particle size of less than 20 nm dispersed in a base material portion. The steel pipe having high strength and toughness that is maintained through post-weld heat treatment, including heating to a temperature of 600° C. or more.Type: GrantFiled: December 15, 2015Date of Patent: June 22, 2021Assignee: JFE STEEL CORPORATIONInventors: Sota Goto, Takatoshi Okabe, Yukihiko Okazaki
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Publication number: 20210129491Abstract: Provided is a high-strength hot-rolled coated steel sheet with excellent formability, A high-strength hot-rolled coated steel sheet has a constituent composition containing, in a mass percent, C: 0.03% to 0.15%, Si: 0.4% or less, Mn: 1.2% to 1.9%, Ti: 0.05% to 0.25%, B: 0.0005% to 0.0050%, P: 0.03% or less, S: 0.005% or less, Al: 0.005% to 0.4%, and N: 0.01% or less, the balance being Fe and incidental impurities. The total area fraction of one or more of ferrite and tempered bainite is 90% or more. The steel sheet has a structure in which the volume fraction of Ti carbides having particle sizes of 20 nm or less is 0.05 vol % or more.Type: ApplicationFiled: February 26, 2018Publication date: May 6, 2021Applicant: JFE Steel CorporationInventors: Sota Goto, Kazuhiko Yamazaki, Taro Kizu, Shunsuke Toyoda
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Patent number: 10900104Abstract: A method for manufacturing a hot rolled steel sheet having a low yield ratio and that is excellent in low-temperature toughness, the steel sheet having a specified chemical composition. The method comprises hot rolling a steel material into a steel sheet, cooling the steel material using a cooling process comprising a first cooling and a second cooling, and performing a coiling process on the steel sheet in such a manner that the coiling temperature is 450° C. or more in terms of surface temperature of the steel sheet.Type: GrantFiled: July 5, 2018Date of Patent: January 26, 2021Assignee: JFE STEEL CORPORATIONInventors: Chikara Kami, Sota Goto
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Patent number: 10584405Abstract: A resistance welded steel pipe is provided. A hot-rolled steel sheet having a composition containing, in mass %, C: 0.025 to 0.168%, Si: 0.10 to 0.30%, Mn: 0.60 to 1.90%, and one or at least two selected from Ca, Nb, V, and Ti such that Pcm is 0.20 or less is subjected to continuous cold roll forming to obtain a pipe-shaped body. Tapered grooves are formed in the steel sheet such that the ratio of the tapered portions to the wall thickness of the steel sheet is 10 to 80%. Then end surfaces of the pipe-shaped body are butted against each other and subjected to electric resistance welding. Ultrasonic waves are transmitted toward the electric resistance weld surface such that a beam width is within the range of 0.1 to 4.0 mm, and the reflected waves are used for ultrasonic flaw detection using an ultrasonic flaw detector.Type: GrantFiled: November 17, 2015Date of Patent: March 10, 2020Assignee: JFE Steel CorporationInventors: Shunsuke Toyoda, Takatoshi Okabe, Sota Goto, Yutaka Matsui, Satoru Yabumoto
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Heavy wall electric resistance welded steel pipe for line pipe and method for manufacturing the same
Patent number: 10385417Abstract: By using, as a raw material, a thick hot-rolled steel sheet having a chemical composition containing, by mass %, C: 0.02% or more and 0.10% or less, Si: 0.05% or more and 0.30% or less, Mn: 0.80% or more and 2.00% or less, and Nb: 0.010% or more and 0.100% or less and satisfying the condition that a carbon equivalent Ceq is 0.25% or more and 0.50% or less, a microstructure including a bainitic ferrite phase and/or a bainite phase, a high strength of 52 ksi or more in terms of yield strength and a high toughness of ?45° C. or lower in terms of fracture transition temperature vTrs, and satisfying the condition that the ratio of the average crystal grain size of the coarsest-grain portion to the average crystal grain size of the finest-grain portion is 2.0 or less in every portion in the wall thickness direction is obtained.Type: GrantFiled: July 8, 2014Date of Patent: August 20, 2019Assignee: JFE Steel CorporationInventors: Sota Goto, Shunsuke Toyoda, Takatoshi Okabe -
Publication number: 20190211430Abstract: A hot-rolled steel sheet for a heavy-wall, high-strength line pipe, the steel sheet having a chemical composition including, in mass %, C: 0.02 to 0.20%, Mn: 0.80 to 2.10%, Si: 0.01 to 0.50%, P: 0.034% or less, S: 0.0050% or less, Nb: 0.01 to 0.15%, Ti: 0.001 to 0.030%, and Al: 0.001 to 0.080%, the balance being Fe and incidental impurities, the steel sheet having a microstructure in which a main phase is a continuous cooling transformation structure and in which {001}? grains in a plane whose normal direction is the sheet width direction constitute an area fraction of 10% or less and have a combined size of 10 ?m or less, wherein the steel sheet has a tensile strength of 520 MPa or greater, and, in a drop weight tear test, a temperature at which a percent ductile fracture reaches 85% is ?25° C. or lower.Type: ApplicationFiled: June 6, 2017Publication date: July 11, 2019Applicant: JFE Steel CorporationInventors: Sota Goto, Hiroshi Nakata, Junji Shimamura
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Patent number: 10287661Abstract: A hot-rolled steel sheet is provided having high strength and excellent toughness and ductility includes a composition that contains, on a mass percent basis, 0.04% or more and 0.15% or less of C, 0.01% or more and 0.55% or less of Si, 1.0% or more and 3.0% or less of Mn, 0.03% or less P, 0.01% or less S, 0.003% or more and 0.1% or less of Al, 0.006% or less N, 0.035% or more and 0.1% or less Nb, 0.001% or more and 0.1% or less of V, 0.001% or more and 0.1% or less Ti, and the balance being Fe and incidental impurities, in which the hot-rolled steel sheet includes a microstructure in which the proportion of precipitated Nb to the total amount of Nb is 35% or more and 80% or less, the volume fraction of tempered martensite and/or tempered bainite having a lath interval of 0.2 ?m or more and 1.6 ?m or less is 95% or more at a position 1.0 mm from a surface of the sheet in the thickness direction, and the volume fraction of ferrite having a lath interval of 0.2 ?m or more and 1.Type: GrantFiled: March 20, 2014Date of Patent: May 14, 2019Assignee: JFE STEEL CORPORATIONInventors: Tomoaki Shibata, Sota Goto
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Patent number: 10273554Abstract: A hot-rolled steel sheet has a chemical composition containing, by mass %, C: 0.030% or more and 0.120% or less, Si: 0.05% or more and 0.50% or less, Mn: 1.00% or more and 2.20% or less, P: 0.025% or less, S: 0.0050% or less, N: 0.0060% or less, Al: 0.005% or more and 0.100% or less, Nb: 0.020% or more and 0.100% or less, Mo: 0.05% or more and 0.50% or less, Ti: 0.001% or more and 0.100% or less, Cr: 0.05% or more and 0.50% or less, Ca: 0.0005% or more and 0.0050% or less, and the balance being Fe and inevitable impurities, and has a microstructure including bainitic ferrite as a main phase and martensite and retained austenite as second phases, wherein a volume fraction of the main phase is 90% or more, an average grain diameter of the main phase is 10 ?m or less, a volume fraction of the martensite is 0.5% or more and 9.5% or less, and a volume fraction of the retained austenite is 0.5% or more and 9.Type: GrantFiled: November 20, 2014Date of Patent: April 30, 2019Assignee: JFE Steel CorporationInventors: Tomoaki Shibata, Sota Goto
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Publication number: 20180312945Abstract: A method for manufacturing a hot rolled steel sheet having a low yield ratio and that is excellent in low-temperature toughness, the steel sheet having a specified chemical composition. The method comprises hot rolling a steel material into a steel sheet, cooling the steel material using a cooling process comprising a first cooling and a second cooling, and performing a coiling process on the steel sheet in such a manner that the coiling temperature is 450° C. or more in terms of surface temperature of the steel sheet.Type: ApplicationFiled: July 5, 2018Publication date: November 1, 2018Applicant: JFE STEEL CORPORATIONInventors: Chikara KAMI, Sota GOTO
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Publication number: 20180243809Abstract: Provided are an electric resistance welded stainless clad steel manufactured by forming a hot-rolled steel strip of clad steel including low-carbon low-alloy steel and stainless steel into a cylindrical shape, and electric resistance welding the edges of the hot-rolled steel strip, characterized in that the flattening characteristic of an electric resistance weld, as-welded, satisfies the formula h/D<0.3, wherein h is the flattened height at fracture (mm) and D is the outer diameter of the pipe (mm), and a method of manufacturing the same.Type: ApplicationFiled: February 18, 2016Publication date: August 30, 2018Applicant: JFE STEEL CORPORATIONInventors: Takatoshi Okabe, Sota Goto, Yuji Hashimoto, Yasushi Kato, Atsushi Matsumoto, Shinsuke Ide, Hiroki Ota
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Patent number: 10047416Abstract: A high strength hot rolled steel sheet is provided with low yield ratio and that is excellent in low-temperature toughness. The hot rolled steel sheet can be used as a raw material of a steel pipe. The steel sheet has a chemical composition containing C: 0.03% or more and 0.10% or less, Si: 0.01% or more and 0.50% or less, Mn: 1.4% or more and 2.2% or less, P: 0.025% or less, S: 0.005% or less, Al: 0.005% or more and 0.10% or less, Nb: 0.02% or more and 0.10% or less, Ti: 0.001% or more and 0.030% or less, Mo: 0.01% or more and 0.50% or less, Cr: 0.01% or more and 0.50% or less, and Ni: 0.01% or more and 0.50% or less, in which the condition that Moeq is 1.4% or more and 2.2% or less.Type: GrantFiled: September 11, 2013Date of Patent: August 14, 2018Assignee: JFE STEEL CORPORATIONInventors: Chikara Kami, Sota Goto
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Publication number: 20180030557Abstract: Provided is a high-strength electric resistance welded steel pipe having excellent bendability and which includes a composition containing, on a mass % basis, C: 0.04% to 0.15%, Si: 0.10% to 0.50%, Mn: 1.0% to 2.2%, P: 0.050% or less, S: 0.005% or less, Cr: 0.2% to 1.0%, Ti: 0.005% to 0.030%, and Al: 0.010% to 0.050%, the balance being Fe and unavoidable impurities, and a microstructure including polygonal ferrite with a volume fraction of 70% or more and retained austenite with a volume fraction of 3% to 20%, the balance being at least one selected from martensite, bainite, and pearlite, wherein the polygonal ferrite has an average grain size of 5 ?m or more and an aspect ratio of 1.40 or less.Type: ApplicationFiled: February 18, 2016Publication date: February 1, 2018Applicant: JFE STEEL CORPORATIONInventors: Sota Goto, Shunsuke Toyoda, Takatoshi Okabe
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Patent number: 9873164Abstract: Electric resistance welded steel pipes or steel tubes with a tensile property TS of not less than 434 MPa which have electric resistance welded parts exhibiting both excellent HIC resistance and excellent low-temperature toughness, and methods for manufacturing such steel pipes or steel tubes.Type: GrantFiled: September 20, 2013Date of Patent: January 23, 2018Assignee: JFE STEEL CORPORATIONInventors: Shunsuke Toyoda, Sota Goto, Takatoshi Okabe, Atsushi Yonemoto