Patents by Inventor Yuiko Wakisaka
Yuiko Wakisaka 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: 10889880Abstract: Provided are a grain-oriented electrical steel sheet with low iron loss even when including at least one grain boundary segregation element among Sb, Sn, Mo, Cu, and P, and a method for manufacturing the same. In our method, Pr is controlled to satisfy Pr??0.075T+18, where T>10, 5<Pr, T (hr) is the time required after final annealing to reduce the temperature of a secondary recrystallized sheet from 800° C. to 400° C., and Pr (MPa) is the line tension on the secondary recrystallized sheet during flattening annealing. As a result, a grain-oriented electrical steel sheet in which iron loss is low and a dislocation density near crystal grain boundaries of the steel substrate is 1.0×1013 m?2 or less can be obtained even when the grain-oriented electrical steel sheet contains at least one of Sb, Sn, Mo, Cu, and P.Type: GrantFiled: March 4, 2016Date of Patent: January 12, 2021Assignee: JFE STEEL CORPORATIONInventors: Takeshi Imamura, Masanori Takenaka, Yuiko Wakisaka
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Patent number: 10066286Abstract: Provided is an apparatus for continuously nitriding a strip continuously being fed after cold rolling and before secondary recrystallization annealing in a production line of a grain-oriented electrical steel sheet, comprising: a nitriding zone for nitriding the strip; a cooling zone for cooling the strip; and an optional heating zone provided upstream of the nitriding zone for heating the strip, wherein, the nitriding zone is provided with glow discharge electrodes, and by plasma nitriding the strip by glow discharge with the glow discharge electrodes functioning as positive electrodes and the strip functioning as a negative electrode, inhibitor forming elements are uniformly dispersed over the full length and full width of the strip and a grain-oriented electrical steel sheet with excellent magnetic properties with no variation is obtained.Type: GrantFiled: February 18, 2014Date of Patent: September 4, 2018Assignee: JFE STEEL CORPORATIONInventors: Hiroshi Matsuda, Hideyuki Takahashi, Hiroi Yamaguchi, Yasuyuki Hayakawa, Takashi Terashima, Yuiko Wakisaka
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Patent number: 9953752Abstract: A method for producing grain-oriented electrical steel sheets includes subjecting a steel slab to hot rolling to obtain a hot rolled sheet, the steel slab having a composition consisting of, by mass % or mass ppm, C: 0.08% or less, Si: 2.0% to 4.5% and Mn: 0.5% or less, S, Se, and O: less than 50 ppm each, sol.Al: less than 100 ppm, N: 80 ppm or less, and the balance being Fe and incidental impurities, and satisfying the relation of sol.Al (ppm)?N (ppm)×(26.98/14.00)?30 ppm; then subjecting the hot rolled sheet to annealing and rolling to obtain a cold rolled sheet; then subjecting the cold rolled sheet to nitriding treatment, under specific condition, before, during or after primary recrystallization annealing; then applying an annealing separator on the cold rolled sheet; and subjecting the cold rolled sheet to secondary recrystallization annealing.Type: GrantFiled: December 25, 2013Date of Patent: April 24, 2018Assignee: JFE STEEL CORPORATIONInventors: Yukihiro Shingaki, Hiroi Yamaguchi, Yuiko Wakisaka, Hiroshi Matsuda, Takashi Terashima
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Publication number: 20180066346Abstract: Provided are a grain-oriented electrical steel sheet with low iron loss even when including at least one grain boundary segregation element among Sb, Sn, Mo, Cu, and P, and a method for manufacturing the same. In our method, Pr is controlled to satisfy Pr??0.075T+18, where T>10, 5<Pr, T (hr) is the time required after final annealing to reduce the temperature of a secondary recrystallized sheet from 800° C. to 400° C., and Pr (MPa) is the line tension on the secondary recrystallized sheet during flattening annealing. As a result, a grain-oriented electrical steel sheet in which iron loss is low and a dislocation density near crystal grain boundaries of the steel substrate is 1.0×1013 m?2 or less can be obtained even when the grain-oriented electrical steel sheet contains at least one of Sb, Sn, Mo, Cu, and P.Type: ApplicationFiled: March 4, 2016Publication date: March 8, 2018Applicant: JFE STEEL CORPORATIONInventors: Takeshi IMAMURA, Masanori TAKENAKA, Yuiko WAKISAKA
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Patent number: 9905343Abstract: A method for producing a grain-oriented electrical steel sheets includes subjecting a steel slab to hot rolling to obtain a hot rolled sheet, the steel slab having a specific composition; then subjecting the hot rolled sheet to annealing and rolling to obtain a cold rolled sheet; then subjecting the cold rolled sheet to nitriding treatment with a nitrogen increase of 50 to 1000 ppm, during or after primary recrystallization annealing; then applying an annealing separator on the cold rolled sheet; and setting the staying time in a temperature range of 300 to 800° C. in the secondary recrystallization annealing to 5 to 150 hours.Type: GrantFiled: December 25, 2013Date of Patent: February 27, 2018Assignee: JFE STEEL CORPORATIONInventors: Yukihiro Shingaki, Yasuyuki Hayakawa, Hiroi Yamaguchi, Hiroshi Matsuda, Yuiko Wakisaka
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Patent number: 9748028Abstract: In a method for producing a grain-oriented electrical steel sheet by hot rolling a steel slab having a chemical composition including C: 0.001˜0.10 mass %, Si: 1.0˜5.0 mass %, Mn: 0.01˜0.5 mass %, Al: less than 0.0100 mass %, each of S, Se, O and N: not more than 0.0050 mass % and the remainder being Fe and inevitable impurities, subjecting the resulting hot rolled sheet to a single cold rolling or two or more cold rollings sandwiching an intermediate annealing therebetween to a final thickness, subjecting to a primary recrystallization annealing, applying an annealing separator thereto and then subjecting to a finish annealing, a zone of 550˜700° C. in a heating process of the primary recrystallization annealing is rapidly heated at an average heating rate of 40˜200° C./s, while any temperature zone of 250˜550° C. is kept at a heating rate of not more than 10° C.Type: GrantFiled: July 25, 2013Date of Patent: August 29, 2017Assignee: JFE STEEL CORPORATIONInventors: Yukihiro Shingaki, Takeshi Imamura, Ryuichi Suehiro, Yasuyuki Hayakawa, Yuiko Wakisaka
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Patent number: 9708682Abstract: Grain-oriented electrical steel sheets with good magnetic properties are industrially stably produced, by using as the material, a steel slab having a predetermined composition, wherein after cold rolling and before the start of secondary recrystallization annealing, the cold rolled sheet is subjected to nitriding treatment with nitrogen content of 50 mass ppm or more and 1000 mass ppm or less, and a total content of 0.2 mass % to 15 mass % of a sulfide and/or sulfate is contained in an annealing separator, and a staying time in the temperature range of 300° C. to 800° C. in the heating stage of secondary recrystallization annealing of 5 hours or more is secured to precipitate silicon nitride (Si3N4) and MnS, and using the silicon nitride in combination with MnS as inhibiting force for normal grain growth to significantly reduce variation of magnetic properties.Type: GrantFiled: December 25, 2013Date of Patent: July 18, 2017Assignee: JFE STEEL CORPORATIONInventors: Yasuyuki Hayakawa, Yukihiro Shingaki, Hiroi Yamaguchi, Hiroshi Matsuda, Yuiko Wakisaka
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Publication number: 20170121785Abstract: A primary recrystallization annealed sheet obtainable after an intermediate step of nitriding treatment in a grain-oriented electrical steel sheet production process using, as a material, a steel slab contains, in mass %, 0.001% to 0.10% of C, 1.0% to 5.0% of Si, 0.01% to 0.5% of Mn, 0.002% to 0.040% of one or two selected from S and Se, 0.001% to 0.050% of sol.Al, and 0.0010% to 0.020% of N, the remainder being Fe and incidental impurities. A nitrogen increase ?N due to the nitriding treatment is 1000 ppm or less, and N intensity according to X-ray fluorescence at the steel sheet surface is 0.59 or greater. As a result, uniform sheet thickness direction dispersion of nitrides as inhibitors can be achieved with industrial reliability in a grain-oriented electrical steel sheet production process including nitriding, thereby enabling reliable production of grain-oriented electrical steel sheets having good magnetic properties.Type: ApplicationFiled: March 26, 2015Publication date: May 4, 2017Inventors: Yukihiro Shingaki, Yuiko Wakisaka, Hirotaka Inoue
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Publication number: 20150361544Abstract: Provided is an apparatus for continuously nitriding a strip continuously being fed after cold rolling and before secondary recrystallization annealing in a production line of a grain-oriented electrical steel sheet, comprising: a nitriding zone for nitriding the strip; a cooling zone for cooling the strip; and an optional heating zone provided upstream of the nitriding zone for heating the strip, wherein, the nitriding zone is provided with glow discharge electrodes, and by plasma nitriding the strip by glow discharge with the glow discharge electrodes functioning as positive electrodes and the strip functioning as a negative electrode, inhibitor forming elements are uniformly dispersed over the full length and full width of the strip and a grain-oriented electrical steel sheet with excellent magnetic properties with no variation is obtained.Type: ApplicationFiled: February 18, 2014Publication date: December 17, 2015Applicant: JFE STEEL CORPORATIONInventors: Hiroshi MATSUDA, Hideyuki TAKAHASHI, Hiroi YAMAGUCHI, Yasuyuki HAYAKAWA, Takashi TERASHIMA, Yuiko WAKISAKA
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Publication number: 20150318094Abstract: A method for producing grain-oriented electrical steel sheets includes subjecting a steel slab to hot rolling to obtain a hot rolled sheet, the steel slab having a composition consisting of, by mass % or mass ppm, C: 0.08% or less, Si: 2.0% to 4.5% and Mn: 0.5% or less, S, Se, and O: less than 50 ppm each, sol.Al: less than 100 ppm, N: 80 ppm or less, and the balance being Fe and incidental impurities, and satisfying the relation of sol.Al (ppm)?N (ppm)×(26.98/14.00)?30 ppm; then subjecting the hot rolled sheet to annealing and rolling to obtain a cold rolled sheet; then subjecting the cold rolled sheet to nitriding treatment, under specific condition, before, during or after primary recrystallization annealing; then applying an annealing separator on the cold rolled sheet; and subjecting the cold rolled sheet to secondary recrystallization annealing.Type: ApplicationFiled: December 25, 2013Publication date: November 5, 2015Applicant: JFE STEEL CORPORATIONInventors: Yukihiro SHINGAKI, Hiroi YAMAGUCHI, Yuiko WAKISAKA, Hiroshi MATSUDA, Takashi TERASHIMA
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Publication number: 20150318092Abstract: A method for producing a grain-oriented electrical steel sheets includes subjecting a steel slab to hot rolling to obtain a hot rolled sheet, the steel slab having a specific composition; then subjecting the hot rolled sheet to annealing and rolling to obtain a cold rolled sheet; then subjecting the cold rolled sheet to nitriding treatment with a nitrogen increase of 50 to 1000 ppm, during or after primary recrystallization annealing; then applying an annealing separator on the cold rolled sheet; and setting the staying time in a temperature range of 300 to 800° C. in the secondary recrystallization annealing to 5 to 150 hours.Type: ApplicationFiled: December 25, 2013Publication date: November 5, 2015Applicant: JFE STEEL CORPORATIONInventors: Yukihiro SHINGAKI, Yasuyuki HAYAKAWA, Hiroi YAMAGUCHI, Hiroshi MATSUDA, Yuiko WAKISAKA
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Publication number: 20150299819Abstract: Grain-oriented electrical steel sheets with good magnetic properties are industrially stably produced, by using as the material, a steel slab having a predetermined composition, wherein after cold rolling and before the start of secondary recrystallization annealing, the cold rolled sheet is subjected to nitriding treatment with nitrogen content of 50 mass ppm or more and 1000 mass ppm or less, and a total content of 0.2 mass % to 15 mass % of a sulfide and/or sulfate is contained in an annealing separator, and a staying time in the temperature range of 300° C. to 800° C. in the heating stage of secondary recrystallization annealing of 5 hours or more is secured to precipitate silicon nitride (Si3N4) and MnS, and using the silicon nitride in combination with MnS as inhibiting force for normal grain growth to significantly reduce variation of magnetic properties.Type: ApplicationFiled: December 25, 2013Publication date: October 22, 2015Applicant: JFE STEEL CORPORATIONInventors: Yasuyuki HAYAKAWA, Yukihiro SHINGAKI, Hiroi YAMAGUCHI, Hiroshi MATSUDA, Yuiko WAKISAKA
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Publication number: 20150194247Abstract: In a method for producing a grain-oriented electrical steel sheet by hot rolling a steel slab having a chemical composition including C: 0.001˜0.10 mass %, Si: 1.0˜5.0 mass %, Mn: 0.01˜0.5 mass %, Al: less than 0.0100 mass %, each of S, Se, O and N: not more than 0.0050 mass % and the remainder being Fe and inevitable impurities, subjecting the resulting hot rolled sheet to a single cold rolling or two or more cold rollings sandwiching an intermediate annealing therebetween to a final thickness, subjecting to a primary recrystallization annealing, applying an annealing separator thereto and then subjecting to a finish annealing, a zone of 550˜700° C. in a heating process of the primary recrystallization annealing is rapidly heated at an average heating rate of 40˜200° C./s, while any temperature zone of 250˜550° C. is kept at a heating rate of not more than 10° C.Type: ApplicationFiled: July 25, 2013Publication date: July 9, 2015Inventors: Yukihiro Shingaki, Takeshi Imamura, Ryuichi Suehiro, Yasuyuki Hayakawa, Yuiko Wakisaka