Patents by Inventor Tomoji Kumano
Tomoji Kumano 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: 11512360Abstract: A grain-oriented electrical steel sheet having a metallographic structure after secondary-recrystallized annealing including matrix grains of Goss-oriented secondary recrystallized grains, wherein an existence frequency of Goss-oriented crystal grains having a major diameter of 5 mm or less in the matrix grains is 1.5 grains/cm2 or more and 8 grains/cm2 or less, and the magnetic flux density B8 is 1.88 T or more, and wherein deviation angles from a rolling direction of [001] direction of the Goss-oriented crystal grains having the major diameter of 5 mm or less are 7? or less and 5° or less, in terms of a simple or arithmetic average of ? angle and ? angle, respectively, wherein the ? angle represents an angle formed by a longitudinal direction and a projection of the [001] on a specimen surface, and the ? angle represents a tilt of the [001] out of the specimen surface.Type: GrantFiled: June 21, 2019Date of Patent: November 29, 2022Assignee: NIPPON STEEL CORPORATIONInventors: Tomoji Kumano, Shinya Yano, Shingo Okada, Akio Oguri, Shota Morimoto
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Publication number: 20210262052Abstract: Provided is a grain-oriented electrical steel sheet, the core loss characteristics of which have been significantly improved without causing a deterioration in magnetic flux density. The grain-oriented electrical steel sheet: comprises 2.5-3.5% by mass of Si with the balance being Fe and inevitable impurities; has a sheet thickness of 0.18-0.35 mm; has a metallographic structure including matrix grains of Goss-oriented secondary recrystallized grains after secondary-recrystallized annealing, wherein Goss-oriented crystal grains existing in the matrix and having a major (long) diameter of 5 mm or smaller exist in the metallographic structure at a frequency of 1.5 grains/cm2 to 8 grains/cm2; and has a magnetic flux density B8 of 1.88T or greater.Type: ApplicationFiled: June 21, 2019Publication date: August 26, 2021Applicant: NIPPON STEEL CORPORATIONInventors: Tomoji KUMANO, Shinya YANO, Shingo OKADA, Akio OGURI, Shota MORIMOTO
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Patent number: 8303730Abstract: A slab with a predetermined composition is heated at 1280° C. to 1390° C. to make a substance functioning as an inhibitor to be solid-solved (step S1). Next, the slab is hot-rolled to obtain a steel strip (step S2). The steel strip is annealed to form a primary inhibitor in the steel strip (step S3). Next, the steel strip is cold-rolled once or more (step S4). Next, the steel strip is annealed to perform decarburization and to cause primary recrystallization (step S5). Next, nitriding treatment is performed on the steel strip in a mixed gas of hydrogen, nitrogen and ammonia under a state where the steel strip runs, to form a secondary inhibitor in the steel strip (step S6). Next, the steel strip is annealed to induce secondary recrystallization (step S7).Type: GrantFiled: September 8, 2009Date of Patent: November 6, 2012Assignee: Nippon Steel CorporationInventors: Tomoji Kumano, Yoshiyuki Ushigami, Shuichi Nakamura, Yohichi Zaizen
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Patent number: 8202374Abstract: A surface temperature of a slab is decreased down to 600° C. or lower between start of continuous casting (step S2) and start of slab reheating (step S3). The surface temperature of the slab is held at 150° C. or higher between the start of the continuous casting (step s2) and the start of the slab reheating (step S3). The surface temperature of the slab in the slab reheating (step S3) is set to not lower than 1080° C. and not higher than 1200° C.Type: GrantFiled: March 31, 2010Date of Patent: June 19, 2012Assignee: Nippon Steel CorporationInventors: Tomoji Kumano, Norihiro Yamamoto, Yoshiyuki Ushigami, Shuichi Nakamura
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Publication number: 20120037277Abstract: A surface temperature of a slab is decreased down to 600° C. or lower between start of continuous casting (step S2) and start of slab reheating (step S3). The surface temperature of the slab is held at 150° C. or higher between the start of the continuous casting (step s2) and the start of the slab reheating (step S3). The surface temperature of the slab in the slab reheating (step S3) is set to not lower than 1080° C. and not higher than 1200° C.Type: ApplicationFiled: March 31, 2010Publication date: February 16, 2012Inventors: Tomoji Kumano, Norihiro Yamamoto, Yoshiyuki Ushigami, Shuichi Nakamura
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Patent number: 7976645Abstract: In a production of grain-oriented electrical steel sheet that is heated at a temperature of not higher than 1350° C., (a) the hot-rolled sheet is heated to a prescribed temperature of 1000° C. to 1150° C., and after recrystallization is annealed for a required time at a lower temperature of 850° C. to 1100° C., or (b) in the hot-rolled sheet annealing process decarburization is conducted to adjust the difference in the amount of carbon before and after decarburization to 0.002 to 0.02 mass %. In the temperature elevation process used in the decarburization annealing of the steel sheet, heating is conducted in the temperature range of 550° C. to 720° C. at a heating rate of at least 40° C./s, preferably 75 to 125° C./s, utilizing induction heating for the rapid heating used in the temperature elevation process in decarburization annealing.Type: GrantFiled: May 23, 2007Date of Patent: July 12, 2011Assignee: Nippon Steel CorporationInventors: Yoshiyuki Ushigami, Norikazu Fujii, Tomoji Kumano
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Publication number: 20110155285Abstract: A slab with a predetermined composition is heated at 1280° C. to 1390° C. to make a substance functioning as an inhibitor to be solid-solved (step S1). Next, the slab is hot-rolled to obtain a steel strip (step S2). The steel strip is annealed to form a primary inhibitor in the steel strip (step S3). Next, the steel strip is cold-rolled once or more (step S4). Next, the steel strip is annealed to perform decarburization and to cause primary recrystallization (step S5). Next, nitriding treatment is performed on the steel strip in a mixed gas of hydrogen, nitrogen and ammonia under a state where the steel strip runs, to form a secondary inhibitor in the steel strip (step S6). Next, the steel strip is annealed to induce secondary recrystallization (step S7).Type: ApplicationFiled: September 8, 2009Publication date: June 30, 2011Inventors: Tomoji Kumano, Yoshiyuki Ushigami, Shuichi Nakamura, Yohichi Zaizen
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Patent number: 7857915Abstract: Reheating a grain-oriented electrical steel sheet slab comprising predetermined components to 1280° C. or more and a solid solution temperature of inhibitor substances or more, hot rolling, annealing, and cold rolling it, decarburization annealing it, nitriding it in a strip running state, coating an annealing separator, and finish annealing it during which making a precipitation ratio of N as AlN after hot rolling 20% or less, making a mean grain size of primary recrystallization 7 ?m to less than 20 ?m, and making a nitrogen increase ?N in the nitridation within a range of Equation (1) and making nitrogen contents ?N1 and ?N2 (front and back, mass %) of a 20% thickness portion of one surface of the steel strip (sheet) within a range of Equation (2): 0.007?([N]?14/48×[Ti])??N?[solAl]×14/27?([N]?14/48×[Ti])+0.0025??Equation (1) |?N1??N2|/?N?0.35??Equation (2).Type: GrantFiled: May 19, 2006Date of Patent: December 28, 2010Assignee: Nippon Steel CorporationInventors: Tomoji Kumano, Kenichi Murakami, Yoshiyuki Ushigami
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Patent number: 7833360Abstract: The invention provides a method of producing a grain-oriented electrical steel sheet of the complete solid solution nitrided type that is good in glass film formation and excellent in magnetic properties, which method comprises: C: 0.025 to 0.09%, hot-rolling the steel slab containing Si: 2.5 to 4.0% and acid-soluble Al into a hot-rolled steel strip; controlling the rate at which N contained in the hot-rolled steel strip is precipitated as AlN to a precipitation rate of 20% or less; conducting hot-rolled strip annealing and cold rolling conducting decarburization-annealing combined with primary recrystallization by during the former part of the process in an atmosphere whose PH2O/PH2 is 0.30 to 0.70 and then during the latter part thereof in an atmosphere whose PH2O/PH2 is 0.Type: GrantFiled: January 12, 2007Date of Patent: November 16, 2010Assignees: Nippon Steel Corporation, Nittetsu Plant Designing CorporationInventors: Tomoji Kumano, Shyuichi Yamazaki, Osamu Tanaka
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Publication number: 20090126832Abstract: In a production of grain-oriented electrical steel sheet that is heated at a temperature of not higher than 1350° C., (a) the hot-rolled sheet is heated to a prescribed temperature of 1000° C. to 1150° C., and after recrystallization is annealed for a required time at a lower temperature of 850° C. to 1100° C., or (b) in the hot-rolled sheet annealing process decarburization is conducted to adjust the difference in the amount of carbon before and after decarburization to 0.002 to 0.02 mass %. In the temperature elevation process used in the decarburization annealing of the steel sheet, heating is conducted in the temperature range of 550° C. to 720° C. at a heating rate of at least 40° C./s, preferably 75 to 125° C./s, utilizing induction heating for the rapid heating used in the temperature elevation process in decarburization annealing.Type: ApplicationFiled: May 23, 2007Publication date: May 21, 2009Inventors: Yoshiyuki Ushigami, Norikazu Fujii, Tomoji Kumano
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Publication number: 20090044881Abstract: Reheating a grain-oriented electrical steel sheet slab comprising predetermined components to 1280° C. or more and a solid solution temperature of inhibitor substances or more, hot rolling, annealing, and cold rolling it, decarburization annealing it, nitriding it in a strip running state, coating an annealing separator, and finish annealing it during which making a precipitation ratio of N as AlN after hot rolling 20% or less, making a mean grain size of primary recrystallization 7 ?m to less than 20 ?m, and making a nitrogen increase ?N in the nitridation within a range of Equation (1) and making nitrogen contents ?N1 and ?N2 (front and back, mass %) of a 20% thickness portion of one surface of the steel strip (sheet) within a range of Equation (2): 0.007?([N]?14/48×[Ti])??N?[solAl]×14/27?([N]?14/48×[Ti])+0.0025??Equation (1) |?N1??N2|/?N?0.Type: ApplicationFiled: May 19, 2006Publication date: February 19, 2009Inventors: Tomoji Kumano, Kenichi Murakami, Yoshiyuki Ushigami
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Publication number: 20090032142Abstract: The invention provides a method of producing a grain-oriented electrical steel sheet of the complete solid solution nitrided type that is good in glass film formation and excellent in magnetic properties, which method comprises: C: 0.025 to 0.09%, hot-rolling the steel slab containing Si: 2.5 to 4.0% and acid-soluble Al into a hot-rolled steel strip; controlling the rate at which N contained in the hot-rolled steel strip is precipitated as AlN to a precipitation rate of 20% or less; conducting hot-rolled strip annealing and cold rolling conducting decarburization-annealing combined with primary recrystallization by during the former part of the process in an atmosphere whose PH2O/PH2 is 0.30 to 0.70 and then during the latter part thereof in an atmosphere whose PH2O/PH2 is 0.Type: ApplicationFiled: January 12, 2007Publication date: February 5, 2009Applicants: Nippon Steel Corporation, Nittetsu Plant Designing CorporationInventors: Tomoji Kumano, Shyuichi Yamazaki, Osamu Tanaka
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Patent number: 7471182Abstract: A means for treating the end faces of a core which is used for an electrical apparatuses and etc., to give insulation extremely superior in effect of improvement of the insulation, corrosion resistance, adhesiveness, heat resistance, and magnetic properties at a low temperature in a short time without cleaning for removing punching oil, annealing, or other pre-treatment; a core having an insulation coating comprised of a dry film of a pure silicone polymer, modified silicone polymer, and/or mixed silicone polymer as a silicone compound on the core end faces and having an average film thickness of at least 0.5 ?m, a breakdown voltage of at least 30V, and a heat resistance in the air of at least 400° C.; and a method of production comprised of forming a core, then dipping it in or spraying it by one or more types of a pure silicone polymer, modified silicone polymer, and/or mixed silicone polymer as an insulation coating.Type: GrantFiled: January 12, 2007Date of Patent: December 30, 2008Assignees: Nippon Steel Corporation, Nittetsu Plant Designing CorporationInventors: Tomoji Kumano, Chikara Kaido, Hiroyasu Fujii, Kazutaka Higashine, Osamu Tanaka, Norikazu Fujii, Kazufumi Hanzawa, Masayoshi Tanaka, Yuji Kubo, Noriko Yamada
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Publication number: 20070188289Abstract: A means for treating the end faces of a core which is used for an electrical apparatuses and etc., to give insulation extremely superior in effect of improvement of the insulation, corrosion resistance, adhesiveness, heat resistance, and magnetic properties at a low temperature in a short time without cleaning for removing punching oil, annealing, or other pre-treatment; a core having an insulation coating comprised of a dry film of a pure silicone polymer, modified silicone polymer, and/or mixed silicone polymer as a silicone compound on the core end faces and having an average film thickness of at least 0.5 ?m, a breakdown voltage of at least 30V, and a heat resistance in the air of at least 400° C.; and a method of production comprised of forming a core, then dipping it in or spraying it by one or more types of a pure silicone polymer, modified silicone polymer, and/or mixed silicone polymer as an insulation coating.Type: ApplicationFiled: January 12, 2007Publication date: August 16, 2007Applicants: Nippon Steel Corporation, Nittetsu Plant Designing CorporationInventors: Tomoji Kumano, Chikara Kaido, Hiroyasu Fujii, Kazutaka Higashine, Osamu Tanaka, Norikazu Fujii, Kazufumi Hanzawa, Masayoshi Tanaka, Yuji Kubo, Noriko Yamada
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Patent number: 7173509Abstract: A means for treating the end faces of a core which is used for an electrical apparatuses and etc., to give insulation extremely superior in effect of improvement of the insulation, corrosion resistance, adhesiveness, heat resistance, and magnetic properties at a low temperature in a short time without cleaning for removing punching oil, annealing, or other pre-treatment; a core having an insulation coating comprised of a dry film of a pure silicone polymer, modified silicone polymer, and/or mixed silicone polymer as a silicone compound on the core end faces and having an average film thickness of at least 0.5 ?m, a breakdown voltage of at least 30V, and a heat resistance in the air of at least 400° C.; and a method of production comprised of forming a core, then dipping it in or spraying it by one or more types of a pure silicone polymer, modified silicone polymer, and/or mixed silicone polymer as an insulation coating.Type: GrantFiled: October 4, 2002Date of Patent: February 6, 2007Assignees: Nippon Steel Corporation, Nittetsu Plant Designing CorporationInventors: Tomoji Kumano, Chikara Kaido, Hiroyasu Fujii, Kazutaka Higashine, Osamu Tanaka, Norikazu Fujii, Kazufumi Hanzawa, Masayoshi Tanaka, Yuji Kubo, Noriko Yamada
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Publication number: 20040046632Abstract: A means for treating the end faces of a core which is used for an electrical apparatuses and etc., to give insulation extremely superior in effect of improvement of the insulation, corrosion resistance, adhesiveness, heat resistance, and magnetic properties at a low temperature in a short time without cleaning for removing punching oil, annealing, or other pre-treatment; a core having an insulation coating comprised of a dry film of a pure silicone polymer, modified silicone polymer, and/or mixed silicone polymer as a silicone compound on the core end faces and having an average film thickness of at least 0.5 &mgr;m, a breakdown voltage of at least 30V, and a heat resistance in the air of at least 400° C.; and a method of production comprised of forming a core, then dipping it in or spraying it by one or more types of a pure silicone polymer, modified silicone polymer, and/or mixed silicone polymer as an insulation coating.Type: ApplicationFiled: June 4, 2003Publication date: March 11, 2004Inventors: Tomoji Kumano, Chikara Kaido, Hiroyasu Fujii, Kazutaka Higashine, Osamu Tanaka, Norikazu Fujii, Kazufumi Hanzawa, Masayoshi Tanaka, Yuji Kubo, Noriko Yamada
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Patent number: 6478892Abstract: The present invention provides a non-oriented electrical steel sheet having crystal grains of small diameter and excellent workability before stress relief annealing and having crystal grains of largely grown diameter and excellent iron loss property after stress relief annealing and a method for producing the same, and relates to a low iron loss non-oriented electrical steel sheet excellent in workability, containing, in weight %, 0.010% or less of C, 0.1 to 1.5% of Mn, 0.1 to 4% of Si, 0.1 to 4% of Al, wherein the latter three elements satisfy the formula Si+Mn+Al≦5.0%, and 0.0005 to 0.0200% of Mg, or further containing 0.005% or more of Ca, wherein the total amount of Mg and Ca is 0.0200% or less, or further containing 0.005% or more of REM, wherein the total amount of Mg and REM is 0.0200% or less, or further containing 0.005% or more of Ca and REM, wherein the total amount of Mg, Ca and REM is 0.0200% or less, and containing the remainder consisting of Fe and unavoidable impurities.Type: GrantFiled: April 6, 2001Date of Patent: November 12, 2002Assignee: Nippon Steel CorporationInventors: Ken-ichi Murakami, Takashi Morohoshi, Tomoji Kumano, Ryutaro Kawamata, Takeshi Kubota, Masafumi Zeze, Hidekuni Murakami, Shinichi Kanao
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Patent number: 6432222Abstract: A method for producing a grain-oriented electrical steel sheet excellent in magnetic property, comprising the steps of; heating a slab containing a prescribed amount of Al to a temperature of 1,200° C. or higher, hot-rolling the slab into a hot-rolled strip, annealing the strip as required, cold-rolling it once or twice or more with intermediate annealing(s), and decarburization annealing the cold rolled sheet, and final box annealing after the application of an annealing separator to prevent strip sticking during the annealing, characterized by heating the slab to a temperature (slab heating temperature Ts (° C.)) higher than the complete solution temperature of substances having intensities as inhibitors and nitriding treating the decarburization annealed steel sheet before the commencement of secondary recrystallization during the final box annealing.Type: GrantFiled: June 4, 2001Date of Patent: August 13, 2002Assignee: Nippon Steel CorporationInventors: Yoshifumi Ohata, Tomoji Kumano, Norikazu Fujii, Hisashi Mogi, Hitoshi Yokouchi, Norihiro Yamamoto
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Publication number: 20020007870Abstract: A method for producing a grain-oriented electrical steel sheet excellent in magnetic property, comprising the steps of; heating a slab containing a prescribed amount of Al to a temperature of 1,200° C. or higher, hot-rolling the slab into a hot-rolled strip, annealing the strip as required, cold-rolling it once or twice or more with intermediate annealing(s), and decarburization annealing the cold rolled sheet, and final box annealing after the application of an annealing separator to prevent strip sticking during the annealing, characterized by heating the slab to a temperature (slab heating temperature Ts(° C.)) higher than the complete solution temperature of substances having intensities as inhibitors and nitriding treating the decarburization annealed steel sheet before the commencement of secondary recrystallization during the final box annealing.Type: ApplicationFiled: June 4, 2001Publication date: January 24, 2002Inventors: Yoshifumi Ohata, Tomoji Kumano, Norikazu Fujii, Hisashi Mogi, Hitoshi Yokouchi, Norihiro Yamamoto
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Publication number: 20010037841Abstract: The present invention provides a non-oriented electrical steel sheet having crystal grains of small diameter and excellent workability before stress relief annealing and having crystal grains of largely grown diameter and excellent iron loss property after stress relief annealing and a method for producing the same, and relates to a low iron loss non-oriented electrical steel sheet excellent in workability, containing, in weight %, 0.010% or less of C, 0.1 to 1.5% of Mn, 0.1 to 4% of Si, 0.1 to 4% of Al, wherein the latter three elements satisfy the formula Si+Mn+Al≦5.0%, and 0.0005 to 0.0200% of Mg, or further containing 0.005% or more of Ca, wherein the total amount of Mg and Ca is 0.0200% or less, or further containing 0.005% or more of REM, wherein the total amount of Mg and REM is 0.0200% or less, or further containing 0.005% or more of Ca and REM, wherein the total amount of Mg, Ca and REM is 0.0200% or less, and containing the remainder consisting of Fe and unavoidable impurities.Type: ApplicationFiled: April 6, 2001Publication date: November 8, 2001Inventors: Ken-ichi Murakami, Takashi Morohoshi, Tomoji Kumano, Ryutaro Kawamata, Takeshi Kubota, Masafumi Zeze, Hidekuni Murakami, Shinichi Kanao