Patents by Inventor Kengo Hata
Kengo Hata 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: 10774412Abstract: A hot-dip galvanized cold-rolled steel sheet has a tensile strength of 750 MPa or higher, a composition consisting, in mass percent, C: more than 0.10% and less than 0.25%, Si: more than 0.50% and less than 2.0%, Mn: more than 1.50% and 3.0% or less, and optionally containing one or more types of Ti, Nb, V, Cr, Mo, B, Ca, Mg, REM, and Bi, P: less than 0.050%, S: 0.010% or less, sol. Al: 0.50% or less, and N: 0.010% or less, and a main phase as a low-temperature transformation product and a second phase as retained austenite. The retained austenite volume fraction is more than 4.0% and less than 25.0% of the whole structure, and has an average grain size of less than 0.80 ?m. A number density of retained austenite grains having a grain size of 1.2 ?m or more is 3.0×10?2/?m2 or less.Type: GrantFiled: June 29, 2012Date of Patent: September 15, 2020Assignee: NIPPON STEEL CORPORATIONInventors: Norio Imai, Masayuki Wakita, Takuya Nishio, Jun Haga, Kengo Hata, Yasuaki Tanaka, Mitsuru Yoshida, Hiroshi Takebayashi, Suguhiro Fukushima, Toshiro Tomida
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Patent number: 10655200Abstract: The steel material according to the present invention contains, in mass %, C: 0.15 to 0.45%, Si: 0.10 to 1.0%, Mn: 0.10 to 0.8%, P: 0.050% or less, S: 0.010% or less, Al: 0.01 to 0.1%, N: 0.010% or less, Cr: 0.1 to 2.5%, Mo: 0.35 to 3.0%, Co: 0.05 to 2.0%, Ti: 0.003 to 0.040%, Nb: 0.003 to 0.050%, Cu: 0.01 to 0.50%, and Ni: 0.01 to 0.50%, and satisfies the following Formulae. A prior-austenite grain diameter of its microstructure is less than 5 ?m, and a block diameter of its microstructure is less than 2 ?m. The microstructure contains a total of 90% by volume or more of tempered martensite and tempered bainite. C+Mn/6+(Cr+Mo+V)/5+(Cu+Ni)/15?Co/6+??0.70??(1) (3C+Mo+3Co)/(3Mn+Cr)?1.0??(2).Type: GrantFiled: August 30, 2017Date of Patent: May 19, 2020Assignee: Nippon Steel CorporationInventors: Yuji Arai, Kengo Hata
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Patent number: 10526671Abstract: A high-strength cold-rolled steel sheet having excellent ductility and stretch flangeability includes: a chemical composition consisting, in mass %, C: 0.06 to 0.3, Si: 0.6 to 2.5%, Mn: 0.6 to 3.5%, P: at most 0.1%, S: at most 0.05%, Ti: 0 to 0.08%, Nb: 0 to 0.04%, total of Ti and Nb: 0 to 0.10%, sol.Al: 0 to 2.0%, Cr: 0 to 1%, Mo: 0 to 0.3%, V: 0 to 0.3%, B: 0 to 0.005%, Ca: 0 to 0.003%, REM: 0 to 0.003% and the remainder of Fe and impurities; a microstructure having a main phase including at least 40 area % in total of martensite and/or bainite; and a texture in which proportion of an average X-ray intensity in an {100}<011> to {211}<011> orientations relative to an average X-ray intensity of a random structure not having a texture is less than 6.Type: GrantFiled: February 13, 2013Date of Patent: January 7, 2020Assignee: NIPPON STEEL CORPORATIONInventors: Kengo Hata, Toshiro Tomida, Norio Imai, Jun Haga, Takuya Nishio
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Patent number: 10407749Abstract: A hot-rolled steel sheet having a composition comprising, in mass %, C: 0.06 to 0.3%, Si: 0.4 to 2.5%, Mn: 0.6 to 3.5%, P: at most 0.1%, S: at most 0.05%, Ti: 0 to 0.08%, Nb: 0 to 0.04%, a total content of Ti and Nb: 0 to 0.10%, sol.Al: 0 to 2.0%, Cr: 0 to 1%, Mo: 0 to 0.3%, V: 0 to 0.3%, B: 0 to 0.005%, Ca: 0 to 0.003%, REM: 0 to 0.003%, the remainder Fe and impurities, is cold rolled, then heated at an average heating rate of at least 15° C./sec so that a proportion of an unrecrystallization of a region not transformed to austenite at a time of reaching (Ac1 point+10° C.) is at least 30 area %, and then held for 30 seconds at temperature of at least (0.9×Ac1 point+0.1×Ac3 point) and at most (Ac3 point+100° C.).Type: GrantFiled: January 17, 2017Date of Patent: September 10, 2019Assignee: NIPPON STEEL CORPORATIONInventors: Kengo Hata, Toshiro Tomida, Norio Imai, Jun Haga, Takuya Nishio
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Publication number: 20190226063Abstract: The steel material according to the present invention contains, in mass %, C: 0.15 to 0.45%, Si: 0.10 to 1.0%, Mn: 0.10 to 0.8%, P: 0.050% or less, S: 0.010% or less, Al: 0.01 to 0.1%, N: 0.010% or less, Cr: 0.1 to 2.5%, Mo: 0.35 to 3.0%, Co: 0.05 to 2.0%, Ti: 0.003 to 0.040%, Nb: 0.003 to 0.050%, Cu: 0.01 to 0.50%, and Ni: 0.01 to 0.50%, and satisfies the following Formulae. A prior-austenite grain diameter of its microstructure is less than 5 ?m, and a block diameter of its microstructure is less than 2 ?m. The microstructure contains a total of 90% by volume or more of tempered martensite and tempered bainite. C+Mn/6+(Cr+Mo+V)/5+(Cu+Ni)/15?Co/6+??0.70??(1) (3C+Mo+3Co)/(3Mn+Cr)?1.Type: ApplicationFiled: August 30, 2017Publication date: July 25, 2019Inventors: Yuji Arai, Kengo Hata
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Patent number: 10174392Abstract: A method for producing a high-tensile cold-rolled steel sheet includes subjecting a slab having a composition containing C: more than 0.020% and less than 0.30%, Si: more than 0.10% and 3.00% or less, and Mn: more than 1.00% and 3.50% or less to hot rolling wherein the roll draft of the final one pass is higher than 15%, and rolling is finished in the temperature region of Ar3 point or higher, optionally annealing wherein the hot-rolled steel sheet is heated to 300° C. or higher after being cooled to 780° C. or lower, coiling higher than 400° C. or lower than 400° C., cold rolling the hot-rolled steel sheet or the annealed steel sheet, and annealing wherein the cold-rolled steel sheet is soaked in the temperature region of (Ac3 point?40° C.) or higher, cooling to 500° C. or lower and 300° C. or higher, and holding in that temperature region for 30 seconds or longer.Type: GrantFiled: July 2, 2012Date of Patent: January 8, 2019Assignee: NIPPON STEEL & SUMITOMO METAL CORPORATIONInventors: Jun Haga, Takuya Nishio, Masayuki Wakita, Yasuaki Tanaka, Norio Imai, Toshiro Tomida, Mitsuru Yoshida, Kengo Hata
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Publication number: 20170121788Abstract: A hot-rolled steel sheet having a composition comprising, in mass %, C: 0.06 to 0.3%, Si: 0.4 to 2.5%, Mn: 0.6 to 3.5%, P: at most 0.1%, S: at most 0.05%, Ti: 0 to 0.08%, Nb: 0 to 0.04%, a total content of Ti and Nb: 0 to 0.10%, sol.Al: 0 to 2.0%, Cr: 0 to 1%, Mo: 0 to 0.3%, V: 0 to 0.3%, B: 0 to 0.005%, Ca: 0 to 0.003%, REM: 0 to 0.003%, the remainder Fe and impurities, is cold rolled, then heated at an average heating rate of at least 15° C./sec so that a proportion of an unrecrystallization of a region not transformed to austenite at a time of reaching (Ac1 point+10° C.) is at least 30 area %, and then held for 30 seconds at temperature of at least (0.9×Ac1 point+0.1×Ac3 point) and at most (Ac3 point+100° C.).Type: ApplicationFiled: January 17, 2017Publication date: May 4, 2017Inventors: Kengo HATA, Toshiro TOMIDA, Norio IMAI, Jun HAGA, Takuya NISHIO
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Patent number: 9580767Abstract: A high-strength cold-rolled steel sheet includes a composition having controlled amounts of carbon, silicon, manganese, phosphorous, sulfur, titanium, niobium, sol. Aluminum, chromium, molybdenum, vanadium, boron, calcium, REM, and iron. A microstructure thereof has a main phase of ferrite of at least 40 area %, and a second phase of a low-temperature transformation phase consisting either or both of martensite and bainite, which comprises at least 10 area % in total and retained austenite (?) at least comprising 3 area % . An average grain diameter of ferrite has a tilt angle of at least 15° is at most 5.0 mm, an average grain diameter of the low-temperature transformation-produced phase is at most 2.0 mm, an average grain diameter of lump-like retained ? having an aspect ratio of less than 5 is at most 1.5 mm, and an area fraction of the lump-like retained ? relative to the retained ? is at least 50%.Type: GrantFiled: February 13, 2013Date of Patent: February 28, 2017Assignee: NIPPON STEEL & SUMITOMO METAL CORPORATIONInventors: Kengo Hata, Toshiro Tomida, Norio Imai, Jun Haga, Takuya Nishio
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Patent number: 9435013Abstract: A cold-rolled steel sheet having a refined structure in which grain growth during annealing is suppressed has a chemical composition containing, in mass percent, controlled amounts of carbon, manganese, niobium, titanium, vanadium, sol. Aluminum, chromium, molybdenum, boron, calcium, and REM and a microstructure which contains at least 50% by area of ferrite as a main phase, a second phase containing at least 10% by area of a low temperature transformation phase and 0-3% by area of retained austenite and which satisfies the following Equations (1)-(3), in addition to a particular texture, dm<2.7+10000/(5+300×C+50×Mn+4000×Nb+2000×Ti+400×V)2??(1), dm<4.0??(2), and ds?1.5??(3), wherein dm is the average grain diameter (?m) of ferrite defined by a high angle grain boundary having a tilt angle of at least 15°, and ds is the average grain diameter (?m) of the second phase.Type: GrantFiled: August 22, 2011Date of Patent: September 6, 2016Assignee: NIPPON STEEL & SUMITOMO METAL CORPORATIONInventors: Kengo Hata, Toshiro Tomida, Norio Imai
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Publication number: 20150037610Abstract: A high-strength cold-rolled steel sheet includes a composition having controlled amounts of carbon, silicon, manganese, phosphorous, sulfur, titanium, niobium, sol. Aluminum, chromium, molybdenum, vanadium, boron, calcium, REM, and iron. A microstructure thereof has a main phase of ferrite of at least 40 area %, and a second phase of a low-temperature transformation phase consisting either or both of martensite and bainite, which comprises at least 10 area % in total and retained austenite (?) at least comprising 3 area %. An average grain diameter of ferrite has a tilt angle of at least 15° is at most 5.0 mm, an average grain diameter of the low-temperature transformation-produced phase is at most 2.0 mm, an average grain diameter of lump-like retained ? having an aspect ratio of less than 5 is at most 1.5 mm, and an area fraction of the lump-like retained ? relative to the retained ? is at least 50%.Type: ApplicationFiled: February 13, 2013Publication date: February 5, 2015Inventors: Kengo Hata, Toshiro Tomida, Norio Imai, Jun Haga, Takuya Nishio
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Publication number: 20150027593Abstract: A high-strength cold-rolled steel sheet having excellent ductility and stretch flangeability includes: a chemical composition consisting, in mass %, C: 0.06 to 0.3, Si: 0.6 to 2.5%, Mn: 0.6 to 3.5%, P: at most 0.1%, S: at most 0.05%, Ti: 0 to 0.08%, Nb: 0 to 0.04%, total of Ti and Nb: 0 to 0.10%, sol.Al: 0 to 2.0%, Cr: 0 to 1%, Mo: 0 to 0.3%, V: 0 to 0.3%, B: 0 to 0.005%, Ca: 0 to 0.003%, REM: 0 to 0.003% and the remainder of Fe and impurities; a microstructure having a main phase including at least 40 area % in total of martensite and/or bainite; and a texture in which proportion of an average X-ray intensity in an {100}<011> to {211}<011> orientations relative to an average X-ray intensity of a random structure not having a texture is less than 6.Type: ApplicationFiled: February 13, 2013Publication date: January 29, 2015Inventors: Kengo Hata, Toshiro Tomida, Norio Ima, Jun Haga, Takuya Nishio
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Publication number: 20140238557Abstract: A method for producing a high-tensile cold-rolled steel sheet includes subjecting a slab having a composition containing C: more than 0.020% and less than 0.30%, Si: more than 0.10% and 3.00% or less, and Mn: more than 1.00% and 3.50% or less to hot rolling wherein the roll draft of the final one pass is higher than 15%, and rolling is finished in the temperature region of Ar3 point or higher, optionally annealing wherein the hot-rolled steel sheet is heated to 300° C. or higher after being cooled to 780° C. or lower, coiling higher than 400° C. or lower than 400° C., cold rolling the hot-rolled steel sheet or the annealed steel sheet, and annealing wherein the cold-rolled steel sheet is soaked in the temperature region of (Ac3 point?40° C.) or higher, cooling to 500° C. or lower and 300° C. or higher, and holding in that temperature region for 30 seconds or longer.Type: ApplicationFiled: July 2, 2012Publication date: August 28, 2014Applicant: NIPPON STEEL & SUMITOMO METAL CORPORATIONInventors: Jun Haga, Takuya Nishio, Masayuki Wakita, Yasuaki Tanaka, Norio Imai, Toshiro Tomida, Mitsuru Yoshida, Kengo Hata
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Publication number: 20140212686Abstract: A hot-dip galvanized cold-rolled steel sheet has a tensile strength of 750 MPa or higher, a composition consisting, in mass percent, of C: more than 0.10% and less than 0.25%, Si: more than 0.50% and less than 2.0%, Mn: more than 1.50% and 3.0% or less, and optionally containing one or more types of Ti, Nb, V, Cr, Mo, B, Ca, Mg, REM, and Bi, P: less than 0.050%, S: 0.010% or less, sol. Al: 0.50% or less, and N: 0.010% or less, and a main phase as a low-temperature transformation product and a second phase as retained austenite. The retained austenite volume fraction is more than 4.0% and less than 25.0% of the whole structure, and has an average grain size of less than 0.80 ?m. A number density of retained austenite grains having a grain size of 1.2 ?m or more is 3.0?10?2/?m2 or less.Type: ApplicationFiled: June 29, 2012Publication date: July 31, 2014Applicant: NIPPON STEEL & SUMITOMO METAL CORPORATIONInventors: Norio Imai, Masayuki Wakita, Takuya Nishio, Jun Haga, Kengo Hata, Yasuaki Tanaka, Mitsuru Yoshida, Hiroshi Takebayashi, Suguhiro Fukushima, Toshiro Tomida
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Publication number: 20140144553Abstract: A cold-rolled steel sheet having a refined structure in which grain growth during annealing is suppressed has a chemical composition containing, in mass percent, controlled amounts of carbon, manganese, niobium, titanium, vanadium, sol. Aluminum, chromium, molybdenum, boron, calcium, and REM and a microstructure which contains at least 50% by area of ferrite as a main phase, a second phase containing at least 10% by area of a low temperature transformation phase and 0-3% by area of retained austenite and which satisfies the following Equations (1)-(3), in addition to a particular texture, dm<2.7+10000/(5+300×C+50×Mn+4000×Nb+2000×Ti+400×V)2??(1), dm<4.0??(2), and ds?1.5??(3), wherein dm is the average grain diameter (?m) of ferrite defined by a high angle grain boundary having a tilt angle of at least 15°, and ds is the average grain diameter (?m) of the second phase.Type: ApplicationFiled: August 22, 2011Publication date: May 29, 2014Inventors: Kengo Hata, Toshiro Tomida, Norio Imai