Patents by Inventor Katsuhiro Sasai
Katsuhiro Sasai 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: 10987730Abstract: A continuous casting apparatus for a multilayered slab includes a ladle having a molten steel supply nozzle; a tundish having a first retention portion that receives supply of the molten steel from the ladle through the molten steel supply nozzle and has a first immersion nozzle and a second retention portion that is adjacent to the first retention portion with a flow path interposed therebetween and has a second immersion nozzle; an addition mechanism that adds a predetermined element to the molten steel in the second retention portion; and a casting mold that receives supply of the molten steel from the tundish.Type: GrantFiled: October 31, 2016Date of Patent: April 27, 2021Assignee: NIPPON STEEL CORPORATIONInventors: Hiroshi Harada, Masashi Sakamoto, Yui Ito, Katsuhiro Sasai
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Publication number: 20180304349Abstract: A continuous casting apparatus for a multilayered slab includes a ladle having a molten steel supply nozzle; a tundish having a first retention portion that receives supply of the molten steel from the ladle through the molten steel supply nozzle and has a first immersion nozzle and a second retention portion that is adjacent to the first retention portion with a flow path interposed therebetween and has a second immersion nozzle; an addition mechanism that adds a predetermined element to the molten steel in the second retention portion; and a casting mold that receives supply of the molten steel from the tundish.Type: ApplicationFiled: October 31, 2016Publication date: October 25, 2018Applicant: NIPPON STEEL & SUMITOMO METAL CORPORATIONInventors: Hiroshi HARADA, Masashi SAKAMOTO, Yui ITO, Katsuhiro SASAI
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Patent number: 9650690Abstract: A high-strength steel sheet includes: 0.03 to 0.20% of C, 0.08 to 1.5% of Si, 0.5 to 3.0% of Mn, 0.05% or less of P, 0.0005% or more of S, 0.008 to 0.20% of acid-soluble Ti, 0.0005 to 0.01% of N, more than 0.01% of acid-soluble Al, and 0.001 to 0.04% of one or both of Ce and La in terms of mass %; and the balance including Fe and inevitable impurities. The ratio of (Ce+La)/acid-soluble Al is equal to or more than 0.1 and the ratio of (Ce+La)/S is in the range of 0.4 to 50 in a mass base, and the density of the number of inclusions, having a circle equivalent diameter of 2 ?m or less, which are present in the steel sheet is equal to or more than 15/mm2.Type: GrantFiled: June 15, 2009Date of Patent: May 16, 2017Assignee: NIPPON STEEL & SUMITOMO METAL CORPORATIONInventors: Kenichi Yamamoto, Katsuhiro Sasai, Hideaki Yamamura, Hiroshi Harada, Kaoru Kawasaki
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Patent number: 9017492Abstract: The present invention provides ultralow carbon thin gauge steel sheet and a method for producing the same where coalescence and growth of inclusions in the molten steel are prevented and the inclusions are finely dispersed in the steel sheet, whereby surface defects and cracks at the time of press forming are prevented, growth of recrystallized grains at the time of continuous annealing is promoted, and a high r value (r value?2.0) and elongation (total elongation?50%) are exhibited, that is, ultralow carbon thin gauge steel sheet excellent in surface conditions, formability, and workability comprised of, by mass %, 0.00030.003%?C?0.003%, Si?0.01%, Mn?0.1%, P?0.02%, S?0.01%, 0.0005%?N?0.0025%, 0.01%?acid soluble Ti?0.07%, acid soluble Al?0.003%, and 0.002%?La+Ce+Nd?0.02% and a balance of iron and unavoidable impurities, said steel sheet characterized by containing at least cerium oxysulfite, lanthanum oxysulfite, and neodymium oxysulfite.Type: GrantFiled: August 24, 2010Date of Patent: April 28, 2015Assignee: Nippon Steel & Sumitomo Metal CorporationInventors: Katsuhiro Sasai, Wataru Ohashi
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Publication number: 20120261085Abstract: A method of producing an extremely low carbon steel cast slab characterized by casting molten steel obtained by reducing the carbon concentration of the molten steel to 0.005 mass % or less, then adding Cu, Nb, and B to the molten steel, furthermore, and adjusting the concentration of dissolved oxygen in the molten steel to 0.01 mass % to 0.06 mass % and extremely low carbon steel plate comprised of steel containing C: 0.005 mass % or less, acid soluble Al: 0.005 mass % or less, and further Cu, Nb, and B, characterized in that the steel has fine oxides of a diameter of 0.5 ?m to 30 ?m dispersed in it in an amount of 1000 particles/cm2 to 1,000,000 particles/cm2.Type: ApplicationFiled: June 22, 2012Publication date: October 18, 2012Applicant: Nippon Steel CorporationInventors: Katsuhiro Sasai, Wataru Ohashi
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Patent number: 8048197Abstract: The present invention provides a low carbon steel sheet and a low carbon steel slab on which formation of surface defects can be surely prevented by preventing aggregation of inclusions in the molten steel and finely dispersing inclusions in the steel sheet or slab, and a process for producing the steel sheet and slab. The present invention provides a process comprising the steps of decarburizing a molten steel so as to produce a carbon concentration of up to 0.01% by mass, pre-deoxidizing the molten steel by adding Al thereto so as to produce a dissolved oxygen concentration from 0.01 to 0.04% by mass, adding thereto Ti and at least La and/or Ce, and casting the molten steel, and a steel sheet and a steel slab obtained by the process.Type: GrantFiled: February 15, 2008Date of Patent: November 1, 2011Assignee: Nippon Steel CorporationInventors: Katsuhiro Sasai, Wataru Ohashi, Tooru Matsumiya, Yoshiaki Kimura, Junji Nakashima
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Publication number: 20110076512Abstract: A high-strength steel sheet includes: 0.03 to 0.20% of C, 0.08 to 1.5% of Si, 0.5 to 3.0% of Mn, 0.05% or less of P, 0.0005% or more of S, 0.008 to 0.20% of acid-soluble Ti, 0.0005 to 0.01% of N, more than 0.01% of acid-soluble Al, and 0.001 to 0.04% of one or both of Ce and La in terms of mass %; and the balance including Fe and inevitable impurities. The ratio of (Ce+La)/acid-soluble Al is equal to or more than 0.1 and the ratio of (Ce+La)/S is in the range of 0.4 to 50 in a mass base, and the density of the number of inclusions, having a circle equivalent diameter of 2 ?m or less, which are present in the steel sheet is equal to or more than 15/mm2.Type: ApplicationFiled: June 15, 2009Publication date: March 31, 2011Inventors: Kenichi Yamamoto, Katsuhiro Sasai, Hideaki Yamamura, Hiroshi Harada, Kaoru Kawasaki
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Publication number: 20100319816Abstract: The present invention provides ultralow carbon thin gauge steel sheet and a method for producing the same where coalescence and growth of inclusions in the molten steel are prevented and the inclusions are finely dispersed in the steel sheet, whereby surface defects and cracks at the time of press forming are prevented, growth of recrystallized grains at the time of continuous annealing is promoted, and a high r value (r value?2.0) and elongation (total elongation?0%) are exhibited, that is, ultralow carbon thin gauge steel sheet excellent in surface conditions, formability, and workability comprised of, by mass %, 0.00030.003%?C?0.003%, Si?0.01%, Mn?0.1%, P?0.02%, S?0.01%, 0.0005%?N?0.0025%, 0.01%?acid soluble Ti?0.07%, acid soluble Al?0.003%, and 0.002%?La+Ce+Nd?0.02% and a balance of iron and unavoidable impurities, said steel sheet characterized by containing at least cerium oxysulfite, lanthanum oxysulfite, and neodymium oxysulfite.Type: ApplicationFiled: August 24, 2010Publication date: December 23, 2010Applicant: NIPPON STEEL CORPORATIONInventors: Katsuhiro Sasai, Wataru Ohashi
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Publication number: 20100158746Abstract: A method of producing an extremely low carbon steel cast slab characterized by casting molten steel obtained by reducing the carbon concentration of the molten steel to 0.005 mass % or less, then adding Cu, Nb, and B to the molten steel, furthermore, and adjusting the concentration of dissolved oxygen in the molten steel to 0.01 mass % to 0.06 mass % and extremely low carbon steel plate comprised of steel containing C: 0.005 mass % or less, acid soluble Al: 0.005 mass % or less, and further Cu, Nb, and B, characterized in that the steel has fine oxides of a diameter of 0.5 ?m to 30 ?m dispersed in it in an amount of 1000 particles/cm2 to 1,000,000 particles/cm2.Type: ApplicationFiled: February 16, 2006Publication date: June 24, 2010Inventors: Katsuhiro Sasai, Wataru Ohashi
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Publication number: 20090317285Abstract: The present invention provides high strength hot rolled steel plate superior in stretch flange formability and fatigue characteristics comprising steel plate containing C: 0.03 to 0.20%, Si: 0.08 to 1.5%, Mn: 1.0 to 3.0%, P: 0.05% or less, S: 0.0005% or more, N: 0.0005 to 0.01%, acid soluble Al: 0.01% or less, acid soluble Ti: less than 0.008%, and a total of one or both of Ce or La: 0.0005 to 0.04%, having a balance of iron and unavoidable impurities and having a number ratio of stretched inclusions present in the steel plate having a circle equivalent diameter of 1 ?m or more and a long axis/short axis of 5 or more of 20% or less.Type: ApplicationFiled: March 2, 2007Publication date: December 24, 2009Inventors: Katsuhiro Sasai, Wataru Ohashi, Kenichi Yamamoto, Kaoru Kawasaki, Hiroshi Harada
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Publication number: 20090288799Abstract: A method of production of an ultralow carbon cast slab characterized by adding Ti to molten steel decarburized to a carbon concentration of 0.01 mass % or less, further adding at least one of Ce, La, and Nd, and using an immersion nozzle to inject the above molten steel from a tundish to a casting mold for continuous casting while maintaining a flow rate of Ar gas blown from any location in a range from a tundish upper nozzle to discharge ports of said immersion nozzle at 3 Nl (normal liter)/min or less.Type: ApplicationFiled: October 27, 2006Publication date: November 26, 2009Inventors: Masafumi Miyazaki, Akihiro Matsuzawa, Katsuhiro Sasai, Wataru Ohashi, Yasuhiko Ohtani, Katsunori Yamada, Masahiro Doki, Go Hirata, Yoshiaki Kimura, Hajime Hasegawa
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Publication number: 20080149298Abstract: The present invention provides a low carbon steel sheet and a low carbon steel slab on which formation of surface defects can be surely prevented by preventing aggregation of inclusions in the molten steel and finely dispersing inclusions in the steel sheet or slab, and a process for producing the steel sheet and slab. The present invention provides a process comprising the steps of decarburizing a molten steel so as to produce a carbon concentration of up to 0.01% by mass, pre-deoxidizing the molten steel by adding Al thereto so as to produce a dissolved oxygen concentration from 0.01 to 0.04% by mass, adding thereto Ti and at least La and/or Ce, and casting the molten steel, and a steel sheet and a steel slab obtained by the process.Type: ApplicationFiled: February 15, 2008Publication date: June 26, 2008Applicant: Nippon Steel CorporationInventors: Katsuhiro Sasai, Wataru Ohashi, Tooru Matsumiya, Yoshiaki Kimura, Junji Nakashima
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Patent number: 7347904Abstract: The present invention provides a low carbon steel sheet and a low carbon steel slab on which formation of surface defects can be surely prevented by preventing aggregation of inclusions in the molten steel and finely dispersing inclusions in the steel sheet or slab, and a process for producing the steel sheet and slab. The present invention provides a process comprising the steps of decarburizing a molten steel so as to produce a carbon concentration of up to 0.01% by mass, pre-deoxidizing the molten steel by adding Al thereto so as to produce a dissolved oxygen concentration from 0.01 to 0.04% by mass, adding thereto Ti and at least La and/or Ce, and casting the molten steel, and a steel sheet and a steel slab obtained by the process.Type: GrantFiled: June 28, 2002Date of Patent: March 25, 2008Assignee: Nippon Steel CorporationInventors: Katsuhiro Sasai, Wataru Ohashi, Tooru Matsumiya, Yoshiaki Kimura, Junji Nakashima
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Publication number: 20070079910Abstract: The present invention provides ultralow carbon thin gauge steel sheet and a method for producing the same where coalescence and growth of inclusions in the molten steel are prevented and the inclusions are finely dispersed in the steel sheet, whereby surface defects and cracks at the time of press forming are prevented, growth of recrystallized grains at the time of continuous annealing is promoted, and a high r value (r value?2.0) and elongation (total elongation?50%) are exhibited, that is, ultralow carbon thin gauge steel sheet excellent in surface conditions, formability, and workability comprised of, by mass %, 0.0003%?C?0.003%, Si <0.01%, Mn ?0.1%, P?0.02%, S?0.01%, 0.0005%?N?0.0025%, 0.01%?acid soluble Ti?0.07%, acid soluble Al ?0.003%, and 0.002%?La+Ce+Nd?0.02% and a balance of iron and unavoidable impurities, said steel sheet characterized by containing at least cerium oxysulfite, lanthanum oxysulfite, and neodymium oxysulfite.Type: ApplicationFiled: November 4, 2004Publication date: April 12, 2007Applicant: NIPPON STEEL CORPORATIONInventors: Katsuhiro Sasai, Wataru Ohashi
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Publication number: 20040168749Abstract: The present invention provides a low carbon steel sheet and a low carbon steel slab on which formation of surface defects can be surely prevented by preventing aggregation of inclusions in the molten steel and finely dispersing inclusions in the steel sheet or slab, and a process for producing the steel sheet and slab. The present invention provides a process comprising the steps of decarburizing a molten steel so as to produce a carbon concentration of up to 0.01% by mass, pre-deoxidizing the molten steel by adding Al thereto so as to produce a dissolved oxygen concentration from 0.01 to 0.04% by mass, adding thereto Ti and at least La and/or Ce, and casting the molten steel, and a steel sheet and a steel slab obtained by the process.Type: ApplicationFiled: December 22, 2003Publication date: September 2, 2004Inventors: Katsuhiro Sasai, Wataru Ohashi, Tooru Matsumiya, Yoshiaki Kimura, Junji Nakashima
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Patent number: 6773829Abstract: A cast slab has a negative segregation zone composed of a multilayer structure of negative segregation layers disposed between dendrite or crystalline layers. The dendrite or crystalline layers are a deflection structure caused by vibration during formation of the cast slab. The negative segregation layers have a distance between them of not more than 2 mm and the number of negative segregation layers is not less than 3. The cast slab has an equi-axed crystal ratio of not less than 50% inside the multilayer negative segregation zone.Type: GrantFiled: March 7, 2002Date of Patent: August 10, 2004Assignee: Nippon Steel CorporationInventors: Katsuhiro Sasai, Eiichi Takeuchi, Hiroshi Harada, Hajime Hasegawa, Takehiko Toh, Keisuke Fujisaki
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Patent number: 6443219Abstract: The present invention provides a continuous casting method in which vibration is given to molten metal by a shifting magnetic field so that the equi-axed crystal ratio can be enhanced and the equi-axed crystals can be made fine without generating surface defects caused by powder trapping. Further, the present invention provides an apparatus to which the continuous casting method is applied. Furthermore the present invention provides a cast slab produced by the above method and apparatus.Type: GrantFiled: August 9, 1999Date of Patent: September 3, 2002Assignee: Nippon Steel CorporationInventors: Katsuhiro Sasai, Eiichi Takeuchi, Hiroshi Harada, Hajime Hasegawa, Takehiko Toh, Keisuke Fujisaki
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Publication number: 20020096308Abstract: The present invention provides a continuous casting method in which vibration is given to molten metal by a shifting magnetic field so that the equi-axed crystal ratio can be enhanced and the equi-axed crystals can be made fine without generating surface defects caused by powder trapping. Further, the present invention provides an apparatus to which the continuous casting method is applied. Furthermore, the present invention provides a cast slab produced by the above method and apparatus.Type: ApplicationFiled: March 25, 2002Publication date: July 25, 2002Applicant: Nippon Steel CorporationInventors: Katsuhiro Sasai, Eiichi Takeuchi, Hiroshi Harada, Hajime Hasegawa, Takehiko Toh, Keisuke Fujisaki
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Publication number: 20020092642Abstract: The present invention provides a continuous casting method in which vibration is given to molten metal by a shifting magnetic field so that the equi-axed crystal ratio can be enhanced and the equi-axed crystals can be made fine without generating surface defects caused by powder trapping. Further, the present invention provides an apparatus to which the continuous casting method is applied. Furthermore, the present invention provides a cast slab produced by the above method and apparatus.Type: ApplicationFiled: March 7, 2002Publication date: July 18, 2002Applicant: Nippon Steel CorporationInventors: Katsuhiro Sasai, Eiichi Takeuchi, Hiroshi Harada, Hajime Hasegawa, Takehiko Toh, Keisuke Fujisaki