Patents by Inventor Naoki Yoshinaga

Naoki Yoshinaga 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).

  • Publication number: 20110232807
    Abstract: High yield ratio high-strength thin steel sheet superior in weldability and ductility characterized by; being comprised of steel containing, by mass %, C: over 0.030 to less than 0.10%, Si: 0.30 to 0.80%, Mn: 1.7 to 3.2%, P: 0.001 to 0.02%, S: 0.0001 to 0.006%, Al: 0.060% or less, N: 0.0001 to 0.0070%, containing further Ti: 0.01 to 0.055%, Nb: 0.012 to 0.055%, Mo: 0.07 to 0.55%, B: 0.0005 to 0.0040%, and simultaneously statisfying 1.1?4×Ti(%)+20×Nb(%)+3×Mo(%)+300×B(%)?3.7, the balance comprised of iron and unavoidable impurities, and having a yield ratio of 0.64 to less than 0.92, a TS×El of 3320 or more, an YR×TS×El1/2 of 2320 or more, and a maximum tensile strength (TS) of 780 MPa or more.
    Type: Application
    Filed: June 3, 2011
    Publication date: September 29, 2011
    Applicant: NIPPON STEEL CORPORATION
    Inventors: Naoki Yoshinaga, Shunji Hiwatashi, Yasuharu Sakuma, Atsushi Itami
  • Publication number: 20110024004
    Abstract: The invention is directed to providing, for application in automobiles, construction materials, household appliances and the like, high-strength sheets excellent in formability properties such as hole expansibility and ductility, and also in fatigue resistance, characterized in comprising, in specified contents expressed in mass %, C, Si, Mn, P, S, Al, N and O and a balance of iron and unavoidable impurities, and having a steel sheet structure composed mainly of ferrite and hard structures, a crystal orientation difference between some ferrite adjacent to hard structures and the hard structures of less than 9°, and a maximum tensile strength of 540 MPa or greater.
    Type: Application
    Filed: April 9, 2009
    Publication date: February 3, 2011
    Inventors: Masafumi Azuma, Noriyuki Suzuki, Naoki Maruyama, Naoki Yoshinaga, Akinobu Murasato
  • Publication number: 20110017360
    Abstract: This hot-rolled steel sheet contains, in terms of mass%, C: 0.015% or more to less than 0.040%; Si: less than 0.05%; Mn: 0.9% or more to 1.8% or less; P: less than 0.02%; S: less than 0.01%; Al: less than 0.1%; N: less than 0.006%; and Ti: 0.05% or more to less than 0.11%, with the remainder being Fe and inevitable impurities, wherein Ti/C is in a range of 2.5 or more to less than 3.5, Nb, Zr, V, Cr, Mo, B and W are not included, a microstructure includes a mixed microstructure of polygonal ferrite and quasi-polygonal ferrite in a proportion of greater than 96%, a maximum tensile strength is 520 MPa or more and less than 720 MPa, an aging index AI is more than 15 MPa, a product of a hole expansion ratio (A) % and a total elongation (El) % is 2350 or more, and a fatigue limit is 200 MPa or more.
    Type: Application
    Filed: November 12, 2008
    Publication date: January 27, 2011
    Inventors: Naoki Yoshinaga, Masafumi Azuma, Yasuharu Sakuma, Naoki Maruyama
  • Publication number: 20110008647
    Abstract: This cold-rolled steel sheet includes, in terms of mass %, C: not less than 0.05% and not more than 0.095%, Cr: not less than 0.15% and not more than 2.0%, B: not less than 0.0003% and not more than 0.01%, Si: not less than 0.3% and not more than 2.0%, Mn: not less than 1.7% and not more than 2.6%, Ti: not less than 0.005% and not more than 0.14%, P: not more than 0.03%, S: not more than 0.01%, Al: not more than 0.1%, N: less than 0.005%, O: not less than 0.0005% and not more than 0.005%, and contains as the remainder, iron and unavoidable impurities, wherein the microstructure of the steel sheet includes mainly polygonal ferrite having a crystal grain size of not more than 4 ?m, and hard microstructures of bainite and martensite, the block size of the martensite is not more than 0.9 ?m, the Cr content within the martensite is 1.1 to 1.5 times the Cr content within the polygonal ferrite, and the tensile strength is at least 880 MPa.
    Type: Application
    Filed: March 26, 2009
    Publication date: January 13, 2011
    Inventors: Masafumi Azuma, Naoki Yoshinaga, Naoki Maruyama, Noriyuki Suzuki, Yasuharu Sakuma
  • Patent number: 7776161
    Abstract: The present invention provides a steel sheet excellent in workability, which may be used for components of an automobile or the like, and a method for producing the same. More specifically, according to one exemplary embodiment of the present invention, a steel sheet excellent in workability, including in mass, 0.08 to 0.25% C, 0.001 to 1.5% Si, 0.01 to 2.0% Mn, 0.001 to 0.06% P, at most 0.05% S, 0.001 to 0.007% N, 0.008 to 0.2% Al, at least 0.01% Fe. The steel sheet having an average r-value of at least 1.2, an r-value in the rolling direction of at least 1.3, an r-value in the direction of 45 degrees to the rolling direction of at least 0.9, and an r-value in the direction of a right angle to the rolling direction of at least 1.2.
    Type: Grant
    Filed: March 14, 2008
    Date of Patent: August 17, 2010
    Assignee: Nippon Steel Corporation
    Inventors: Naoki Yoshinaga, Nobuhiro Fujita, Manabu Takahashi, Koji Hashimoto, Shinya Sakamoto, Kaoru Kawasaki, Yasuhiro Shinohara, Takehide Senuma
  • Patent number: 7749343
    Abstract: The present invention provides a steel sheet excellent in workability, which may be used for components of an automobile or the like, and a method for producing the same. More specifically, according to one exemplary embodiment of the present invention, a steel sheet excellent in workability, including in mass, 0.08 to 0.25% C, 0.001 to 1.5% Si, 0.01 to 2.0% Mn, 0.001 to 0.06% P, at most 0.05% S, 0.001 to 0.007% N, 0.008 to 0.2% Al, at least 0.01% Fe. The steel sheet having an average r-value of at least 1.2, an r-value in the rolling direction of at least 1.3, an r-value in the direction of 45 degrees to the rolling direction of at least 0.9, and an r-value in the direction of a right angle to the rolling direction of at least 1.2.
    Type: Grant
    Filed: August 4, 2008
    Date of Patent: July 6, 2010
    Assignee: Nippon Steel Corporation
    Inventors: Naoki Yoshinaga, Nobuhiro Fujita, Manabu Takahashi, Koji Hashimoto, Shinya Sakamoto, Kaoru Kawasaki, Yasuhiro Shinohara, Takehide Senuma
  • Publication number: 20090255610
    Abstract: The invention provides a cold-rolled steel sheet excellent in paint bake hardenability and ordinary-temperature non-aging property comprising, in mass %, C: 0.0005-0.0040%, Si: 0.8% or less, Mn: 2.2% or less, S: 0.0005-0.009%, Cr: 0.4-1.3%, O: 0.003-0.020%, P: 0.045-0.12%, B: 0.0002-0.0010%, Al: 0.008% or less, N: 0.001-0.007%, and a balance of Fe and unavoidable impurities. Ultra-low-carbon steel retaining solute N and containing added Cr, P, B and O is used to produce hot-rolled and cold-rolled steel sheet and hot-dip galvanized cold-rolled steel sheet that exhibit both high paint bake hardenability and ordinary-temperature non-aging property.
    Type: Application
    Filed: October 5, 2005
    Publication date: October 15, 2009
    Inventors: Naoki Yoshinaga, Naoki Maruyama, Manabu Takahashi, Natsuko Sugiura
  • Patent number: 7534312
    Abstract: The present invention provides a steel sheet excellent in workability, which may be used for components of an automobile or the like, and a method for producing the same. More specifically, according to one exemplary embodiment of the present invention, a steel sheet excellent in workability, including in mass, 0.08 to 0.25% C, 0.001 to 1.5% Si, 0.01 to 2.0% Mn, 0.001 to 0.06% P, at most 0.05% S, 0.001 to 0.007% N, 0.008 to 0.2% Al, at least 0.01% Fe. The steel sheet having an average r-value of at least 1.2, an r-value in the rolling direction of at least 1.3, an r-value in the direction of 45 degrees to the rolling direction of at least 0.9, and an r-value in the direction of a right angle to the rolling direction of at least 1.2.
    Type: Grant
    Filed: June 27, 2002
    Date of Patent: May 19, 2009
    Assignee: Nippon Steel Corporation
    Inventors: Naoki Yoshinaga, Nobuhiro Fujita, Manabu Takahashi, Koji Hashimoto, Shinya Sakamoto, Kaoru Kawasaki, Yasuhiro Shinohara, Takehide Senuma
  • Patent number: 7485195
    Abstract: A high-strength hot-rolled steel sheet excellent in shape fixability having ferrite or bainite as the phase of the largest volume percentage, satisfying all of the following at least at ½ sheet thickness: a mean value of X-ray random intensity ratio in the orientation component group of {100}<011> to {223}<110> to X-ray random diffraction intensity ratio of at least 2.5; a mean value of X-ray random intensity ratio in the three crystal orientation components of {554}<225>, {111}<112>, and {111}<110> to X-ray random diffraction intensity ratio of 3.5 or less; an X-ray intensity ratio to X-ray random diffraction intensity ratio at {100}<011> of at least the X-ray random intensity to X-ray random diffraction intensity ratio at {211}<011>; and an X-ray random intensity ratio to X-ray random intensity ratio diffraction intensity ratio at {100}<011> of at least 2.
    Type: Grant
    Filed: June 28, 2004
    Date of Patent: February 3, 2009
    Assignees: Nippon Steel Corporation, Arcelor France
    Inventors: Natsuko Sugiura, Manabu Takahashi, Naoki Yoshinaga, Ken Kimura
  • Publication number: 20080308200
    Abstract: The present invention provides a steel sheet excellent in workability, which may be used for components of an automobile or the like, and a method for producing the same. More specifically, according to one exemplary embodiment of the present invention, a steel sheet excellent in workability, including in mass, 0.08 to 0.25% C, 0.001 to 1.5% Si, 0.01 to 2.0% Mn, 0.001 to 0.06% P, at most 0.05% S, 0.001 to 0.007% N, 0.008 to 0.2% Al, at least 0.01% Fe. The steel sheet having an average r-value of at least 1.2, an r-value in the rolling direction of at least 1.3, an r-value in the direction of 45 degrees to the rolling direction of at least 0.9, and an r-value in the direction of a right angle to the rolling direction of at least 1.2.
    Type: Application
    Filed: August 4, 2008
    Publication date: December 18, 2008
    Inventors: Naoki Yoshinaga, Nobuhiro Fujita, Manabu Takahashi, Koji Hashimoto, Shinya Sakamoto, Kaoru Kawasaki, Yasuhiro Shinohara, Takehide Senuma
  • Publication number: 20080295924
    Abstract: The present invention provides a steel sheet excellent in workability, which may be used for components of an automobile or the like, and a method for producing the same. More specifically, according to one exemplary embodiment of the present invention, a steel sheet excellent in workability, including in mass, 0.08 to 0.25% C, 0.001 to 1.5% Si, 0.01 to 2.0% Mn, 0.001 to 0.06% P, at most 0.05% S, 0.001 to 0.007% N, 0.008 to 0.2% Al, at least 0.01% Fe. The steel sheet having an average r-value of at least 1.2, an r-value in the rolling direction of at least 1.3, an r-value in the direction of 45 degrees to the rolling direction of at least 0.9, and an r-value in the direction of a right angle to the rolling direction of at least 1.2.
    Type: Application
    Filed: August 4, 2008
    Publication date: December 4, 2008
    Inventors: Naoki Yoshinaga, Nobuhiro Fujita, Manabu Takahashi, Koji Hashimoto, Shinya Sakamoto, Kaoru Kawasaki, Yasuhiro Shinohara, Takehide Senuma
  • Publication number: 20080166257
    Abstract: The present invention provides a steel sheet excellent in workability, which may be used for components of an automobile or the like, and a method for producing the same. More specifically, according to one exemplary embodiment of the present invention, a steel sheet excellent in workability, including in mass, 0.08 to 0.25% C, 0.001 to 1.5% Si, 0.01 to 2.0% Mn, 0.001 to 0.06% P, at most 0.05% S, 0.001 to 0.007% N, 0.008 to 0.2% Al, at least 0.01% Fe. The steel sheet having an average r-value of at least 1.2, an r-value in the rolling direction of at least 1.3, an r-value in the direction of 45 degrees to the rolling direction of at least 0.9, and an r-value in the direction of a right angle to the rolling direction of at least 1.2.
    Type: Application
    Filed: March 14, 2008
    Publication date: July 10, 2008
    Inventors: Naoki Yoshinaga, Nobuhiro Fujita, Manabu Takahashi, Koji Hashimoto, Shinya Sakamoto, Kaoru Kawasaki, Yasuhiro Shinohara, Takehide Senuma
  • Publication number: 20080008901
    Abstract: One aspect of the steel sheet having high Young's modulus includes in terms of mass %, C: 0.0005 to 0.30%, Si: 2.5% or less, Mn: 2.7 to 5.0%, P: 0.15% or less, S: 0.015% or less, Mo: 0.15 to 1.5%, B: 0.0006 to 0.01%, and Al: 0.15% or less, with the remainder being Fe and unavoidable impurities, wherein one or both of {110}<223> pole density and {110}<111> pole density in the ? sheet thickness layer is 10 or more, and a Young's modulus in a rolling direction is more than 230 GPa. Another aspect of the steel sheet having high Young's modulus includes, in terms of mass %, C: 0.0005 to 0.30%, Si: 2.5% or less, Mn: 0.1 to 5.0%, P: 0.15% or less, S: 0.015% or less, Al: 0.15% or less, N: 0.01% or less, and further comprises one or two or more of Mo: 0.005 to 1.5%, Nb: 0.005 to 0.20%, Ti: at least 48/14×N (mass %) and 0.2% or less, and B: 0.0001 to 0.01%, at a total content of 0.015 to 1.
    Type: Application
    Filed: July 27, 2005
    Publication date: January 10, 2008
    Applicant: Nippon Steel Corporation
    Inventors: Natsuko Sugiura, Naoki Yoshinaga, Shunji Hiwatashi, Manabu Takahashi, Koji Hanya, Nobuyoshi Uno, Ryoich Kanno, Akihiro Miyasaka, Takehide Senuma
  • Publication number: 20070089814
    Abstract: A high-strength hot-rolled steel sheet excellent in shape fixability having ferrite or bainite as the phase of the largest volume percentage, satisfying all of the following at least at ½ sheet thickness: a mean value of X-ray random intensity ratio in the orientation component group of {100}<011> to {223}<110> to X-ray random diffraction intensity ratio of at least 2.5; a mean value of X-ray random intensity ratio in the three crystal orientation components of {554}<225>, {111}<112>, and {111}<110> to X-ray random diffraction intensity ratio of 3.5 or less; an X-ray intensity ratio to X-ray random diffraction intensity ratio at {100}<011> of at least the X-ray random intensity to X-ray random diffraction intensity ratio at {211}<011>; and an X-ray random intensity ratio to X-ray random intensity ratio diffraction intensity ratio at {100}<011> of at least 2.
    Type: Application
    Filed: June 28, 2004
    Publication date: April 26, 2007
    Inventors: Natsuko Sugiura, Manabu Takahashi, Naoki Yoshinaga, Ken Kimura
  • Publication number: 20070029015
    Abstract: High yield ratio high-strength thin steel sheet D superior in weldability and ductility characterized by; being comprised of steel containing, by mass %, C: over 0.030 to less than 0.10%, Si: 0.30 to 0.80%, Mn: 1.7 to 3.2%, P: 0.001 to 0,02%, S: 0.0001 to 0.006%, Al: 0.060% or less, N: 0.0001 to 0.0070%, containing further c Ti: 0.01 to 0.055%, Nb: 0.012 to 0.055%, Mo: 0.07 to 0.55%, B: 0.0005 to 0.0040%, and simultaneously statisfying 1.1?14×Ti(%)+20×Nb(%)+3×Mo(%)+300×B(%)?3.7, the balance comprised of iron and unavoidable impurities, and having a yield ratio of 0.64 to less than 0.92, a TS×El of 3320 or more, an YR×TS×El1/2 of 2320 or more, and a maximum tensile strength (TS) of 780 MPa or more.
    Type: Application
    Filed: September 30, 2004
    Publication date: February 8, 2007
    Inventors: Naoki Yoshinaga, Shunji Hiwatashi, Yasuharu Sakuma, Atsushi Itami
  • Patent number: 6962631
    Abstract: A ferritic steel sheet wherein a mean value of X-ray random intensity ratios of a group of {100}<011> to {223}<110> orientations is 3.0 or more and a mean value of X-ray random intensity ratios of three crystal orientations of {554}<225>, {111}<112>, and {111}<110> is 3.5 or less and further at least one of the r values in a rolling direction and a direction at a right angle of that is 0.7 or less.
    Type: Grant
    Filed: September 21, 2001
    Date of Patent: November 8, 2005
    Assignee: Nippon Steel Corporation
    Inventors: Natsuko Sugiura, Naoki Yoshinaga, Manabu Takahashi, Tohru Yoshida
  • Patent number: 6866725
    Abstract: The present invention is a high strength steel pipe excellent in formability in hydroforming and similar forming methods, characterized by: containing, in mass, C of 0.0005 to 0.30%, Si of 0.001 to 2.0%, Mn of 0.01 to 3.0% and appropriate amounts of other elements if necessary, with the balance consisting of Fe and unavoidable impurities; and an average for the ratios of the X-ray strength in the orientation component group of {110}<110> to {111}<110> to random X-ray diffraction strength on a plane at the wall thickness center being 2.0 or more and/or a ratio of the X-ray strength in the orientation component of {110}<110> to random X-ray diffraction strength on the plane at the wall thickness center being 3.0 or more.
    Type: Grant
    Filed: February 28, 2001
    Date of Patent: March 15, 2005
    Assignee: Nippon Steel Corporation
    Inventors: Nobuhiro Fujita, Naoki Yoshinaga, Manabu Takahashi, Hitoshi Asahi, Yasuhiro Shinohara, Yasushi Hasegawa
  • Publication number: 20040238081
    Abstract: The present invention provides a steel sheet excellent in workability, which may be used for components of an automobile or the like, and a method for producing the same. More specifically, according to one exemplary embodiment of the present invention, a steel sheet excellent in workability, including in mass, 0.08 to 0.25% C, 0.001 to 1.5% Si, 0.01 to 2.0% Mn, 0.001 to 0.06% P, at most 0.05% S, 0.001 to 0.007% N, 0.008 to 0.2% Al, at least 0.01% Fe. The steel sheet having an average r-value of at least 1.2, an r-value in the rolling direction of at least 1.3, an r-value in the direction of 45 degrees to the rolling direction of at least 0.9, and an r-value in the direction of a right angle to the rolling direction of at least 1.2.
    Type: Application
    Filed: February 24, 2004
    Publication date: December 2, 2004
    Inventors: Naoki Yoshinaga, Nobuhiro Fujita, Manabu Takahashi, Koji Hashimoto, Shinya Sakamoto, Kaoru Kawasaki, Yasuhiro Shinohara, Takehide Senuma
  • Publication number: 20040069382
    Abstract: The present invention provides a thin steel sheet, for automobile use, excellent in notch-fatigue strength, and a method for producing said steel sheet. Specifically, the present invention is a thin steel sheet for automobile use excellent in notch-fatigue strength, said steel sheet containing, in mass, 0.01 to 0.3% C, 0.01 to 2% Si, 0.05 to 3% Mn, 0.1% or less P, 0.01% or less S and 0.005 to 1% Al, with the balance consisting of Fe and unavoidable impurities, characterized in that, on a plane at an arbitrary depth within 0.
    Type: Application
    Filed: August 22, 2003
    Publication date: April 15, 2004
    Inventors: Tatsuo Yokoi, Natsuko Sugiura, Naoki Yoshinaga, Koichi Tsuchihashi, Takehiro Nakamoto
  • Patent number: 6706419
    Abstract: To provide a steel sheet excellent in painting bake hardenability and anti aging property at room temperature: containing, in mass, 0.0001 to 0.20% of C, 2.0% or less of Si, 3.0% or less of Mn, 0.15% or less of P, 0.015% or less of S, and, in addition, 010% or less of Al and 0.001 to 0.10% of N so as to satisfy the expression 0.52Al/N<5 and, further, one or more of 2.5% or less of Cr, 1.0% or less of Mo and 0.1% or less of V so as to satisfy the expression (Cr+3.5MO+39V) ≧0.1, with the balance consisting of Fe and unavoidable impurities; having the value of BH170, evaluated after applying a 2% tensile deformation and then a heat treatment at 170° C. for 20 min., being 45 MPa or more, and any of the value of BH160, evaluated after applying a 2% tensile deformation and then a heat treatment at 160° C. for 10 min., and the value of BH150, evaluated after applying a 2% tensile deformation and then a heat treatment at 150° C. for 10 min.
    Type: Grant
    Filed: April 4, 2002
    Date of Patent: March 16, 2004
    Assignee: Nippon Steel Corporation
    Inventors: Naoki Yoshinaga, Manabu Takahashi, Natsuko Sugiura, Akihiro Miyasaka, Masaaki Sugiyama