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: 20030196735
    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: Application
    Filed: March 20, 2003
    Publication date: October 23, 2003
    Inventors: Natsuko Sugiura, Naoki Yoshinaga, Takahashi Manabu, Yoshida Tohru
  • Patent number: 6632296
    Abstract: The present invention provides a steel pipe excellent in formability during hydraulic forming and the like and a method to produce the same, and more specifically: a steel pipe excellent in formability having an r-value of 1.4 or larger in the axial direction of the steel pipe, and the property that the average of the ratios of the X-ray intensity in the orientation component group of {110}<110> to {332}<110> on the plane at the center of the steel pipe wall thickness to the random X-ray intensity is 3.5 or larger, and/or the ratio of the X-ray intensity in the orientation component of {110}<110> on the plane at the center of the steel pipe wall thickness to the random X-ray intensity is 5.
    Type: Grant
    Filed: February 6, 2002
    Date of Patent: October 14, 2003
    Assignee: Nippon Steel Corporation
    Inventors: Naoki Yoshinaga, Nobuhiro Fujita, Manabu Takahashi, Yasuhiro Shinohara, Tohru Yoshida, Natsuko Sugiura
  • Publication number: 20030131909
    Abstract: The present invention provides a steel pipe excellent in formability during hydraulic forming and the like and a method to produce the same, and more specifically: a steel pipe excellent in formability having an r-value of 1.4 or larger in the axial direction of the steel pipe, and the property that the average of the ratios of the X-ray intensity in the orientation component group of {110}<110> to {332}<110> on the plane at the center of the steel pipe wall thickness to the random X-ray intensity is 3.5 or larger, and/or the ratio of the X-ray intensity in the orientation component of {110}<110> on the plane at the center of the steel pipe wall thickness to the random X-ray intensity is 5.
    Type: Application
    Filed: February 6, 2002
    Publication date: July 17, 2003
    Inventors: Naoki Yoshinaga, Nobuhiro Fujita, Manabu Takashi, Yasuhiro Shinohara, Tohru Yoshida, Natsuko Sugiura
  • Publication number: 20030116238
    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: Application
    Filed: August 27, 2002
    Publication date: June 26, 2003
    Inventors: Nobuhiro Fujita, Naoki Yoshinaga, Manabu Takahashi, Hitoshi Asahi, Yasuhiro Shinohara, Yasushi Hasegawa
  • Publication number: 20020197508
    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 BE170, 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: Application
    Filed: April 4, 2002
    Publication date: December 26, 2002
    Inventors: Naoki Yoshinaga, manabu Takahashi, Natsuko Sugiura, Akihiro Miyasaka, Masaaki Sugiyama
  • Patent number: 5954896
    Abstract: According to the present invention, an ultra low carbon steel with Nb, Ti, or Nb-Ti added thereto is used as a material, and (% S as MnS)/(total S content) is regulated to not more than 0.2 with (% C as carbosulfide)/(total C content) being regulating to not more than 0.7, thereby efficiently precipitating carbosulfide in a .gamma. temperature region during hot rolling and thus reducing the amount of C in solid solution to ensure the homogeneity of the material over the whole length of a coil and to markedly improve the workability.
    Type: Grant
    Filed: October 18, 1996
    Date of Patent: September 21, 1999
    Assignee: Nippon Steel Corporation
    Inventors: Kazuo Koyama, Masayoshi Suehiro, Naoki Yoshinaga, Natsuko Hashimoto
  • Patent number: 5690755
    Abstract: The present invention provides a cold-rolled steel sheet and a hot-dip galvanized steel sheet having good bake hardenability, non-aging properties at room temperature and good formability and a process for producing the same. An extra low carbon steel or an extra low carbon steel containing at least one element selected from Ti and Nb is annealed at a temperature of not lower than the AC.sub.3 transformation point to bring the structure after annealing to a structure of low-temperature transformation products. This makes it possible to provide a steel sheet that has a combination of high paint-bake hardenability and non-aging properties at room temperature and is excellent also in formability in respect of average r value (deep drawability) and elongation (punch stretchability). In particular, with respect to paint-bake hardenability, a BH property on a high level up to about 10 kgf/mm.sup.
    Type: Grant
    Filed: September 11, 1996
    Date of Patent: November 25, 1997
    Assignee: Nippon Steel Corporation
    Inventors: Naoki Yoshinaga, Kohsaku Ushioda, Osamu Akisue, Yoshikazu Matsumura, Kunio Nishimura
  • Patent number: 5486241
    Abstract: The present invention provides a non-aging at room temperature ferritic single-phase cold-rolled steel sheet or hot-dip galvanized steel sheet for deep drawing and having excellent fabrication embrittlement resistance and paint-bake hardenability, by heating a slab comprising, in terms of % by weight, 0.0001 to 0.0015% of C, not more than 1.2% of Si, 0.03 to 3.0% of Mn, 0.01 to 0.15% of P, 0.0010 to 0.020% of S, 0.005 to 0.1% of Al, 0.0001 to 0.0080% of N and 0.0001 to 0.0030% of B and optionally 0.1 to 3% of Cr with the balance consisting of Fe and unavoidable impurities, hot-rolling the heated slab at a finishing temperature of not lower than (Ar.sub.3 --100).degree. C., cooling the hot-rolled coil within 1 sec after the hot rolling at a rate of not less than 50.degree. C./sec from the finishing temperature to a temperature in the range of from 600.degree. to 750.degree. C.
    Type: Grant
    Filed: June 29, 1994
    Date of Patent: January 23, 1996
    Assignee: Nippon Steel Corporation
    Inventors: Kohsaku Ushioda, Naoki Yoshinaga, Yoshikazu Matsumura, Osamu Akisue, Kunio Nishimura, Hidekuni Murakami
  • Patent number: 5470403
    Abstract: The present invention provides a cold rolled steel sheet and a hot dip zinc-coated cold rolled steel sheet excellent in paint bake hardenability, non-aging properties and formability, and a process for producing the same. In the present invention, an extremely low carbon steel or extremely low carbon steel containing at least one element selected from the group consisting of Ti and Nb is used as a base steel, and Mn and Cr are positively added thereto, whereby the resultant steel has a mixed structure after annealing. Accordingly, there can be obtained a steel sheet having both a high paint bake hardenability and non-aging properties, and being excellent in formability such as an average r-value (deep drawability). With regard to the paint bake hardenability, the present invention may provide a cold rolled steel sheet and a hot dip zinc-coated cold rolled steel sheet to which paint bake hardening may be optionally imparted in an amount as large as about 10 kgf/mm.sup.
    Type: Grant
    Filed: February 18, 1994
    Date of Patent: November 28, 1995
    Assignee: Nippon Steel Corporation
    Inventors: Naoki Yoshinaga, Kohsaku Ushioda, Osamu Akisue, Kunio Nishimura
  • Patent number: 5384206
    Abstract: A high-strength cold-rolled steel strip or a molten zinc-plated high-strength cold-rolled steel strip which have a low yield strength, containing, by weight, of 0.0005-0.01% C, not more than 0.8% Si, more than 0.5% but not more than 3.0% Mn, 0.01-0.12%: P. 0.0010-0.015% S, 0.01-0.1% Al, 0.0005-0.0060% N, not less than 0.0001% but less than 0.005-0.1% the content of Nb being made to satisfy Nb .gtoreq.93/12 (C-0.0015), or instead of 0.005-0.1% Nb, 0.0005-0.1% Ti and 0.003-0.1% Nb, the content of Nb and the content of Ti being made satisfy, Ti.gtoreq.3.42N, and the balance Fe and incidental impurities is provided. Another steel strip or molten zinc-plated strip is provided that contains 0.2-3.0% Cr but does not require B, and includes both Ti and Nb. The method of producing such is also provided.
    Type: Grant
    Filed: September 3, 1993
    Date of Patent: January 24, 1995
    Assignee: Nippon Steel Corporation
    Inventors: Kohsaku Ushioda, Naoki Yoshinaga, Osamu Akisue
  • Patent number: 5074924
    Abstract: A process for producing a non-aging galvanized steel sheet having good formability in a continuous galvanizing production line, which comprises heating a low carbon, Al-killed cold rolled steel sheet at a temperature not lower than a recrystallizing temperature, reducing the surface of the steel sheet thus heated in a reducing atmosphere, cooling the steel sheet to a temperature (T.sub.E) ranging from 200.degree. to 350.degree. C. from a temperature not lower than 600.degree. C. at a cooling rate not less than 30.degree. C/s, holding the steel sheet at the temperature (T.sub.E) for 0 to less than 10 seconds, reheating the steel sheet to a temperature ranging from 430.degree. to 500.degree. C. at a heating rate not less than 10.degree. C/s, immersing the steel sheet into a molten zinc bath, cooling the steel sheet thus galvanized to a temperature not higher than 370.degree. C., and subjecting the steel sheet to an overaging treatment to a temperature range from 250.degree. to 320.degree. C.
    Type: Grant
    Filed: June 21, 1990
    Date of Patent: December 24, 1991
    Assignee: Nippon Steel Corporation
    Inventors: Kohsaku Ushioda, Osamu Akisue, Naoki Yoshinaga, Tomohisa Katayama, Masakazu Oshimi