Patents by Inventor Makoto Okonogi

Makoto Okonogi 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).

  • Patent number: 11203797
    Abstract: A predetermined composition is had, when a C content is represented by (C %), in a case of (C %) being not less than 0.35% nor more than 0.65%, a volume fraction of pearlite is 64×(C %)+52% or more, and in a case of (C %) being greater than 0.65% and 0.85% or less, the volume fraction of pearlite is not less than 94% nor more than 100%, and a structure of the other portion is composed of one or two of proeutectoid ferrite and bainite. Further, in a region to a depth of 1.0 mm from a surface, a volume fraction of pearlite block having an aspect ratio of 2.0 or more is not less than 70% nor more than 95%, and a volume fraction of pearlite having an angle between an axial direction and a lamellar direction on a cross section parallel to the axial direction of 40° or less is 60% or more with respect to all pearlite.
    Type: Grant
    Filed: March 27, 2020
    Date of Patent: December 21, 2021
    Assignee: NIPPON STEEL CORPORATION
    Inventors: Makoto Okonogi, Shingo Yamasaki, Akifumi Kawana, Hideaki Gotohda
  • Publication number: 20200370142
    Abstract: A drawn steel wire has a predetermined chemical composition; in a region of the drawn steel wire that is closer to an axis line than a depth of 100 ?m from a surface of the drawn steel wire in a lengthwise-section that includes the axis line of the drawn steel wire, a metallographic structure includes 90% or more of a drawn pearlite by an area ratio; in a region of the drawn steel wire that is the depth of 100 ?m from the surface of the drawn steel wire in the lengthwise-section, the metallographic structure includes 70% or more of the drawn pearlite by the area ratio; when D in units of millimeters represents a diameter of the drawn steel wire, ?HV represents a standard deviation of a Vickers hardness of the surface of the drawn steel wire, and Rp0.2 represents a yield strength of the drawn steel wire, ?HV<(?9500×ln(D)+30000) exp(?0.003×Rp0.2) is satisfied, and a tensile strength TS of the drawn steel wire is 1770 MPa or higher.
    Type: Application
    Filed: July 14, 2017
    Publication date: November 26, 2020
    Applicant: NIPPON STEEL & SUMITOMO METAL CORPORATION
    Inventors: Toshiyuki MANABE, Daisuke HIRAKAMI, Makoto OKONOGI, Naoki MATSUI, Arata ISO
  • Publication number: 20200354810
    Abstract: A high-strength steel wire includes a predetermined chemical composition. In the high-strength steel wire, a metallographic microstructure includes a pearlite structure of not less than 95% by area, an average aspect ratio R of a pearlite block, measured in a surface layer in a cross section in an axial direction including an axis of the steel wire, is 2.0 or more, assuming that a diameter of the steel wire is D, a ratio of an average aspect ratio measured in the surface layer to an average aspect ratio measured at a position of 0.25D is 1.1 or more in the cross section in the axial direction including the axis of the steel wire, and a tensile strength of the steel wire is 1,800 MPa or more.
    Type: Application
    Filed: July 28, 2017
    Publication date: November 12, 2020
    Applicant: Nippon Steel & Sumitomo Metal Corporation
    Inventors: Makoto OKONOGI, Naoki MATSUI
  • Patent number: 10808305
    Abstract: This invention provides a high-strength PC steel wire having a chemical composition containing, in mass %, C: 0.90 to 1.10%, Si: 0.80 to 1.50%, Mn: 0.30 to 0.70%, P: 0.030% or less, S: 0.030% or less, Al: 0.010 to 0.070%, N: 0.0010 to 0.010%, Cr: 0 to 0.50%, V: 0 to 0.10%, B: 0 to 0.005%, Ni: 0 to 1.0%, Cu: 0 to 0.50%, and the balance: Fe and impurities. A ratio between the Vickers hardness (HvS) at a location (surface layer) that is 0.1D [D: diameter of steel wire] from the surface of the steel wire and the Vickers hardness (HvI) of a region on the inner side relative to the surface layer satisfies the formula [1.10<HvS/HvI?1.15]. An average carbon concentration in a region from the surface to a depth of 10 ?m (outermost layer region) of the steel wire is 0.8 times or less a carbon concentration of the steel wire. The steel micro-structure in the region on the inner side relative to the outermost layer region contains, in area %, a pearlite structure: 95% or more.
    Type: Grant
    Filed: July 20, 2016
    Date of Patent: October 20, 2020
    Assignees: NIPPON STEEL CORPORATION, SUMITOMO ELECTRIC INDUSTRIES, LTD.
    Inventors: Makoto Okonogi, Daisuke Hirakami, Masato Yamada, Katsuhito Oshima, Shuichi Tanaka
  • Patent number: 10752974
    Abstract: This invention provides a high-strength PC steel wire having a chemical composition containing, in mass %, C: 0.90 to 1.10%, Si: 0.80 to 1.50%, Mn: 0.30 to 0.70%, P: 0.030% or less, S: 0.030% or less, Al: 0.010 to 0.070%, N: 0.0010 to 0.010%, Cr: 0 to 0.50%, V: 0 to 0.10%, B: 0 to 0.005%, Ni: 0 to 1.0%, Cu: 0 to 0.50%, and the balance: Fe and impurities. A ratio between the Vickers hardness (HvS) at a location (surface layer) that is 0.1D [D: diameter of steel wire] from the surface of the steel wire and the Vickers hardness (HvI) of a region on the inner side relative to the surface layer satisfies the formula [1.10<HvS/HvI?1.15]. The steel micro-structure in the region from the surface of the steel wire to 0.01D (outermost layer region) consists of, in area %, a pearlite structure: less than 80%, and the balance: a ferrite structure and/or a bainitic structure.
    Type: Grant
    Filed: July 20, 2016
    Date of Patent: August 25, 2020
    Assignees: NIPPON STEEL CORPORATION, SUMITOMO ELECTRIC INDUSTRIES, LTD.
    Inventors: Makoto Okonogi, Daisuke Hirakami, Masato Yamada, Katsuhito Oshima, Shuichi Tanaka
  • Publication number: 20200224288
    Abstract: A predetermined composition is had, when a C content is represented by (C %), in a case of (C %) being not less than 0.35% nor more than 0.65%, a volume fraction of pearlite is 64×(C %)+52% or more, and in a case of (C %) being greater than 0.65% and 0.85% or less, the volume fraction of pearlite is not less than 94% nor more than 100%, and a structure of the other portion is composed of one or two of proeutectoid ferrite and bainite. Further, in a region to a depth of 1.0 mm from a surface, a volume fraction of pearlite block having an aspect ratio of 2.0 or more is not less than 70% nor more than 95%, and a volume fraction of pearlite having an angle between an axial direction and a lamellar direction on a cross section parallel to the axial direction of 40° or less is 60% or more with respect to all pearlite.
    Type: Application
    Filed: March 27, 2020
    Publication date: July 16, 2020
    Applicant: NIPPON STEEL CORPORATION
    Inventors: Makoto OKONOGI, Shingo YAMASAKI, Akifumi KAWANA, Hideaki GOTOHDA
  • Patent number: 10704118
    Abstract: A predetermined composition is had, when a C content is represented by (C %), in a case of (C %) being not less than 0.35% nor more than 0.65%, a volume fraction of pearlite is 64×(C %)+52% or more, and in a case of (C %) being greater than 0.65% and 0.85% or less, the volume fraction of pearlite is not less than 94% nor more than 100%, and a structure of the other portion is composed of one or two of proeutectoid ferrite and bainite. Further, in a region to a depth of 1.0 mm from a surface, a volume fraction of pearlite block having an aspect ratio of 2.0 or more is not less than 70% nor more than 95%, and a volume fraction of pearlite having an angle between an axial direction and a lamellar direction on a cross section parallel to the axial direction of 40° or less is 60% or more with respect to all pearlite.
    Type: Grant
    Filed: August 11, 2011
    Date of Patent: July 7, 2020
    Assignee: NIPPON STEEL CORPORATION
    Inventors: Makoto Okonogi, Shingo Yamasaki, Akifumi Kawana, Hideaki Gotohda
  • Publication number: 20200123625
    Abstract: Steel wire rod etc. enabling elimination the heat treatment processes of spheroidizing annealing and of quenching and tempering are provided. A predetermined chemical composition is provided, 90% or more of the microstructure by area ratio is bainite, the mean bainite block size of the surface layer measured at the cross-section is 15 ?m or less, the ratio of the mean bainite block size of the surface layer measured at the cross-section and the mean bainite block size measured at the center part is less than 1.0, and the mean particle size of cementite dispersed in bainite is 0.1 ?m or less.
    Type: Application
    Filed: July 5, 2017
    Publication date: April 23, 2020
    Applicant: NIPPON STEEL & SUMITOMO METAL CORPORATION
    Inventors: Makoto OKONOGI, Naoki MATSUI
  • Patent number: 10533242
    Abstract: A steel contains, in a chemical composition, C, Si, Mn, and Al, and contains pearlite as a metallographic structure, and a value obtained by dividing an Mn content in a cementite in the pearlite in terms of at % by an Mn content in a ferrite in the pearlite in terms of at % is higher than 0 and equal to or lower than 5.0.
    Type: Grant
    Filed: June 13, 2014
    Date of Patent: January 14, 2020
    Assignee: NIPPON STEEL CORPORATION
    Inventors: Takahiko Kohtake, Kazuto Kawakami, Makoto Okonogi
  • Patent number: 10487379
    Abstract: Provided is a high-carbon steel wire rod with excellent wire drawability, containing predetermined chemical components and the balance: Fe and impurities. In a cross-section perpendicular to a longitudinal direction, an area fraction of pearlite is equal to or more than 95% and equal to or less than 100%, an average block size of the pearlite is 10 ?m to 30 ?m and standard deviation of block size is 20 ?m or less, and when Ceq.=C (%)+Si (%)/24+Mn (%)/6, a tensile strength is equal to or more than 760×Ceq.+255 MPa and equal to or less than 760×Ceq.+325 MPa, reduction of area in a tensile test is ?65×Ceq.+96(%) or more, and standard deviation of the reduction of area is 6% or less.
    Type: Grant
    Filed: August 3, 2015
    Date of Patent: November 26, 2019
    Assignee: NIPPON STEEL CORPORATION
    Inventors: Makoto Okonogi, Daisuke Hirakami
  • Patent number: 10457998
    Abstract: A steel wire for a non heat-treated mechanical part includes, as a chemical composition, by mass %, a predetermined amount of C, Si, Mn, Cr, Mo, Ti, Al, B, Nb, and V, and limited P, S, N, and O and a remainder of Fe and impurities; in which a structure includes, by volume %, a bainite of greater than or equal to 75×[C %]+25, and a remainder of one or more of a ferrite and a pearlite when an amount of C is set to [C %] by mass %; when an average aspect ratio of a bainite block in a second surface layer area of the steel wire is set as R1, the R1 is greater than or equal to 1.2; when an average grain size of a bainite block in a third surface layer area of the steel wire is set to PS3 ?m, and an average grain size of a bainite block in a third center portion of the steel wire is set to PC3 ?m, the PS3 satisfies Expression (c), and the PS3 and the PC3 satisfy Expression (d), a standard deviation of a grain size of the bainite block in the structure is less than or equal to 8.
    Type: Grant
    Filed: January 27, 2016
    Date of Patent: October 29, 2019
    Assignee: NIPPON STEEL CORPORATION
    Inventors: Makoto Okonogi, Daisuke Hirakami, Tatsusei Tada
  • Patent number: 10435765
    Abstract: A wire rod for a steel cord has a wire diameter R of 3.5 mm to 8.0 mm, and includes, in a chemical composition, by mass %: C: 0.70% to 1.20%; Si: 0.15% to 0.60%; Mn: 0.10% to 1.00%; N: 0.0010% to 0.0050%; Al: more than 0% and 0.0100% or less; and a remainder of Fe and impurities, in which a surface part and a central part are included, a thickness of the surface part is 50 ?m to 0.20×R, the central part includes a pearlite structure in a proportion of 95% to 100% by area %, a C content of the surface part is 40% to 95% of a C content of the central part, and a ratio of a thickness of a lamellar cementite at a center of the thickness of the surface part to a thickness of a lamellar cementite in the central part is 95% or less, whereby high strength and workability can be achieved even after a finish drawing process and cracking or the like caused by a delamination phenomenon can be prevented.
    Type: Grant
    Filed: April 23, 2015
    Date of Patent: October 8, 2019
    Assignee: NIPPON STEEL CORPORATION
    Inventors: Daisuke Hirakami, Makoto Okonogi
  • Patent number: 10287658
    Abstract: A wire material used for manufacturing a non-heat treated component whose tensile strength is 900 MPa to 1300 MPa, containing, in mass %: C: 0.20% to 0.50%, Si: 0.05% to 2.0%, Mn: 0.20% to 1.0%, being limited to contain P: 0.030% or less, S: 0.030% or less, N: 0.005% or less, F1 defined by the following expression (1) is less than 0.60, with the balance made up of Fe and inevitable impurities, wherein a metal structure contains a pearlite structure of 64×(C %)+52% or more in a volume fraction, with the balance made up of one kind or two kinds of a pro-eutectoid ferrite structure and a bainite structure, an average block grain diameter of the pearlite structure at a region from a surface layer to 0.1 D is 15 ?m or less when a diameter of the wire material is set to be D, and (the average block grain diameter of the pearlite structure at the region from the surface layer to 0.1 D)/(an average block grain diameter of the pearlite structure at a range from 0.25 D to a center) is less than 1.0.
    Type: Grant
    Filed: August 23, 2012
    Date of Patent: May 14, 2019
    Assignee: NIPPON STEEL AND SUMITOMO METAL CORPORATION
    Inventors: Makoto Okonogi, Shingo Yamasaki, Akifumi Kawana, Hideaki Gotohda
  • Publication number: 20190024222
    Abstract: A steel wire for non-heat treated machine parts, the steel wire contains, based on % by mass: C: from 0.20 to 0.40%, Si: from 0.05 to 0.50%, Mn: from 0.50 to 2.00%, Al: from 0.005 to 0.050%, and the balance being Fe and impurities, in which the microstructure contains bainite of (35×[C %]+50)% or more, and when the diameter is defined as D, the average aspect ratio of a bainite grain at a depth of 50 ?m in the L cross section is defined as AR, and the average grain size of a bainite grain at a depth of 50 ?M in the C cross section is defined as GD, AR is 1.4 or more, (AR)/(the average aspect ratio of a bainite grain at a depth of 0.25D in the L cross section) is 1.1 or more, GD is (15/AR) ?m or less, and (GD)/(the average grain size of a bainite grain at a depth of 0.25D in the C cross section) is less than 1.0.
    Type: Application
    Filed: January 16, 2017
    Publication date: January 24, 2019
    Applicant: NIPPON STEEL & SUMITOMO METAL CORPORATION
    Inventors: Makoto OKONOGI, Daisuke HIRAKAMI, Naoki MATSUI
  • Patent number: 10174399
    Abstract: A steel wire rod includes required amounts of chemical components and a remainder including Fe and impurities; in which the area ratio of pearlite in a cross section perpendicular to a longitudinal direction is 95% or more and a remainder includes a non-pearlite structure which includes one or more of a bainite, a degenerate pearlite, a proeutectoid ferrite and a proeutectoid cementite; the average block size of the pearlite is 15 ?m to 35 ?m and the area ratio of the pearlite having a block size of 50 ?m or more is 20% or less; and the area ratio of a region where a lamellar spacing of the pearlite is 150 nm or less is 20% or less in a region within a depth from a surface of the steel wire rod of 1 mm or less.
    Type: Grant
    Filed: June 23, 2014
    Date of Patent: January 8, 2019
    Assignee: NIPPON STEEL & SUMITOMO METAL CORPORATION
    Inventors: Makoto Okonogi, Daisuke Hirakami
  • Patent number: 10156001
    Abstract: A filament for a high strength steel cord has a wire diameter R of 0.1 mm to 0.4 mm, and includes, in a chemical composition, by mass %: C: 0.70% to 1.20%; Si: 0.15% to 0.60%; Mn: 0.10% to 1.00%; N: 0.0010% to 0.0050%; Al: more than 0% and 0.0100% or less; and a remainder of Fe and impurities, in which a surface part and a central part are included, a thickness of the surface part is 0.01×R to 0.10×R, the central part includes a pearlite structure in a proportion of 95% to 100% by area %, a C content of the surface part is 40% to 95% of a C content of the central part, and a ratio of a thickness of a lamellar cementite at a center of the thickness of the surface part to a thickness of a lamellar cementite in the central part is 95% or less, whereby high strength and workability can be achieved and cracking or the like caused by a delamination phenomenon can be prevented.
    Type: Grant
    Filed: April 23, 2015
    Date of Patent: December 18, 2018
    Assignee: NIPPON STEEL & SUMITOMO METAL CORPORATION
    Inventors: Daisuke Hirakami, Makoto Okonogi
  • Patent number: 10081846
    Abstract: A steel wire according to an aspect of the present invention includes a predetermined chemical composition, in which a wire diameter R of the steel wire is 1.0 mm to 3.5 mm, a soft portion is formed along an outer circumference of the steel wire, the Vickers hardness of the soft portion is lower than that of a position of the steel wire at a depth of ¼ of the wire diameter R by Hv 30 or higher, the thickness of the soft portion is 5 ?m to 0.1×R mm, the metallographic structure of a center portion of the steel wire contains 95% to 100% of pearlite by area %, the average lamellar spacing of pearlite in a portion from a surface of the steel wire to a depth of 5 ?m is less than that of pearlite at the center of the steel wire, the difference between the average lamellar spacing of pearlite in the portion from the surface of the steel wire to the depth of 5 ?m and the average lamellar spacing of pearlite at the center of the steel wire is 3 nm to 60 nm, and the tensile strength is 1100 MPa or higher.
    Type: Grant
    Filed: February 6, 2015
    Date of Patent: September 25, 2018
    Assignee: NIPPON STEEL & SUMITOMO METAL CORPORATION
    Inventors: Daisuke Hirakami, Makoto Okonogi
  • Patent number: 10072317
    Abstract: A filament according to an aspect of the present invention includes a predetermined chemical composition, in which a diameter r of the filament is 0.15 mm to 0.35 mm, a soft portion is formed along an outer circumference of the filament, the Vickers hardness of the soft portion is lower than that of a position of the filament at a depth of ¼ of the diameter r by Hv 50 or higher, the thickness of the soft portion is 1 ?m to 0.1×r mm, the metallographic structure of a center portion of the filament contains 95% to 100% of pearlite by area %, the average lamellar spacing of pearlite in a portion from a surface of the filament to a depth of 1 ?m is less than that of pearlite at the center of the filament, the difference between the average lamellar spacing of pearlite in the portion from the surface of the filament to the depth of 1 ?m and the average lamellar spacing of pearlite at the center of the filament is 2.0 nm or less, and the tensile strength is 3200 MPa or higher.
    Type: Grant
    Filed: February 6, 2015
    Date of Patent: September 11, 2018
    Assignee: NIPPON STEEL & SUMITOMO METAL CORPORATION
    Inventors: Daisuke Hirakami, Makoto Okonogi
  • Publication number: 20180216213
    Abstract: This invention provides a high-strength PC steel wire having a chemical composition containing, in mass %, C: 0.90 to 1.10%, Si: 0.80 to 1.50%, Mn: 0.30 to 0.70%, P: 0.030% or less, S: 0.030% or less, Al: 0.010 to 0.070%, N: 0.0010 to 0.010%, Cr: 0 to 0.50%, V: 0 to 0.10%, B: 0 to 0.005%, Ni: 0 to 1.0%, Cu: 0 to 0.50%, and the balance: Fe and impurities. A ratio between the Vickers hardness (HvS) at a location (surface layer) that is 0.1D [D: diameter of steel wire] from the surface of the steel wire and the Vickers hardness (HvI) of a region on the inner side relative to the surface layer satisfies the formula [1.10<HvS/HvI?1.15]. An average carbon concentration in a region from the surface to a depth of 10 ?m (outermost layer region) of the steel wire is 0.8 times or less a carbon concentration of the steel wire. The steel micro-structure in the region on the inner side relative to the outermost layer region contains, in area %, a pearlite structure: 95% or more.
    Type: Application
    Filed: July 20, 2016
    Publication date: August 2, 2018
    Inventors: Makoto OKONOGI, Daisuke HIRAKAMI, Masato YAMADA, Katsuhito OSHIMA, Shuichi TANAKA
  • Publication number: 20180216208
    Abstract: This invention provides a high-strength PC steel wire having a chemical composition containing, in mass %, C: 0.90 to 1.10%, Si: 0.80 to 1.50%, Mn: 0.30 to 0.70%, P: 0.030% or less, S: 0.030% or less, Al: 0.010 to 0.070%, N: 0.0010 to 0.010%, Cr: 0 to 0.50%, V: 0 to 0.10%, B: 0 to 0.005%, Ni: 0 to 1.0%, Cu: 0 to 0.50%, and the balance: Fe and impurities. A ratio between the Vickers hardness (HvS) at a location (surface layer) that is 0.1D [D: diameter of steel wire] from the surface of the steel wire and the Vickers hardness (HvI) of a region on the inner side relative to the surface layer satisfies the formula [1.10<HvS/HvI?1.15]. The steel micro-structure in the region from the surface of the steel wire to 0.01D (outermost layer region) consists of, in area %, a pearlite structure: less than 80%, and the balance: a ferrite structure and/or a bainitic structure.
    Type: Application
    Filed: July 20, 2016
    Publication date: August 2, 2018
    Inventors: Makoto OKONOGI, Daisuke HIRAKAMI, Masato YAMADA, Katsuhito OSHIMA, Shuichi TANAKA