Patents by Inventor Masafumi Azuma

Masafumi Azuma 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: 20250146094
    Abstract: This cold-rolled steel sheet has a predetermined chemical composition, in which a metallographic structure at a ¼ depth position, which is a ¼ thickness position from a surface, contains, by volume percentage, retained austenite: more than 1.0% and less than 8.0%, tempered martensite: 80.0% or more, ferrite and bainite: 0% or more and 15.0% or less in total, and martensite: 0% or more and 5.0% or less, and in the metallographic structure, a prior ? grain size is 5.0 ?m or more and 25.0 ?m or less, and a number density of retained ? on a prior ? grain boundary is 100/mm2 or less.
    Type: Application
    Filed: December 23, 2022
    Publication date: May 8, 2025
    Applicant: NIPPON STEEL CORPORATION
    Inventors: Takuya NISHIO, Masafumi AZUMA, Ryosuke NAKAMURA
  • Publication number: 20250144737
    Abstract: A method for manufacturing a projection weld joint according to an aspect of the present invention includes: a first energizing step of energizing a steel sheet and a steel member so as to form a plurality of joint portions by projection welding a steel member to a first surface of a steel sheet that is a non-coated steel sheet or a zinc-type-coated steel sheet, in which the steel sheet has a tensile strength of 1.5 GPa or more, and the steel sheet has a Ceq of 0.30 mass % or more, and the manufacturing method further includes: a cooling step of quenching each of the plurality of joint portions; and a second energizing step of further energizing the steel sheet and the steel member so as to temper an end region in each of the plurality of joint portions.
    Type: Application
    Filed: December 23, 2022
    Publication date: May 8, 2025
    Inventors: Masanori YASUYAMA, Masafumi AZUMA, Gen MURAYAMA, Takashi IMAMURA, Masatoshi TOKUNAGA, Koichi OI, Yoshinori OYAMA, Osamu KAWAGUCHI
  • Publication number: 20250066887
    Abstract: This steel sheet for hot-stamping includes: a base steel sheet having a predetermined chemical composition; and a galvanized layer formed on a surface of the base steel sheet, in which a microstructure at a position at ¼ depth which is in a range of ? to ? of a sheet thickness in a sheet thickness direction from the surface of the base steel sheet contains, in volume fraction, ferrite: 20% to 95% and pearlite: 5% to 80%, the remaining structure including bainite, the galvanized layer has a coating amount of 90 g/m2 or more, and when the maximum value of the B content in the galvanized layer is Bps and the B content at the position at ¼ depth of the base steel sheet is Bqs, Bps is 1.2 times or more Bqs.
    Type: Application
    Filed: January 6, 2023
    Publication date: February 27, 2025
    Applicant: NIPPON STEEL CORPORATION
    Inventors: Masafumi AZUMA, Akihiro SENGOKU, Shota KIKUCHI
  • Patent number: 12221661
    Abstract: A steel sheet includes, as a chemical composition, by mass %: C: 0.0015% to 0.0400%; Mn: 0.20% to 1.50%; P: 0.010% to 0.100%; Cr: 0.001% to 0.500%; Si: 0.200% or less; S: 0.020% or less; sol. Al: 0.200% or less; N: 0.0150% or less; Mo: 0% to 0.500%; B: 0% to 0.0100%; Nb: 0% to 0.200%; Ti: 0% to 0.200%; Ni: 0% to 0.200%; Cu: 0% to 0.100%; and a remainder including iron and impurities, in which a metallographic structure in a surface layer region includes ferrite having a volume fraction of 90% or more, and in the surface layer region, an average grain size of the ferrite is 1.0 ?m to 15.0 ?m, and a texture in which an XODF{001}/{111}, S as a ratio of an intensity of {001} orientation to an intensity of {111} orientation in the ferrite is 0.30 or more and less than 3.50 is included.
    Type: Grant
    Filed: January 7, 2020
    Date of Patent: February 11, 2025
    Assignee: NIPPON STEEL CORPORATION
    Inventors: Masahiro Kubo, Hiroyuki Kawata, Kenichiro Otsuka, Masafumi Azuma
  • Patent number: 12215402
    Abstract: This hot-rolled steel sheet has a predetermined chemical composition, a microstructure includes 80% or more of tempered martensite by a volume percentage and a remainder consisting of one or more of ferrite, pearlite, bainite, fresh martensite, and residual austenite, the tempered martensite includes 5×109 pieces/mm3 or more of precipitates containing Ti and having an equivalent circle diameter of 5 nm or less per unit volume, in a surface layer region that is a range from a surface to a 1/10 position of a sheet thickness, a sum of an average pole density of a crystal orientation group consisting of {211}<111> to {111}<112> and a pole density in a crystal orientation of {110}<001> is 6.0 or less, and a tensile strength is 980 MPa or more.
    Type: Grant
    Filed: December 15, 2020
    Date of Patent: February 4, 2025
    Assignee: NIPPON STEEL CORPORATION
    Inventors: Genki Abukawa, Masafumi Azuma, Eisaku Sakurada, Shohei Yabu
  • Patent number: 12209300
    Abstract: An automobile undercarriage part of the present invention has a welded joint formed by base steel plate, wherein the chemical composition of a weld metal contains, with respect to a total mass of the weld metal, by mass %, C: 0.02% to 0.30%, Si: 0.10% to less than 1.0%, Mn: 1.2% to 3.0%, Al: 0.002% to 0.30%, Ti: 0.005% to 0.30%, P: more than 0% to 0.015%, and S: more than 0% to 0.030%, the following formula (1A), formula (1B), formula (2), and formula (3) are satisfied, and slag in a toe portion of the fillet weld satisfies a formula (4). [Al]+[Ti]>0.05??Formula (1A) [Ti]/[Al]>0.9??Formula(1B) 7×[Si]+7×[Mn]?112×[Ti]?30×[Al]?12??Formula (2) 2.0<[Si]+[Mn]??Formula (3) [Ti content on slag surface]>[Si content on slag surface]??Formula (4).
    Type: Grant
    Filed: March 27, 2020
    Date of Patent: January 28, 2025
    Assignee: NIPPON STEEL CORPORATION
    Inventors: Kenichiro Otsuka, Masafumi Azuma, Yoichiro Mori, Shinji Kodama, Masahiro Matsuba
  • Patent number: 12194806
    Abstract: A suspension arm includes a main body. The main body includes a curved portion curved along a longitudinal direction and has a closed section. The main body includes an inner side wall, an outer side wall, a first side wall, and a second side wall. The inner side wall corresponds to an inner side of a curve of the curved portion. The outer side wall corresponds to an outer side of the curve of the curved portion. A thickness of the inner side wall is larger than a thickness of the outer side wall. In sectional view of the main body perpendicular to the longitudinal direction, each of a length of the first side wall and a length of the second side wall is longer than each of a length of the inner side wall and a length of the outer side wall.
    Type: Grant
    Filed: March 28, 2022
    Date of Patent: January 14, 2025
    Assignee: NIPPON STEEL CORPORATION
    Inventors: Kenichiro Otsuka, Masafumi Azuma, Koichi Hamada, Ryo Tabata, Ryo Urushibata, Yuki Kitahara
  • Publication number: 20240417820
    Abstract: This cold-rolled steel sheet has a predetermined chemical composition, in which a metallographic structure of a t/4 portion, which is at a ¼ position of a sheet thickness t from a surface of the cold-rolled steel sheet in a sheet thickness direction, includes, by volume percentage, retained austenite: 2.5% or more and 10.0% or less, tempered martensite: 80.0% or more and 97.5% or less, ferrite and bainite: 0.0% or more and 15.0% or less in total, and martensite: 0.0% or more and 3.0% or less, and in a surface layer area at a position 25 ?m away from the surface in the sheet thickness direction, an amount of solute Si is 0.30% or more and 1.50% or less by mass %, a volume percentage of ferrite in the metallographic structure is 0.0% or more and 20.0% or less, and a density of ferrite grains having a grain size of 15 ?m or more is 0 grains/mm2 or more and 3,000 grains/mm2 or less.
    Type: Application
    Filed: March 1, 2022
    Publication date: December 19, 2024
    Applicant: NIPPON STEEL CORPORATION
    Inventors: Takuya NISHIO, Ryosuke NAKAMURA, Masafumi AZUMA
  • Patent number: 12163209
    Abstract: An automobile undercarriage part of the present invention is an automobile undercarriage part including a welded joint in which a first steel sheet and a second steel sheet are overlapped and a fillet weld is formed between an end surface of the first steel sheet and a surface of the second steel sheet, in which a chemical composition of a weld metal that forms the welded joint contains, with respect to a total mass of the weld metal, by mass %, C: 0.02% to 0.20%, Si: more than 0% to less than 0.10%, Mn: 0.3% to 2.0%, Al: 0.002% to 0.30%. Ti: 0.005% to 0.30%, P: more than 0% to 0.015%, and S: more than 0% to 0.030%, and the following formula (1) and formula (2) are satisfied. [Al]+[Ti]>0.05??Formula (1) 7×[Mn]?112×[Ti]?30×[Al]?4.
    Type: Grant
    Filed: March 27, 2020
    Date of Patent: December 10, 2024
    Assignee: NIPPON STEEL CORPORATION
    Inventors: Kenichiro Otsuka, Masafumi Azuma, Yoichiro Mori, Shinji Kodama, Masahiro Matsuba
  • Patent number: 12123095
    Abstract: This hot-dip galvanized steel sheet includes: a steel sheet; a boundary layer provided on the steel sheet; and a hot-dip galvanized layer provided on the boundary layer, in which the steel sheet has a predetermined chemical composition, in a region between a surface of the steel sheet and a depth of 25 ?m from the surface of the steel sheet, an average grain size exceeds 4.0 ?m, in a region between a position of 50 ?m from the surface of the steel sheet and a position of 100 ?m from the surface of the steel sheet, an area ratio of unrecrystallized ferrite is 50% or more, and in the hot-dip galvanized layer, a maximum value of a C concentration is 0.05 mass % or more.
    Type: Grant
    Filed: July 20, 2021
    Date of Patent: October 22, 2024
    Assignee: NIPPON STEEL CORPORATION
    Inventors: Shota Kikuchi, Masafumi Azuma
  • Publication number: 20240309482
    Abstract: This cold-rolled steel sheet has a predetermined chemical composition, in which a metallographic structure of a t/4 portion, which is at a ¼ position of a sheet thickness t from a surface of the cold-rolled steel sheet in a sheet thickness direction has a predetermined structure, and in both an edge portion, which is at a position 50 mm away from an end portion of the cold-rolled steel sheet in a width direction, and a center portion of the cold-rolled steel sheet in the width direction, a metallographic structure of a 20 ?m portion, which is at a position 20 ?m away from the surface in the sheet thickness direction, includes, by volume percentage, ferrite and bainite: 75.0% or more and 100.0% or less in total, and martensite and tempered martensite: 0.0% or more and 25.0% or less in total, an average grain size of the martensite and the tempered martensite in the metallographic structure of the 20 ?m portion is 5.
    Type: Application
    Filed: March 1, 2022
    Publication date: September 19, 2024
    Applicant: NIPPON STEEL CORPORATION
    Inventors: Takuya NISHIO, Masafumi AZUMA, Yoshimasa NARITA, Shintaro OKURA
  • Patent number: 12018344
    Abstract: A high-strength steel sheet includes a predetermined chemical composition, a microstructure contains, by volume percentage, 80% or more of tempered martensite, and a remainder consists of ferrite and bainite, the microstructure contains 5.0×1011 pieces/mm3 or more of, per unit volume, precipitate containing Ti and having an equivalent circle diameter of 5.0 nm or less, Hvs/Hvc which is a ratio of an average hardness Hvs at a position of a depth of 20 ?m from a surface to an average hardness Hvc at a position of 0.20 to 0.50 mm from the surface is 0.85 or more, and the tensile strength is 1,180 MPa or more.
    Type: Grant
    Filed: March 19, 2020
    Date of Patent: June 25, 2024
    Assignee: NIPPON STEEL CORPORATION
    Inventors: Masafumi Azuma, Eisaku Sakurada, Genki Abukawa, Kenichiro Otsuka, Takeshi Toyoda
  • Patent number: 12005960
    Abstract: An objective of the present disclosure is to provide a front pillar outer that is inexpensive, lightweight and strong. In an area in which a first door-side flange part and a second door-side flange part overlap with each other, a first plate part that is connected to a side edge of the first door-side flange part is folded so that a second door-side flange part is sandwiched between the first door-side flange part and the folded first plate part. In an area in which a first glass-face-side flange part and a second glass-face-side flange part overlap with each other, a second plate part that is connected to a side edge of the first glass-face-side flange part is folded so that the second glass-face-side flange part is sandwiched between the first glass-face-side flange part and the folded second plate part.
    Type: Grant
    Filed: July 14, 2020
    Date of Patent: June 11, 2024
    Assignee: NIPPON STEEL CORPORATION
    Inventors: Kenichiro Otsuka, Masafumi Azuma, Naoki Kimoto
  • Publication number: 20240123782
    Abstract: A suspension arm includes a main body. The main body includes a curved portion curved along a longitudinal direction and has a closed section. The main body includes an inner side wall, an outer side wall, a first side wall, and a second side wall. The inner side wall corresponds to an inner side of a curve of the curved portion. The outer side wall corresponds to an outer side of the curve of the curved portion. A thickness of the inner side wall is larger than a thickness of the outer side wall. In sectional view of the main body perpendicular to the longitudinal direction, each of a length of the first side wall and a length of the second side wall is longer than each of a length of the inner side wall and a length of the outer side wall.
    Type: Application
    Filed: March 28, 2022
    Publication date: April 18, 2024
    Applicant: NIPPON STEEL CORPORATION
    Inventors: Kenichiro OTSUKA, Masafumi AZUMA, Koichi HAMADA, Ryo TABATA, Ryo URUSHIBATA, Yuki KITAHARA
  • Publication number: 20240100583
    Abstract: Provided is a burring processing method, which is a method for forming a buffing processed portion including a raised portion and a curved portion in a metal component having a pilot hole formed therein, the method being characterized by including: a preforming step of enlarging a diameter of the pilot hole, moving an edge portion of the pilot hole relative to the metal component in a first direction of a thickness direction of the metal component in a first range around the pilot hole of the metal component, and forming the whole first range into a preformed portion raised from the metal component in the first direction; and a main forming step of deforming the preformed portion in a second direction opposite to the first direction, forming a second range on an outer diameter side of the preformed portion to have the same height as the first range in the first direction, and forming part of a third range on an inner diameter side of the preformed portion from the second range to be part of the curved portion
    Type: Application
    Filed: January 12, 2022
    Publication date: March 28, 2024
    Applicant: NIPPON STEEL CORPORATION
    Inventors: Kenichiro OTSUKA, Masafumi AZUMA, Koichi HAMADA, Ryo TABATA, Ryo URUSHIBATA, Yuuki KITAHARA
  • Publication number: 20240011113
    Abstract: A steel sheet for hot stamping includes, as a chemical composition, by mass %: C: 0.060% to 0.120%; Si: 0% to 0.70%; Mn: 1.60% to 3.00%; P: 0.100% or less; S: 0.0100% or less; N: 0.0100% or less; Al: 0.001% to 0.100%; Ti: 0.005% to 0.050%; and B: 0.0005% to 0.0100%. If necessary, the chemical composition contains one or two or more selected from the group consisting of Nb, V, W, Ni, Cu, Mo, Sn, Ca, Mg, and REM and a remainder of Fe and impurities, A microstructure includes 70% or more of upper bainite by area ratio, and a number density of iron carbides having a major axis of 0.01 ?m or more included in the upper bainite is equal to or greater than 4/?m2.
    Type: Application
    Filed: October 15, 2021
    Publication date: January 11, 2024
    Applicant: NIPPON STEEL CORPORATION
    Inventors: Masafumi AZUMA, Yuri TODA, Kenichiro OTSUKA
  • Patent number: 11859260
    Abstract: A steel sheet has a predetermined chemical composition, in which a metallographic structure in a surface layer region ranging from a surface to a position of 20 ?m from the surface in a sheet thickness direction consists of ferrite and a secondary phase having a volume fraction of 1.0% to 15.0%, the metallographic structure in an internal region ranging from a position of more than 20 ?m from the surface in the sheet thickness direction to a ¼ thickness position from the surface in the sheet thickness direction consists of ferrite and a secondary phase having a volume fraction of 5.0% to 25.0%, the volume fraction of the secondary phase in the surface layer region is less than the volume fraction of the secondary phase in the internal region, and in the surface layer region, the average grain size of the secondary phase is 0.5 ?m to 4.0 ?m.
    Type: Grant
    Filed: January 7, 2020
    Date of Patent: January 2, 2024
    Assignee: NIPPON STEEL CORPORATION
    Inventors: Masahiro Kubo, Hiroyuki Kawata, Masahiro Saito, Kenichiro Otsuka, Masafumi Azuma
  • Publication number: 20230416856
    Abstract: This steel sheet for gas soft nitriding has a predetermined chemical composition and metallographic structure, in which, when a sheet thickness is indicated as t, a sheet width, which is a width in a direction perpendicular to a rolling direction, is indicated as w, and effective grain sizes are measured at seven positions of w/8, w/4, 3w/8, w/2, 5w/8, 3w/4, and 7w/8 in a width direction from an end portion in the width direction at a t/4 depth position from a surface, an average effective grain size, which is an average of the effective grain sizes at the seven positions, is 8.0 to 35.0 ?m, and an effective grain size difference, which is a difference between a maximum value and a minimum value among the effective grain sizes at the seven positions, is 10.0 ?m or less.
    Type: Application
    Filed: February 18, 2022
    Publication date: December 28, 2023
    Applicant: NIPPON STEEL CORPORATION
    Inventors: Masafumi AZUMA, Shinya SAITOH, Eisaku SAKURADA
  • Publication number: 20230313356
    Abstract: This hot-dip galvanized steel sheet includes: a steel sheet; a boundary layer provided on the steel sheet; and a hot-dip galvanized layer provided on the boundary layer, in which the steel sheet has a predetermined chemical composition, in a region between a surface of the steel sheet and a depth of 25 ?m from the surface of the steel sheet, an average grain size exceeds 4.0 ?m, in a region between a position of 50 ?m from the surface of the steel sheet and a position of 100 ?m from the surface of the steel sheet, an area ratio of unrecrystallized ferrite is 50% or more, and in the hot-dip galvanized layer, a maximum value of a U concentration is 0.05 mass % or more.
    Type: Application
    Filed: July 20, 2021
    Publication date: October 5, 2023
    Applicant: NIPPON STEEL CORPORATION
    Inventors: Shota KIKUCHI, Masafumi AZUMA
  • Publication number: 20230295760
    Abstract: This high-strength steel sheet contains predetermined chemical components, in a range from a surface to 1/10 of a sheet thickness in a sheet thickness direction, an average pole density of an orientation group 1 that is an orientation group expressed by ?1=0° to 90°, ?=50° to 60° and ?2=45° in terms of an Euler angle is 1.5 or less, an average pole density of an orientation group 2 that is an orientation group expressed by ?1=450 to 85°, ?=85° to 90° and ?2=45° in terms of the Euler angle is 1.5 or more, an S value that indicates a degree of randomness of surface properties is 7.5 or less, an E value that indicates a degree of concentration of the surface properties is 0.04 or more, and a tensile strength is 590 MPa or more.
    Type: Application
    Filed: September 10, 2021
    Publication date: September 21, 2023
    Applicant: NIPPON STEEL CORPORATION
    Inventors: Genki ABUKAWA, Hiroyuki TANAKA, Masafumi AZUMA, Kazumasa TSUTSUI