Patents by Inventor Kunio Hayashi

Kunio Hayashi 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: 20210040588
    Abstract: A steel sheet has a predetermined chemical composition and a metal structure represented by, in area fraction, polygonal ferrite: 40% or less, martensite: 20% or less, bainitic ferrite: 50% to 95%, and retained austenite: 5% to 50%. In area fraction, 80% or more of the bainitic ferrite is composed of bainitic ferrite grains that have an aspect ratio of 0.1 to 1.0 and have a dislocation density of 8×102 (cm/cm3) or less in a region surrounded by a grain boundary with a misorientation angle of 15° or more. In area fraction, 80% or more of the retained austenite is composed of retained austenite grains that have an aspect ratio of 0.1 to 1.0, have a major axis length of 1.0 ?m to 28.0 ?m, and have a minor axis length of 0.1 ?m to 2.8 ?m.
    Type: Application
    Filed: March 30, 2018
    Publication date: February 11, 2021
    Applicant: NIPPON STEEL CORPORATION
    Inventors: Yuri TODA, Eisaku SAKURADA, Kunio HAYASHI, Akihiro UENISHI
  • Patent number: 10907235
    Abstract: A steel sheet according to an aspect of the present invention has a chemical composition within a predetermined range; in which a metallographic structure at a thickness ¼ portion includes, by unit area %, ferrite: 10% or more and less than 50%, granular bainite: 5% or more and less than 50%, and martensite: 20% or more and less than 60%; in the metallographic structure at the thickness ¼ portion, a total of upper bainite, lower bainite, residual austenite, and pearlite is 0% or more and less than 15% by unit area %; at the thickness ¼ portion, a product of an area ratio Vm of the martensite and an average hardness Hv of the martensite is 12,000 to 34,000; and a tensile strength is 980 MPa or higher.
    Type: Grant
    Filed: September 13, 2016
    Date of Patent: February 2, 2021
    Assignee: NIPPON STEEL CORPORATION
    Inventors: Yuri Toda, Kunio Hayashi, Katsuya Nakano, Hiroyuki Kawata, Akihiro Uenishi
  • Publication number: 20210017622
    Abstract: A hot dip galvanized steel sheet and hot dip galvannealed steel sheet improved in uniform ductility and local ductility, yield strength and tensile strength, and low temperature impact property, characterized by having a predetermined chemical composition, having a metal structure containing, by volume %, retained austenite: over 5.0% and tempered martensite: over 5.0%, having retained austenite containing C: 0.85 mass % or more, and having a ratio [C]?gb/[P]?gb of an amount of segregation of C (number of atoms/nm2): [C]?gb to an amount of segregation of P (number of atoms/nm2): [P]?gb at prior austenite grain boundaries of 4.0 or more.
    Type: Application
    Filed: March 30, 2018
    Publication date: January 21, 2021
    Applicant: NIPPON STEEL CORPORATION
    Inventors: Jun HAGA, Kohichi SANO, Koutarou HAYASHI, Kunio HAYASHI, Masaharu KAMEDA, Akihiro UENISHI, Hiroyuki KAWATA
  • Patent number: 10895002
    Abstract: A steel sheet includes a predetermined chemical composition and a metal structure represented by, in area fraction, ferrite: 30% to 50%, granular bainite: 5% to 20%, martensite: 30% to 55%, bainite: less than 35%, and retained austenite and pearlite: 10% or less in total. Preferably, of the steel sheet, a tensile strength is 1180 MPa or more, elongation is 10% or more, and a hole expansion value is 20% or more. Further preferably, a VDA bending angle in the case where a thickness is set to t (mm) is “7.69t2?38.4t+109” or more.
    Type: Grant
    Filed: January 30, 2017
    Date of Patent: January 19, 2021
    Assignee: NIPPON STEEL CORPORATION
    Inventors: Katsuya Nakano, Kunio Hayashi, Yuri Toda, Eisaku Sakurada, Akihiro Uenishi
  • Patent number: 10876181
    Abstract: In a cold-rolled steel sheet having a predetermined chemical composition, a metallographic structure contains 40.0% or more and less than 60.0% of a polygonal ferrite, 30.0% or more of a bainitic ferrite, 10.0% to 25.0% of a residual austenite, and 15.0% or less of a martensite, by an area ratio, in the residual austenite, a proportion of the residual austenite in which an aspect ratio is 2.0 or less, a length of a long axis is 1.0 ?m or less, and a length of a short axis is 1.0 ?m or less, is 80.0% or more, in the bainitic ferrite, a proportion of the bainitic ferrite in which an aspect ratio is 1.7 or less and an average value of a crystal orientation difference in a region surrounded by a boundary in which a crystal orientation difference is 15° or more is 0.5° or more and less than 3.0°, is 80.0% or more, and a connection index D value of the martensite, the bainitic ferrite, and the residual austenite is 0.70 or less.
    Type: Grant
    Filed: February 24, 2016
    Date of Patent: December 29, 2020
    Assignee: NIPPON STEEL CORPORATION
    Inventors: Kengo Takeda, Kunio Hayashi, Akihiro Uenishi, Masafumi Azuma, Takayuki Nozaki, Yuri Toda
  • Publication number: 20200325554
    Abstract: A steel sheet having a chemical composition of the base metal including, in mass %, C: 0.17 to 0.40%, Si: 0.10 to 2.50%, Mn: 1.00 to 10.00%, P: 0.001 to 0.03%, S: 0.0001 to 0.02%, Al: 0.001 to 2.50%, N: 0.0001 to 0.010%, O: 0.0001 to 0.010%, Ti: 0 to 0.10%, Nb: 0 to 0.10%, V: 0 to 0.10%, B: 0 to 0.010%, Cr: 0 to 2.00%, Ni: 0 to 2.00%, Cu: 0 to 2.00%, Mo: 0 to 2.00%, Ca: 0 to 0.50%, Mg: 0 to 0.50%, REM: 0 to 0.50%, the balance: Fe and impurities, wherein the steel sheet has an internal oxidized layer in which at least one part of a crystal grain boundary is covered by oxides, and in which a grain boundary coverage ratio of oxides is 60% or more in a region from the surface of the base metal to a depth of 5.0 ?m.
    Type: Application
    Filed: December 15, 2017
    Publication date: October 15, 2020
    Applicant: NIPPON STEEL CORPORATION
    Inventors: Kengo TAKEDA, Kunio HAYASHI, Akihiro UENISHI, Hiroyuki KAWATA, Chisato YOSHINAGA, Yasunobu MIYAZAKI, Toyomitsu NAKAMURA
  • Patent number: 10787727
    Abstract: A steel sheet includes a predetermined chemical composition, and includes a steel structure represented by, in a volume fraction, tempered martensite and bainite: 70% or more and less than 92% in total, retained austenite: 8% or more and less than 30%, ferrite: less than 10%, fresh martensite: less than 10%, and pearlite: less than 10%. A number density of iron-base carbides in tempered martensite and lower bainite is 1.0×106 (pieces/mm2) or more, and an effective crystal grain diameter of tempered martensite and bainite is 5 ?m or less.
    Type: Grant
    Filed: September 21, 2016
    Date of Patent: September 29, 2020
    Assignee: NIPPON STEEL CORPORATION
    Inventors: Kunio Hayashi, Masafumi Azuma
  • Publication number: 20200283869
    Abstract: A high-strength cold-rolled steel sheet which is a steel sheet having a tensile strength of 980 MPa or more has a predetermined chemical component composition, a metallographic microstructure of the steel sheet contains, by area ratio, ferrite and granular bainite: 10% or more and 50% or less in total, one or both of upper bainite and lower bainite: 10% or more and 50% or less in total, tempered martensite: more than 0% and 30% or less, retained austenite: 5% or more, and one or more of pearlite, cementite, and martensite: 0% to 10% in total, and an area ratio of the ferrite with respect to a total area ratio of the ferrite and the granular bainite is 25% or less.
    Type: Application
    Filed: November 15, 2017
    Publication date: September 10, 2020
    Applicant: NIPPON STEEL CORPORATION
    Inventors: Yuri TODA, Kunio HAYASHI, Katsuya NAKANO, Eisaku SAKURADA, Akihiro UENISHI, Kengo TAKEDA
  • Patent number: 10758199
    Abstract: In an X-ray diagnostic apparatus according to an embodiment, an X-ray generator configured to irradiate an X-ray to a subject. An X-ray detector configured to detect the X-ray. Processing circuitry configured to generate a plurality of X-ray images chronologically based on X-rays that have passed through the subject to which a contrast media is injected, and that have been detected by the X-ray detector. The processing circuitry configured to extract a first image from among the X-ray images, the first image when any one of a change in a pixel value between predetermined two images and a predetermined region in one image is equal to or smaller than a threshold. A display configured to display, after the first image is extracted, a plurality of X-ray images that have been generated prior to the first image in reverse chronological order.
    Type: Grant
    Filed: August 27, 2015
    Date of Patent: September 1, 2020
    Assignee: Canon Medical Systems Corporation
    Inventors: Yoshiyasu Hayashi, Nobuo Kobayashi, Kunio Shiraishi
  • Publication number: 20200232060
    Abstract: High strength steel sheet having a tensile strength of 800 MPa or more comprising a middle part in sheet thickness and a soft surface layer arranged at one side or both sides of the middle part in sheet thickness, wherein each soft surface layer has a thickness of more than 10 ?m and 30% or less of the sheet thickness, the soft surface layer has an average Vickers hardness of 0.60 time or less the average Vickers hardness of the sheet thickness ½ position, and the soft surface layer has a nano-hardness standard deviation of 0.8 or less is provided.
    Type: Application
    Filed: February 20, 2018
    Publication date: July 23, 2020
    Applicant: NIPPON STEEL CORPORATION
    Inventors: Katsuya NAKANO, Yuya SUZUKI, Genki ABUKAWA, Kunio HAYASHI
  • Patent number: 10718044
    Abstract: A hot-dip galvanized steel sheet includes: a predetermined chemical composition; and a steel structure represented by: in terms of area ratio, polygonal ferrite: 10% or less; upper bainite: 20% or less; retained austenite: 5% or less; and martensite: 70% or more, in which: martensite having Fe carbides at a number density of 1×106/mm2 or more is contained by 50% or more, in terms of area ratio, with respect to the entire amount of martensite; and the steel structure has an average effective crystal grain diameter of 5.0 ?m or less.
    Type: Grant
    Filed: July 15, 2016
    Date of Patent: July 21, 2020
    Assignee: NIPPON STEEL CORPORATION
    Inventors: Takafumi Yokoyama, Kunio Hayashi, Masafumi Azuma, Eisaku Sakurada, Hiroyuki Kawata, Genki Abukawa
  • Publication number: 20200157666
    Abstract: A hot press-formed part according to an aspect of the present invention contains a predetermined chemical composition; in which a microstructure in a thickness ¼ portion includes, by unit vol %, tempered martensite: 20% to 90%, bainite: 5% to 75%, and residual austenite: 5% to 25%, and ferrite is limited to 10% or less; and a pole density of an orientation {211}<011> in the thickness ¼ portion is 3.0 or higher.
    Type: Application
    Filed: August 16, 2016
    Publication date: May 21, 2020
    Applicant: NIPPON STEEL & SUMITOMO METAL CORPORATION
    Inventors: Mutsumi SAKAKIBARA, Natsuko SUGIURA, Kunio HAYASHI, Kaoru KAWASAKI
  • Publication number: 20200115771
    Abstract: A high-strength hot-dip galvanized steel sheet contains predetermined amounts of C, Si, Mn, P, S, N, O, sol. Al, Ti, and B, 0.1 to 1.5 mass % of Cr+2×Mo, and a balance in a form of Fe and inevitable impurities. A steel structure includes, in area %, ferrite: 1 to 50%, martensite: 20 to 70%, residual austenite: 0 to 5%, pearlite: 0 to 5%, MA and cementite having 0.2 ?m or more grain size: 0 to 5% in total, and a balance in a form of bainite. A number density of MA or cementite having 0.2 ?m or more grain size and isolated in ferrite or bainite grains is 100 pcs/1000 ?m2 or less, and an average hardness of martensite is in a range from 330 to 500 Hv.
    Type: Application
    Filed: March 22, 2018
    Publication date: April 16, 2020
    Applicant: NIPPON STEEL CORPORATION
    Inventors: Takafumi YOKOYAMA, Yuji YAMAGUCHI, Masahiro NAKATA, Kunio HAYASHI, Satoshi UCHIDA, Takuma KAWANAKA
  • Publication number: 20200094525
    Abstract: A steel sheet for hot stamping includes a steel structure represented by an area fraction of bainite, fresh martensite and tempered martensite: 80% or more in total, and a product of a number density (pieces/?m2) of carbides and a proportion of carbides precipitated into prior austenite grains in carbides: 0.50 or more.
    Type: Application
    Filed: January 17, 2017
    Publication date: March 26, 2020
    Applicant: NIPPON STEEL CORPORATION
    Inventors: Genki ABUKAWA, Kunio HAYASHI, Kazuo HIKIDA, Kaoru KAWASAKI
  • Publication number: 20200040435
    Abstract: A steel sheet includes a predetermined chemical composition and a metal structure represented by, in area fraction, ferrite: 50% to 95%, granular bainite: 5% to 48%, martensite: 2% to 30%, and upper bainite, lower bainite, tempered martensite, retained austenite, and pearlite: 5% or less in total.
    Type: Application
    Filed: January 25, 2017
    Publication date: February 6, 2020
    Applicant: NIPPON STEEL & SUMITOMO METAL CORPORATION
    Inventors: Katsuya NAKANO, Kunio HAYASHI, Yuri TODA, Eisaku SAKURADA, Akihiro UENISHI
  • Publication number: 20200024706
    Abstract: A steel sheet includes a predetermined chemical composition and a metal structure represented by, in area fraction, ferrite: 30% to 50%, granular bainite: 5% to 20%, martensite: 30% to 55%, bainite: less than 35%, and retained austenite and pearlite: 10% or less in total. Preferably, of the steel sheet, a tensile strength is 1180 MPa or more, elongation is 10% or more, and a hole expansion value is 20% or more. Further preferably, a VDA bending angle in the case where a thickness is set to t (mm) is “7.69t2?38.4t+109” or more.
    Type: Application
    Filed: January 30, 2017
    Publication date: January 23, 2020
    Applicant: NIPPON STEEL & SUMITOMO METAL CORPORATION
    Inventors: Katsuya NAKANO, Kunio HAYASHI, Yuri TODA, Eisaku SAKURADA, Akihiro UENISHI
  • Publication number: 20200010919
    Abstract: High strength steel sheet having a tensile strength of 800 MPa or more comprising a middle part in sheet thickness and a soft surface layer arranged at one side or both sides of the middle part in sheet thickness, wherein each soft surface layer has a thickness of more than 10 ?M and 30% or less of the sheet thickness, the soft surface layer has an average Vickers hardness of more than 0.60 time and 0.90 time or less the average Vickers hardness of the sheet thickness 1/2 position, and the soft surface layer has a nano-hardness standard deviation of 0.8 or less is provided.
    Type: Application
    Filed: February 20, 2018
    Publication date: January 9, 2020
    Applicant: NIPPON STEEL CORPORATION
    Inventors: Yuya SUZUKI, Katsuya NAKANO, Genki ABUKAWA, Kunio HAYASHI
  • Patent number: 10501832
    Abstract: A base material (13) included in a plated steel sheet (1) includes a structure, at a ¼ sheet thickness position, represented by, in volume fraction: tempered martensite: 3.0% or more; ferrite: 4.0% or more; and retained austenite: 5.0% or more. An average hardness of the tempered martensite in the base material (13) is 5 GPa to 10 GPa, and a part or all of the tempered martensite and the retained austenite in the base material form an M-A. A volume fraction of ferrite in a decarburized ferrite layer (12) included in the plated steel sheet (1) is 120% or more of the volume fraction of the ferrite in the base material (13) at the ¼ sheet thickness position, an average grain diameter of the ferrite in the decarburized ferrite layer (12) is 20 ?m or less, a thickness of the decarburized ferrite layer (12) is 5 ?m to 200 ?m, a volume fraction of tempered martensite in the decarburized ferrite layer (12) is 1.0 volume% or more, a number density of the tempered martensite in the decarburized ferrite layer (12) is 0.
    Type: Grant
    Filed: April 22, 2016
    Date of Patent: December 10, 2019
    Assignee: NIPPON STEEL CORPORATION
    Inventors: Koutarou Hayashi, Akihiro Uenishi, Masaharu Kameda, Jun Haga, Kunio Hayashi, Kohichi Sano, Hiroyuki Kawata
  • Publication number: 20190330721
    Abstract: A steel sheet includes a predetermined chemical composition, and includes a steel structure represented by, in a volume fraction, tempered martensite and bainite: 70% or more and less than 92% in total, retained austenite: 8% or more and less than 30%, ferrite: less than 10%, fresh martensite: less than 10%, and pearlite: less than 10%. A number density of iron-base carbides in tempered martensite and lower bainite is 1.0×106 (pieces/mm2) or more, and an effective crystal grain diameter of tempered martensite and bainite is 5 ?m or less.
    Type: Application
    Filed: September 21, 2016
    Publication date: October 31, 2019
    Applicant: NIPPON STEEL & SUMITOMO METAL CORPORATION
    Inventors: Kunio HAYASHI, Masafumi AZUMA
  • Publication number: 20190330711
    Abstract: A blank material is formed from a steel sheet, a first quenching of the blank material is performed, and a second quenching of the blank material is performed after the first quenching. When the first quenching is performed, the blank material is heated to a first temperature of not lower than (Ac3 point—50)° C. nor higher than 1200° C. at an average heating rate of 2° C./sec or more, and the blank material is cooled from the first temperature to a second temperature of 250° C. or lower. When the second quenching is performed, the blank material is heated from the second temperature to a third temperature of not lower than (Ac3 point—50)° C. nor higher than 1200° C. at an average heating rate of 2° C./sec or more, and the blank material is cooled from the third temperature to a fourth temperature of 250° C. or lower. Forming of the blank material is performed in the first quenching or the second quenching or both of the above.
    Type: Application
    Filed: January 17, 2017
    Publication date: October 31, 2019
    Applicant: NIPPON STEEL & SUMITOMO METAL CORPORATION
    Inventors: Genki ABUKAWA, Kunio HAYASHI, Kazuo HIKIDA, Kaoru KAWASAKI