Patents by Inventor Yoshiyasu Kawasaki

Yoshiyasu Kawasaki 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: 20240167127
    Abstract: A high-strength steel sheet is disclosed having a specified chemical composition and a steel microstructure composed of, on an area fraction basis, ferrite: 1% to 40%, fresh martensite: 1% to 20%, bainite and tempered martensite in total: 35% to 90%, and retained austenite: 6% or more, wherein a value obtained by dividing an average Mn content (% by mass) of the retained austenite by an average Mn content (% by mass) of the ferrite is 1.1 or more, and a value obtained by dividing an average C content (% by mass) of retained austenite with an aspect ratio of 2.0 or more by an average C content (% by mass) of the ferrite is 3.0 or more, and a value obtained by dividing a C content of all retained austenite by a C content of a T0 composition is 1.0 or more.
    Type: Application
    Filed: November 12, 2021
    Publication date: May 23, 2024
    Applicant: JFE Steel Corporation
    Inventors: Kazuki Endoh, Yoshiyasu Kawasaki, Yuki Toji
  • Publication number: 20240167128
    Abstract: A high-strength steel sheet is disclosed having a specified chemical composition and a steel microstructure composed of, on an area fraction basis, ferrite: 1% to 40%, fresh martensite: less than 1.0%, bainite and tempered martensite in total: 40% to 90%, and retained austenite: 6% or more, wherein a value obtained by dividing an average Mn content (% by mass) of the retained austenite by an average Mn content (% by mass) of the ferrite is 1.1 or more, and a value obtained by dividing an average C content (% by mass) of retained austenite with an aspect ratio of 2.0 or more by an average C content (% by mass) of the ferrite is 3.0 or more, and a diffusible hydrogen content of steel is 0.3 ppm by mass or less.
    Type: Application
    Filed: November 12, 2021
    Publication date: May 23, 2024
    Applicant: JFE Steel Corporation
    Inventors: Kazuki Endoh, Yoshiyasu Kawasaki, Yuki Toji
  • Publication number: 20240158884
    Abstract: A clad steel plate having tensile strength (TS) of 780 MPa or more, excellent ductility, bendability, collision resistance, and LME resistance. The clad steel plate having a base metal and a cladding metal on front and back surfaces of the base metal, and the chemical composition and microstructure of the base metal and the cladding metal being appropriately controlled so that the average Vickers hardness (HVL) of the cladding metal is 260 or less, the average Vickers hardness (HVL) of the cladding metal divided by the average Vickers hardness (HVB) of the base metal is 0.80 or less, the boundary roughness between the base metal and the cladding metal is 50 ?m or less at the maximum height Ry, and the number of voids at the boundary between the base metal and the cladding metal is controlled to 20 or fewer per 10 mm length of the boundary.
    Type: Application
    Filed: February 28, 2022
    Publication date: May 16, 2024
    Applicant: JFE STEEL CORPORATION
    Inventors: Yoshiyasu KAWASAKI, Yuki TOJI, Tatsuya NAKAGAITO, Shinya YAMAGUCHI, Masayasu UENO, Katsutoshi TAKASHIMA, Tomohiro ONO
  • Publication number: 20240150876
    Abstract: A clad steel plate having tensile strength (TS) of 780 MPa or more, excellent bendability, collision resistance, and LME resistance. The clad steel plate having a base metal and a cladding metal on front and back surfaces of the base metal, and the chemical composition and microstructure of the base metal and the cladding metal being appropriately controlled so that the average Vickers hardness (HVL) of the cladding metal is 260 or less, the average Vickers hardness (HVL) of the cladding metal divided by the average Vickers hardness (HVB) of the base metal is 0.80 or less, the boundary roughness between the base metal and the cladding metal is 50 ?m or less at the maximum height Ry, and the number of voids at the boundary between the base metal and the cladding metal is controlled to 20 or fewer per 10 mm length of the boundary.
    Type: Application
    Filed: February 28, 2022
    Publication date: May 9, 2024
    Applicant: JFE STEEL CORPORATION
    Inventors: Yoshiyasu KAWASAKI, Yuki TOJI, Tatsuya NAKAGAITO, Shinya YAMAGUCHI, Masayasu UENO, Katsutoshi TAKASHIMA, Tomohiro ONO
  • Publication number: 20240143958
    Abstract: The present invention includes: an identification code generation unit that generates, from information of a company code including a first code that uniquely identifies a management target in a part of a company in the part of the company and a second code that identifies the part of the company, an identification code including a history of the management target; a hash processing unit that hashes the identification code generated by the identification code generation unit according to a hash function and converts the hashed identification code into a meaningless code; and a reference code generation unit that generates a reference code unified for the entire company based on the meaningless code converted by the hash processing unit.
    Type: Application
    Filed: February 25, 2022
    Publication date: May 2, 2024
    Inventors: Tomohisa KOHIYAMA, Sadao SATOU, Atsushi SAGARA, Yoshiyasu WATANABE, Hideaki YOKOTA, Kazuaki IKARASHI, Hiroyuki KAWASAKI, Katsunori MAEDA, Keigo FUJIWARA, Kazunobu HISATSUNE
  • Publication number: 20240124964
    Abstract: Provided is a galvanized steel sheet having a TS of 980 MPa or more, high YS, excellent ductility, strain hardenability, and hole expansion formability. A base steel sheet has a defined chemical composition and a steel microstructure as follows: area ratio of ferrite: 65.0% or less (including 0%), area ratio of bainitic ferrite: 5.0% or more and 40.0% or less, area ratio of tempered martensite: 0.5% or more and 80.0% or less, area ratio of retained austenite: 3.0% or more, area ratio of fresh martensite: 20.0% or less (including 0%), SBF+STM+2×SMA: 65.0% or more, SMA1/SMA: 0.80 or less, and SMA2/SMA: 0.20 or more.
    Type: Application
    Filed: March 18, 2022
    Publication date: April 18, 2024
    Applicant: JFE STEEL CORPORATION
    Inventors: Sho HIGUCHI, Yoshiyasu KAWASAKI, Tatsuya NAKAGAITO, Tomomi KANAZAWA, Shunsuke YAMAMOTO
  • Publication number: 20240052449
    Abstract: A high strength steel sheet has a yield-point elongation of 1% or greater and a tensile strength of 980 MPa or greater. The high strength steel sheet has a specific chemical composition and microstructure. A ratio of retained austenite grains adjoining a retained austenite grain having a different crystal orientation to total retained austenite grains is 0.60 or greater, the ferrite has an average grain size of 5.0 ?m or less, and the retained austenite has an average grain size of 2.0 ?m or less. A value obtained by dividing a volume fraction V?a by a volume fraction V?b is 0.40 or greater, where the volume fraction V?a is a volume fraction of retained austenite in a fractured portion of a tensile test specimen after a warm tensile test at 150° C., and the volume fraction V?b is a volume fraction of retained austenite before the warm tensile test at 150° C.
    Type: Application
    Filed: September 25, 2020
    Publication date: February 15, 2024
    Applicant: JFE Steel Corporation
    Inventors: Yoshiyasu Kawasaki, Yuki Toji, Muneka Iwasawa, Takayuki Futatsuka, Kentaro Sato
  • Publication number: 20240052464
    Abstract: A high strength steel sheet has a yield-point elongation of 1.0% or greater and a tensile strength of 980 MPa or greater. The high strength steel sheet has a specific chemical composition and microstructure. The ferrite has an average grain size of 5.0 ?m or less, the retained austenite has an average grain size of 2.0 ?m or less, a value obtained by dividing a Mn content of the retained austenite by a Mn content of steel is 1.50 or greater, 15% or more of all retained austenite grains in the retained austenite have an aspect ratio of 3.0 or greater, and 15% or more of all the retained austenite grains in the retained austenite have an aspect ratio of less than 2.0.
    Type: Application
    Filed: September 25, 2020
    Publication date: February 15, 2024
    Applicant: JFE Steel Corporation
    Inventors: Yoshiyasu Kawasaki, Muneka Iwasawa, Yuki Toji, Yoshimasa Funakawa
  • Publication number: 20240026477
    Abstract: A high-strength galvanized steel sheet is disclosed which has a specified chemical composition, has a steel microstructure including, in terms of area fraction, 35% or more and 80% or less of ferrite, 0.1% or more and less than 5.0% of as-quenched martensite, 3.0% or more and 35% or less of tempered martensite, and 8% or more of retained austenite, in which an average grain diameter of the ferrite is 6 ?m or less, in which an average grain diameter of the retained austenite is 3 ?m or less, in which a value calculated by dividing an average Mn content (mass %) in the retained austenite by an average Mn content (mass %) in the ferrite is 1.5 or more.
    Type: Application
    Filed: January 10, 2020
    Publication date: January 25, 2024
    Applicant: JFE Steel Corporation
    Inventors: Kazuki Endoh, Yoshiyasu Kawasaki, Yuki Toji, Yoshimasa Funakawa, Mai Aoyama
  • Patent number: 11814695
    Abstract: A high-strength galvanized steel sheet and a method for producing the steel sheet. The steel sheet has a composition that includes C: 0.030% to 0.250%, Si: 0.01% to 3.00%, Mn: 2.00% to 10.00%, P: 0.001% to 0.100%, S: 0.0001% to 0.0200%, N: 0.0005% to 0.0100%, Ti: 0.005% to 0.200%, on a mass basis, and Fe and inevitable impurities. Additionally, the steel sheet has concentration of solute Mn at a depth of 5 ?m or less from a surface of the steel sheet that is 1.50% by mass or less, and a value obtained by dividing the average mass percentage of Mn in retained austenite by the average mass percentage of Mn in ferrite is 2.0 or more.
    Type: Grant
    Filed: November 8, 2016
    Date of Patent: November 14, 2023
    Assignee: JFE STEEL CORPORATION
    Inventors: Mai Aoyama, Minoru Tanaka, Yoshitsugu Suzuki, Yoshiyasu Kawasaki, Hideyuki Takahashi
  • Patent number: 11788163
    Abstract: A high-strength steel sheet includes a steel structure with: ferrite being 35% to 80% and tempered martensite being greater than 5% and 20% or less in terms of area fraction; retained austenite being 8% or more in terms of volume fraction; an average grain size of: the ferrite being 6 ?m or less; and the retained austenite being 3 ?m or less; a value obtained by dividing an area fraction of blocky austenite by a sum of area fractions of lath-like austenite and the blocky austenite being 0.6 or more; a value obtained by dividing, by mass %, an average Mn content in the retained austenite by an average Mn content in the ferrite being 1.5 or more; and a value obtained by dividing, by mass %, an average C content in the retained austenite by an average C content in the ferrite being 3.0 or more.
    Type: Grant
    Filed: March 20, 2019
    Date of Patent: October 17, 2023
    Assignee: JFE STEEL CORPORATION
    Inventors: Kazuki Endo, Yoshiyasu Kawasaki, Yuki Toji, Yoshimasa Funakawa, Mai Aoyama
  • Patent number: 11661642
    Abstract: A high-strength steel sheet includes a steel structure with: ferrite being 35% to 80%, martensite being 5% to 35%, and tempered martensite being 0% to 5% in terms of area fraction; retained austenite being 8% or more in terms of volume fraction; an average grain size of: the ferrite being 6 ?m or less; and the retained austenite being 3 ?m or less; a value obtained by dividing an area fraction of blocky austenite by a sum of area fractions of lath-like austenite and the blocky austenite being 0.6 or more; a value obtained by dividing, by mass %, an average Mn content in the retained austenite by an average Mn content in the ferrite being 1.5 or more; and a value obtained by dividing, by mass %, an average C content in the retained austenite by an average C content in the ferrite being 3.0 or more.
    Type: Grant
    Filed: March 20, 2019
    Date of Patent: May 30, 2023
    Assignee: JFE STEEL CORPORATION
    Inventors: Kazuki Endo, Yoshiyasu Kawasaki, Yuki Toji, Yoshimasa Funakawa, Mai Aoyama
  • Publication number: 20230160032
    Abstract: A steel sheet having a tensile strength (TS) of 780 MPa or more and less than 1180 MPa, high LME resistance, and good weld fatigue properties. The steel sheet has a specific chemical composition and a specific steel microstructure. Crystal grains containing an oxide of Si and/or Mn in a region within 4.9 ?m in a thickness direction from a surface of the steel sheet have an average grain size in the range of 3 to 10 ?m, the lowest Si concentration LSi and the lowest Mn concentration LMn in the region within 4.9 ?m in the thickness direction from the surface of the steel sheet and a Si concentration TSi and a Mn concentration TMn at a quarter thickness position of the steel sheet satisfy a specified formula.
    Type: Application
    Filed: March 25, 2021
    Publication date: May 25, 2023
    Applicant: JFE STEEL CORPORATION
    Inventors: Lingling YANG, Yoshiyasu KAWASAKI, Hidekazu MINAMI, Tatsuya NAKAGAITO, Shotaro TERASHIMA, Shunsuke YAMAMOTO, Katsuya HOSHINO, Yuki TAKEDA
  • Publication number: 20230151451
    Abstract: A steel sheet with a tensile strength (TS) of 1180 MPa or more, a member, and a method for producing them. In a region of the steel sheet within 4.9 ?m in the thickness direction, a region with a Si concentration not more than one-third of the Si concentration in the chemical composition of the steel sheet and with a Mn concentration not more than one-third of the Mn concentration in the chemical composition of the steel sheet has a thickness of 1.0 ?m or more. The lowest Si concentration LSi and the lowest Mn concentration LMn in the region within 4.9 ?m in the thickness direction from the surface of the steel sheet and a Si concentration TSi and a Mn concentration TMn at a quarter thickness position of the steel sheet satisfy the following formula (1): LSi+LMn?(TSi+TMn)/4??(1).
    Type: Application
    Filed: March 25, 2021
    Publication date: May 18, 2023
    Applicant: JFE STEEL CORPORATION
    Inventors: Yoshiyasu KAWASAKI, Lingling YANG, Shotaro TERASHIMA, Tatsuya NAKAGAITO, Shunsuke YAMAMOTO, Katsuya HOSHINO, Yuki TAKEDA
  • Patent number: 11643702
    Abstract: A method for producing a high-strength hot-dip galvannealed steel sheet, in which a high-strength steel sheet is used as a base material, includes a rolling step (x) of rolling a hot-dip galvannealed steel sheet with a coating layer having an Fe concentration of 8% to 17% by mass, and a heat treatment step (y) of heating the coated steel sheet which has been subjected to the rolling step (x) under the conditions satisfying the following formulae (1) and (2): (273+T)×(20+2×log10(t))?8000??(1) 40?T?160??(2) where T: heating temperature (° C.) of the coated steel sheet, and t: holding time (hr) at the heating temperature T.
    Type: Grant
    Filed: October 1, 2021
    Date of Patent: May 9, 2023
    Assignee: JFE Steel Corporation
    Inventors: Satoshi Maeda, Yoshiyasu Kawasaki, Yusuke Fushiwaki, Mai Aoyama
  • Patent number: 11643700
    Abstract: A high-strength steel includes a steel structure with: in area fraction, 60.0% to less than 90.0% of ferrite, 0% to less than 5.0% of unrecrystallized ferrite, 2.0% to 25.0% of martensite, 0% to 5.0% of carbide, and 0% to 3.0% of bainite; in volume fraction, more than 7.0% of retained austenite; in a cross-sectional view of 100 ?m×100 ?m, a value obtained by dividing number of retained austenite that are not adjacent to retained austenite whose crystal orientations are different by a total number of retained austenite being less than 0.80, an average crystal grain size of the ferrite being 6.0 ?m or less, an average crystal grain size of the retained austenite being 3.0 ?m or less, and a value obtained by dividing, by mass %, an average content of Mn in the retained austenite by an average content of Mn in steel being 1.50 or more.
    Type: Grant
    Filed: March 20, 2019
    Date of Patent: May 9, 2023
    Assignee: JFE STEEL CORPORATION
    Inventors: Yoshiyasu Kawasaki, Kazuki Endo, Yuki Toji, Yoshimasa Funakawa, Satoshi Maeda, Mai Aoyama
  • Publication number: 20230129828
    Abstract: A steel sheet with a tensile strength (TS) of 780 MPa or more and less than 1180 MPa, a member, and a method for producing them. In a region of the steel sheet within 4.9 ?m in the thickness direction, a region with a Si concentration not more than one-third of the Si concentration in the chemical composition of the steel sheet and with a Mn concentration not more than one-third of the Mn concentration in the chemical composition of the steel sheet has a thickness of 1.0 ?m or more. The lowest Si concentration LSi and the lowest Mn concentration LMn in the region within 4.9 ?m from the surface of the steel sheet and a Si concentration TSi and a Mn concentration TMn at a quarter thickness position of the steel sheet satisfy the following formula (1): LSi+LMn?(TSi+TMn)/4??(1).
    Type: Application
    Filed: March 25, 2021
    Publication date: April 27, 2023
    Applicant: JFE STEEL CORPORATION
    Inventors: Yoshiyasu KAWASAKI, Lingling YANG, Shotaro TERASHIMA, Hidekazu MINAMI, Tatsuya NAKAGAITO, Shunsuke YAMAMOTO, Katsuya HOSHINO, Yuki TAKEDA
  • Publication number: 20230127243
    Abstract: A steel sheet having a tensile strength (TS) of 1180 MPa or more, high LME resistance, and good weld fatigue properties. The steel sheet has a specific chemical composition and a specific steel microstructure. Crystal grains containing an oxide of Si and/or Mn in a region within 4.9 ?m in a thickness direction from a surface of the steel sheet have an average grain size in the range of 3 to 10 ?m, the lowest Si concentration LSi and the lowest Mn concentration LMn in the region within 4.9 ?m in the thickness direction from the surface of the steel sheet and a Si concentration TSi and a Mn concentration TMn at a quarter thickness position of the steel sheet satisfy a specified formula.
    Type: Application
    Filed: March 25, 2021
    Publication date: April 27, 2023
    Applicant: JFE STEEL CORPORATION
    Inventors: Lingling YANG, Yoshiyasu KAWASAKI, Tatsuya NAKAGAITO, Shotaro TERASHIMA, Shunsuke YAMAMOTO, Katsuya HOSHINO, Yuki TAKEDA
  • Publication number: 20230082367
    Abstract: To obtain a high-strength hot-dip galvanized steel sheet having excellent surface appearance even in the case where a steel strip containing Mn at a predetermined ratio or more to Si is subjected to hot-dip galvanizing treatment, a method of producing a hot-dip galvanized steel sheet using a continuous hot-dip galvanizing apparatus comprises: subjecting a steel strip to annealing, by conveying it in an annealing furnace; and subjecting the steel strip discharged from a cooling zone to hot-dip galvanizing using a hot-dip galvanizing line, to obtain a hot-dip galvanized steel sheet. The steel strip has a chemical composition containing, in mass %, Mn: 1.7% or more and 3.5% or less and Si: 0.2% or more and 1.05% or less and satisfying [Si]/[Mn]?0.30. The chemical composition, a dew point of an atmosphere in the soaking zone, and a delivery temperature of the heating zone satisfy Formula (1).
    Type: Application
    Filed: November 19, 2020
    Publication date: March 16, 2023
    Applicant: JFE STEEL CORPORATION
    Inventors: Shunsuke YAMAMOTO, Shotaro TERASHIMA, Yuki TAKEDA, Michitaka SAKURAI, Katsuya HOSHINO, Yoshiyasu KAWASAKI
  • Patent number: 11597983
    Abstract: A method for producing a high-strength hot-dip galvannealed steel sheet, in which a high-strength steel sheet is used as a base material, includes a rolling step (x) of rolling a hot-dip galvannealed steel sheet with a coating layer having an Fe concentration of 8% to 17% by mass, and a heat treatment step (y) of heating the coated steel sheet which has been subjected to the rolling step (x) under the conditions satisfying the following formulae (1) and (2): (273+T)×(20+2×log10(t))?8000??(1) 40?T?160??(2) where T: heating temperature (° C.) of the coated steel sheet, and t: holding time (hr) at the heating temperature T.
    Type: Grant
    Filed: March 26, 2019
    Date of Patent: March 7, 2023
    Assignee: JFE Steel Corporation
    Inventors: Satoshi Maeda, Yoshiyasu Kawasaki, Yusuke Fushiwaki, Mai Aoyama