Patents by Inventor Muneka Iwasawa

Muneka Iwasawa 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: 12180593
    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: Grant
    Filed: September 25, 2020
    Date of Patent: December 31, 2024
    Assignee: JFE Steel Corporation
    Inventors: Yoshiyasu Kawasaki, Yuki Toji, Muneka Iwasawa, Takayuki Futatsuka, Kentaro Sato
  • 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