Patents by Inventor Sae Hamamoto

Sae Hamamoto 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: 20220298592
    Abstract: A low-strength steel sheet for hot stamping according to an aspect of the present invention satisfies a predetermined chemical composition, the Ac3 point (° C.) represented by Equation (1) is 890° C. or more, and an area ratio of ferrite at a depth to be ¼ of a steel sheet thickness is 80% or more. Ac3 point (° C.)=910?203×[C]1/2+44.7×[Si]?30×[Mn]+700×[P]+400×[Al]+400×[Ti] . . . (1) In Equation (1), [C], [Si], [Mn], [P], [Al], and [Ti] are values denoting the percentage contents of C, Si, Mn, P, Al, and Ti in terms of % by mass, respectively.
    Type: Application
    Filed: August 18, 2020
    Publication date: September 22, 2022
    Applicant: Kabushiki Kaisha Kobe Seiko Sho (Kobe Steel, Ltd.)
    Inventors: Sae HAMAMOTO, Tatsuya ASAI
  • Publication number: 20210054488
    Abstract: A steel plate for hot stamping contains, in % by mass, C: 0.25% or more and 0.4% or less, Si: 1.05% or more and 1.4% or less, Mn: 0% or more and 1.4% or less, Cr: 0.6% or more and 3.0% or less, P: 0% or more and 0.03% or less, S: 0% or more and 0.02% or less, Al: 0.01% or more and 1% or less, N: 0% or more and 0.01% or less, B: 0.0005% or more and 0.005% or less, Ti: 0.005% or more and 0.1% or less, and iron and inevitable impurities as remainder. This steel plate for hot stamping exhibits excellent hardness stability in addition to a balance between strength and toughness as a relational expression of [C]2/9[Si]+7/9[Mn]+8/9[Cr]?7/4>0 is satisfied.
    Type: Application
    Filed: March 19, 2019
    Publication date: February 25, 2021
    Applicant: Kabushiki Kaisha Kobe Seiko Sho (Kobe Steel, Ltd.)
    Inventors: Haruka ARAKI, Sae HAMAMOTO, Tatsuya ASAI
  • Publication number: 20190017142
    Abstract: An aspect of the present invention is a steel sheet for quench hardening, satisfying a prescribed composition and having a Mn concentration satisfying the formula (1): S1+S2<?10×[Mn]+44 (1), where [Mn] is Mn concentration in a steel sheet analyzed by inductively coupled plasma emission spectrography (% by mass); S1 is an area % of the region where the Mn concentration analyzed by an electron beam microprobe analyzer in the structure at a position of ¼ of the steel sheet thickness is two times or more the [Mn]; and S2 is an area % of the region where the Mn concentration analyzed by an electron beam microprobe analyzer in the structure at a position of ¼ of the steel sheet thickness is 0.5 times or less the [Mn].
    Type: Application
    Filed: January 23, 2017
    Publication date: January 17, 2019
    Applicant: KABUSHIKI KAISHA KOBE SEIKO SHO (Kobe Steel, Ltd.)
    Inventors: Sae HAMAMOTO, Tatsuya ASAI, Hiroyuki OMORI
  • Patent number: 8449988
    Abstract: A cold-rolled steel sheet has a chemical composition of C: 0.12% to 0.3%, Si: 0.5% or less, Mn: less than 1.5%, Al: 0.15% or less, N: 0.01% or less, P: 0.02% or less, and S: 0.01% or less, with the remainder including iron and inevitable impurities and has a martensite single-phase structure as its steel microstructure. In a surface region of the steel sheet from the surface to a depth one-tenth the gauge, the number density of n-ary groups of inclusions determined by specific n-th determinations is 120 or less per 100 cm2 of a rolling plane, where the distance in steel sheet rolling direction between outermost surfaces of two outermost particles of the group of inclusions is 100 ?m or more. The steel sheet is a high-strength cold-rolled steel sheet which has a sufficiently minimized rate of bending fracture starting from inclusions and thereby has excellent bending workability.
    Type: Grant
    Filed: May 3, 2011
    Date of Patent: May 28, 2013
    Assignee: Kobe Steel, Ltd.
    Inventors: Atsuhiro Shiraki, Sae Hamamoto, Yukihiro Utsumi, Tetsuji Hoshika, Yuichi Futamura
  • Publication number: 20110287280
    Abstract: A cold-rolled steel sheet has a chemical composition of C: 0.12% to 0.3%, Si: 0.5% or less, Mn: less than 1.5%, Al: 0.15% or less, N: 0.01% or less, P: 0.02% or less, and S: 0.01% or less, with the remainder including iron and inevitable impurities and has a martensite single-phase structure as its steel microstructure. In a surface region of the steel sheet from the surface to a depth one-tenth the gauge, the number density of n-ary groups of inclusions determined by specific n-th determinations is 120 or less per 100 cm2 of a rolling plane, where the distance in steel sheet rolling direction between outermost surfaces of two outermost particles of the group of inclusions is 100 ?m or more. The steel sheet is a high-strength cold-rolled steel sheet which has a sufficiently minimized rate of bending fracture starting from inclusions and thereby has excellent bending workability.
    Type: Application
    Filed: May 3, 2011
    Publication date: November 24, 2011
    Applicant: Kabushiki Kaisha Kobe Seiko Sho (Kobe Steel, Ltd.)
    Inventors: Atsuhiro SHIRAKI, Sae Hamamoto, Yukihiro Utsumi, Tetsuji Hoshika, Yuichi Futamura