公开(公告)号：US20240044822A1

公开(公告)日：2024-02-08

申请号：US18256096

申请日：2021-09-06

Applicant: JFE STEEL CORPORATION

Inventor： Tomoharu ISHIDA ,  Seiya SUGAWARA ,  Kenji TSUZUMI

IPC: G01N23/2251 ,  G01N23/2252 ,  G01N33/2028

CPC classification number: G01N23/2251 ,  G01N23/2252 ,  G01N33/2028 ,  G01N2223/418 ,  G01N2223/624

Abstract: A method of evaluating central segregation in steel with excellent correlation with HIC susceptibility is provided. A method of evaluating central segregation in steel includes: taking a sample from a steel, the sample having a cross section including a central segregation area; measuring an area ratio of an inclusion containing a segregation metal element in a region to be measured including the central segregation area in the cross section; and evaluating central segregation in the steel based on the area ratio measured.

公开(公告)号：US20180363088A1

公开(公告)日：2018-12-20

申请号：US15735678

申请日：2016-08-10

Applicant: JFE STEEL CORPORATION

Inventor： Kenji TSUZUMI ,  Yoshiyasu KAWASAKI ,  Yuji MIKI

IPC: C21D9/46 ,  C22C38/50 ,  C22C38/58 ,  C22C38/32 ,  C22C38/26 ,  C22C38/24 ,  C22C38/22 ,  C22C38/20 ,  B22D11/00 ,  B22D11/124 ,  C21D8/02 ,  C21D6/00 ,  C22C38/06 ,  C22C38/02 ,  C22C38/00 ,  C23C2/12 ,  C23C2/28 ,  C23C2/40 ,  C23C28/02 ,  B32B15/01

Abstract: A high strength steel sheet having excellent surface quality and formability with a tensile strength of 980 MPa or more and a TS-El balance of 30000 MPa % or more is provided. A high strength steel sheet comprises: a chemical composition containing C: 0.08% to 0.30%, Si: 2.0% or less, Mn: more than 3.0% and 10.0% or less, P: 0.05% or less, S: 0.01% or less, Al: 1.5% or less, Ti: 0.010% to 0.300%, and N: 0.0020% to 0.0100% in a range satisfying 1.1≤(Ti+Mn1/2/400)/(0.01+5N)≤6.0; and a microstructure including a retained austenite phase and a ferrite phase, wherein a ratio γMn/αMn of an average Mn concentration (γMn) of the retained austenite phase to an average Mn concentration (αMn) of the ferrite phase is 1.5 or more.

公开(公告)号：US20250051873A1

公开(公告)日：2025-02-13

申请号：US18720754

申请日：2022-12-05

Applicant: JFE Steel Corporation

Inventor： Yuta SAKURAI ,  Tomoya ODAGAKI ,  Kenji TSUZUMI ,  Akitoshi MATSUI ,  Tetsuo MOCHIDA ,  Naoki KIKUCHI

IPC: C21D9/46 ,  C21D8/02 ,  C22C38/00 ,  C22C38/16

Abstract: A method for producing Cu—Sn-containing steel includes a hot heating step of attaching a flux to a surface of a Cu—Sn-containing cast steel in such an amount that the mass per unit area is 50 g/m2 or more and 5000 g/m2 or less, and heating the Cu—Sn-containing cast steel at a temperature of 1000° C. or above and 1400° C. or below, the flux including at least any of B2O3, P2O5, K2O, PbO, Na2O—FeO, Na2O—SiO2, Na2O—TiO2, and Li2O—SiO2 components and being such that the liquid phase ratio at 1000° C. is 10 mass % or more; and a hot working step of hot working the Cu—Sn-containing cast steel.

公开(公告)号：US20220226886A1

公开(公告)日：2022-07-21

申请号：US17616525

申请日：2020-06-03

Applicant: JFE STEEL CORPORATION

Inventor： Kenji TSUZUMI ,  Hideya MASAKI

IPC: B22D11/16 ,  B22D11/108 ,  C22C38/38 ,  C22C38/22 ,  C22C38/06 ,  C22C38/02 ,  C22C38/00 ,  C04B35/14

Abstract: A mold powder which prevents surface defects from occurring on a surface of a cast slab of Al-containing hypo-peritectic steel having Al: 0.2% to 2.0%, by mass %, and, in a hypo-peritectic region, C: 0.08% to 0.17%, by mass %. The mold powder includes CaO, SiO2, Na2O, Li2O, F, and C. Li2O/Na2O is 0.6 or more, 1.0+0.05×Al≤CaO/SiO2≤2.0−0.35×Al, 10