公开(公告)号：US20140349134A1

公开(公告)日：2014-11-27

申请号：US14370502

申请日：2012-12-26

Applicant: JFE Steel Corporation

Inventor： Hideki Nagano ,  Daisuke Harako ,  Yuji Tanaka

IPC: B32B15/01

CPC classification number: B32B15/013 ,  C21D8/0226 ,  C21D8/0263 ,  C21D8/0278 ,  C21D9/46 ,  C21D2211/004 ,  C22C18/00 ,  C22C38/001 ,  C22C38/02 ,  C22C38/04 ,  C22C38/06 ,  C22C38/12 ,  C22C38/14 ,  C23C2/06 ,  C23C2/28 ,  Y10T428/12799

Abstract: A hot-dip galvannealed steel sheet has excellent chipping resistance and after-coating adherence while ensuring corrosion resistance. The hot-dip galvannealed steel sheet has a base material steel sheet having a predetermined component composition and a hot-dip galvannealing layer containing by mass 7-15% Fe provided on the base material steel sheet surface, wherein the hot-dip galvannealed steel sheet contains within the hot-dip galvannealing layer at least 0.01% by mass of a precipitate including one or more elements selected from the group consisting of Ti, Nb, V, Mo, and W.

Abstract translation: 热浸镀锌合金化钢板具有优异的耐崩裂性和后涂层粘附性，同时确保耐腐蚀性。 热镀合金化热镀锌钢板具有预定的组成成分的基材钢板和在基材钢板表面上设置的质量为7〜15％的Fe的热浸镀锌合金层，其中，浸渍热浸镀锌钢板 在热浸镀锌层内含有至少0.01质量％的包含选自Ti，Nb，V，Mo和W中的一种或多种元素的沉淀物。

公开(公告)号：US12258646B2

公开(公告)日：2025-03-25

申请号：US17593062

申请日：2020-02-21

Applicant: JFE STEEL CORPORATION

Inventor： Hidekazu Minami ,  Yuji Tanaka ,  Takeshi Yokota

IPC: C21D9/46 ,  B32B15/01 ,  C21D6/00 ,  C21D8/02 ,  C22C38/00 ,  C22C38/02 ,  C22C38/06 ,  C22C38/20 ,  C22C38/22 ,  C22C38/24 ,  C22C38/26 ,  C22C38/28 ,  C22C38/30 ,  C22C38/32 ,  C22C38/38 ,  C22C38/40 ,  C23C2/02 ,  C23C2/28

Abstract: A high-strength steel sheet comprises: a chemical composition containing C, Si, Mn, P, S, Al, N, Mo, Cr, Ca, and Sb with a balance consisting of Fe and inevitable impurities, wherein [% Si], [% Mn], [% P], [% Mo], and [% Cr] satisfy a predetermined relationship; a steel microstructure that contains ferrite, hard phase, and retained austenite and in which a carbon concentration in the retained austenite is 0.55% or more and 1.10% or less, an amount of diffusible hydrogen in the steel sheet is 0.80 mass ppm or less, a surface layer softening thickness is 5 μm or more and 150 μm or less, and a corresponding grain boundary frequency in a surface layer of the steel sheet after a high-temperature tensile test is 0.45 or less; and a tensile strength of 980 MPa or more.

公开(公告)号：US11939642B2

公开(公告)日：2024-03-26

申请号：US17283840

申请日：2019-08-20

Applicant: JFE STEEL CORPORATION

Inventor： Hidekazu Minami ,  Yuji Tanaka ,  Junya Tobata ,  Takeshi Yokota

IPC: C21D9/46 ,  C21D8/02 ,  C22C38/00 ,  C22C38/02 ,  C22C38/04 ,  C22C38/06 ,  C23C2/02 ,  C23C2/06 ,  C23C2/12 ,  C23C2/28 ,  C23G1/00 ,  C25D3/22 ,  C25D3/44

CPC classification number: C21D9/46 ,  C21D8/0226 ,  C21D8/0236 ,  C21D8/0273 ,  C22C38/002 ,  C22C38/02 ,  C22C38/04 ,  C22C38/06 ,  C23C2/02 ,  C23C2/0224 ,  C23C2/024 ,  C23C2/06 ,  C23C2/12 ,  C23C2/28 ,  C23G1/00 ,  C25D3/22 ,  C25D3/44 ,  C21D2211/001 ,  C21D2211/008

Abstract: A high-strength steel sheet having a tensile strength of 1,180 MPa or more, and specified chemical composition. The steel sheet includes a steel structure in which an area fraction of martensite having a carbon concentration of more than 0.7×[% C] and less than 1.5×[% C] is 55% or more, an area fraction of tempered martensite having a carbon concentration of 0.7×[% C] or less is 5% or more and 40% or less, a ratio of a carbon concentration in retained austenite to a volume fraction of retained austenite is 0.05 or more and 0.40 or less, and the martensite and the tempered martensite each have an average grain size of 5.3 μm or less, where [% C] represents the content, by mass %, of compositional element C in steel.

公开(公告)号：US11926881B2

公开(公告)日：2024-03-12

申请号：US17636714

申请日：2020-06-19

Applicant: JFE STEEL CORPORATION

Inventor： Yuji Tanaka ,  Hidekazu Minami ,  Naoki Takayama ,  Takako Yamashita

IPC: C21D9/46 ,  B32B15/01 ,  C21D6/00 ,  C21D8/02 ,  C22C38/00 ,  C22C38/02 ,  C22C38/06 ,  C22C38/08 ,  C22C38/10 ,  C22C38/12 ,  C22C38/16 ,  C22C38/28 ,  C22C38/32 ,  C22C38/38 ,  C23C2/28 ,  C23C2/40

CPC classification number: C21D9/46 ,  B32B15/013 ,  C21D6/001 ,  C21D6/002 ,  C21D6/005 ,  C21D6/007 ,  C21D6/008 ,  C21D8/0205 ,  C21D8/0226 ,  C21D8/0236 ,  C22C38/001 ,  C22C38/002 ,  C22C38/005 ,  C22C38/02 ,  C22C38/06 ,  C22C38/08 ,  C22C38/10 ,  C22C38/12 ,  C22C38/16 ,  C22C38/28 ,  C22C38/32 ,  C22C38/38 ,  C23C2/29 ,  C23C2/40 ,  C21D2211/002 ,  C21D2211/008 ,  Y10T428/12799

Abstract: A high-strength cold-rolled steel sheet having a high yield ratio and excellent stretch flangeability and a method for manufacturing the steel sheet. The high-strength cold-rolled steel sheet has a chemical composition including, by mass %, C: 0.10 to 0.30%, Si: 0.50 to 2.00%, Mn: 2.5 to 4.0%, P: 0.050% or less, S: 0.020% or less, Al: 0.10% or less, N: 0.01% or less, Ti: 0.100% or less, and B: 0.0003 to 0.0030%, with the balance being Fe and incidental impurities. N and Ti satisfy a specified formula, and the total area fraction of martensite and bainite is 95% or more. The number density of bainite grains having an area of 3 μm2 or more and a carbon concentration of less than 0.7C is 1200 grains/mm2 or less.

公开(公告)号：US11408058B2

公开(公告)日：2022-08-09

申请号：US16485197

申请日：2018-02-09

Applicant: JFE STEEL CORPORATION

Inventor： Hidekazu Minami ,  Takashi Kobayashi ,  Shinjiro Kaneko ,  Yuji Tanaka

IPC: C22C38/04 ,  C22C38/00 ,  C22C38/02 ,  C22C38/06 ,  C22C38/12 ,  C22C38/14 ,  C22C38/60 ,  C23C2/06 ,  C21D8/02 ,  C21D8/04 ,  C21D9/46

Abstract: There is provided a high-strength steel sheet and a method for producing the same. The steel sheet has a specified chemical composition and a microstructure including, in terms of area percentage, 20.0% or more and 60.0% or less ferrite, 40.0% or more and 80.0% or less of a hard phase composed of bainitic ferrite, tempered martensite, fresh martensite, and retained austenite, 35.0% or more and 55.0% or less bainitic ferrite with respect to the entire hard phase, 20.0% or more and 40.0% or less tempered martensite with respect to the entire hard phase, 3.0% or more and 15.0% or less fresh martensite with respect to the entire hard phase, and 5.0% or more and 20.0% or less retained austenite with respect to the entire hard phase.

公开(公告)号：US11408044B2

公开(公告)日：2022-08-09

申请号：US16485083

申请日：2018-02-09

Applicant: JFE STEEL CORPORATION

Inventor： Hidekazu Minami ,  Fusae Shiimori ,  Shinjiro Kaneko ,  Takashi Kobayashi ,  Yuji Tanaka

IPC: C21D9/46 ,  C21D8/02 ,  C21D6/00 ,  C21D1/26 ,  C22C38/24 ,  C22C38/60 ,  C22C38/16 ,  C22C38/14 ,  C22C38/12 ,  C22C38/10 ,  C22C38/08 ,  C22C38/06 ,  C22C38/04 ,  C22C38/02 ,  C22C38/00

Abstract: There is provided a high-strength steel sheet and a method for producing the same. The high-strength steel sheet has a specified chemical composition and a steel microstructure including, by area fraction, 75.0% or more tempered martensite, 1.0% or more and 20.0% or less fresh martensite, and 5.0% or more and 20.0% or less retained austenite. A hardness ratio of the fresh martensite to the tempered martensite is 1.5 or more and 3.0 or less, the ratio of the maximum KAM value in the tempered martensite in the vicinity of the heterophase interface between the tempered martensite and the fresh martensite to the average KAM value in the tempered martensite is 1.5 or more and 30.0 or less, and the average of ratios of grain sizes of prior austenite grains in the rolling direction to those in the thickness direction is 2.0 or less.

公开(公告)号：US10151718B2

公开(公告)日：2018-12-11

申请号：US15528330

申请日：2015-03-23

Applicant: JFE STEEL CORPORATION

Inventor： Yuji Tanaka ,  Takako Yamashita ,  Masayasu Nagoshi

IPC: H01J37/26 ,  G01N23/083 ,  G01N23/2252 ,  G01N23/207 ,  H01J37/28 ,  H01J37/256 ,  H01J37/18

Abstract: The present invention makes it possible to analyze trace carbon in a sample without the effects of contamination. In an electron probe microanalyzer, a liquid nitrogen trap and a plasma or oxygen radical generator are jointly used as a means for suppressing contamination, and two or more carbon detection units for detecting characteristic x-rays of carbon in the sample are provided.