公开(公告)号：US20240376562A1

公开(公告)日：2024-11-14

申请号：US18564791

申请日：2022-05-19

Applicant: JFE Steel Corporation

Inventor： Junya Tobata ,  Yuki Toji

IPC: C21D9/46 ,  C21D1/18 ,  C21D6/00 ,  C21D8/02 ,  C22C38/00 ,  C22C38/02 ,  C22C38/04 ,  C22C38/06 ,  C22C38/08 ,  C22C38/10 ,  C22C38/12 ,  C22C38/14 ,  C22C38/16 ,  C22C38/38 ,  C22C38/60

Abstract: A high strength steel sheet includes a specific microstructure having a specific chemical composition and satisfying the formulas (1) and (2) defined below: KAM ⁢ ( S ) / KAM ⁢ ( C )

公开(公告)号：US20240287636A1

公开(公告)日：2024-08-29

申请号：US18564783

申请日：2022-05-19

Applicant: JFE Steel Corporation

Inventor： Junya Tobata ,  Yuki Toji ,  Hidekazu Minami

IPC: C21D9/46 ,  C21D8/02 ,  C22C38/00 ,  C22C38/02 ,  C22C38/04 ,  C22C38/06 ,  C23C2/06 ,  C23C2/40 ,  C25D3/22

CPC classification number: C21D9/46 ,  C21D8/0226 ,  C21D8/0236 ,  C21D8/0273 ,  C22C38/001 ,  C22C38/002 ,  C22C38/02 ,  C22C38/04 ,  C22C38/06 ,  C23C2/06 ,  C23C2/40 ,  C25D3/22 ,  C21D2211/001 ,  C21D2211/002 ,  C21D2211/005 ,  C21D2211/008

Abstract: A high strength steel sheet includes a specific microstructure having a specific chemical composition and satisfying the formulas (1) and (2) defined below:









KAM
⁡
(
S
)

/

KAM
⁡
(
C
)

公开(公告)号：US11643700B2

公开(公告)日：2023-05-09

申请号：US17043514

申请日：2019-03-20

Applicant: JFE STEEL CORPORATION

Inventor： Yoshiyasu Kawasaki ,  Kazuki Endo ,  Yuki Toji ,  Yoshimasa Funakawa ,  Satoshi Maeda ,  Mai Aoyama

IPC: C21D9/46 ,  B32B15/00 ,  C21D6/00 ,  C21D8/00 ,  C22C38/00 ,  B32B15/01 ,  C21D8/02 ,  C22C38/02 ,  C22C38/04 ,  C22C38/06 ,  C22C38/42 ,  C22C38/44 ,  C22C38/46 ,  C22C38/48 ,  C22C38/50 ,  C22C38/54 ,  C23C2/02 ,  C23C2/06 ,  C23C2/28 ,  C23C2/40

CPC classification number: C21D9/46 ,  B32B15/013 ,  C21D6/004 ,  C21D6/005 ,  C21D6/008 ,  C21D8/0205 ,  C21D8/0226 ,  C21D8/0236 ,  C21D8/0263 ,  C22C38/001 ,  C22C38/002 ,  C22C38/005 ,  C22C38/008 ,  C22C38/02 ,  C22C38/04 ,  C22C38/06 ,  C22C38/42 ,  C22C38/44 ,  C22C38/46 ,  C22C38/48 ,  C22C38/50 ,  C22C38/54 ,  C23C2/02 ,  C23C2/06 ,  C23C2/28 ,  C23C2/40 ,  C21D2211/001 ,  C21D2211/003 ,  C21D2211/005 ,  C21D2211/008

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 μm×100 μm, 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 μm or less, an average crystal grain size of the retained austenite being 3.0 μm 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.

公开(公告)号：US11447841B2

公开(公告)日：2022-09-20

申请号：US16349443

申请日：2017-11-15

Applicant: JFE STEEL CORPORATION

Inventor： Yoshiyasu Kawasaki ,  Takako Yamashita ,  Masayasu Ueno ,  Yuki Toji ,  Takashi Kobayashi ,  Yoshimasa Funakawa

IPC: C21D8/02 ,  C23C2/12 ,  C23C2/40 ,  C22C38/00 ,  C22C38/06 ,  C22C38/02 ,  C22C38/14 ,  C22C38/60 ,  C22C38/38 ,  C22C38/12 ,  C22C38/16 ,  C22C38/08 ,  C21D9/46 ,  C23C2/02 ,  C22C38/04 ,  C21D6/00 ,  C23C2/06

Abstract: To provide a high-strength steel sheet with excellent ductility and hole expansion formability, a yield ratio of less than 68%, and a tensile strength of 590 MPa or more, by having a predetermined chemical composition and a microstructure where ferrite is 35% or more and 80% or less and martensite is 5% or more and 25% or less in area ratio, retained austenite is 8% or more in volume fraction, the average grain size of ferrite, martensite and retained austenite is 6.0 μm or less, 3.0 μm or less and 3.0 μm or less respectively, the average aspect ratio of crystal grain of ferrite, martensite and retained austenite is each more than 2.0 and 15.0 or less, and the value obtained by dividing the Mn content (mass %) in retained austenite by the Mn content (mass %) in ferrite is 2.0 or more.

公开(公告)号：US20220267876A1

公开(公告)日：2022-08-25

申请号：US17770116

申请日：2020-10-08

Applicant: JFE Steel Corporation

Inventor： Kazuki Endoh ,  Yoshiyasu Kawasaki ,  Yuki Toji

IPC: C21D9/46 ,  C21D8/02 ,  B32B15/01 ,  C22C38/38 ,  C22C38/16 ,  C22C38/12 ,  C22C38/60 ,  C22C38/08 ,  C22C38/06 ,  C22C38/04 ,  C22C38/02 ,  C22C38/00 ,  C23C2/06 ,  C23C2/28 ,  C23C2/40

Abstract: Provided is a high strength steel sheet that has a predetermined chemical composition and is manufactured under optimum conditions, the high strength steel sheet having a steel microstructure including, by area, ferrite: 30% or more and 80% or less, martensite: 5% or more and 35% or less, and retained austenite: 8% or more, wherein the quotient of the area fraction of grains of the retained austenite, the grains having an aspect ratio of 2.0 or more and a minor axis length of 1 μm or less, divided by the total area fraction of the retained austenite is 0.3 or more, wherein the quotient of the average Mn content (mass %) in the retained austenite divided by the average Mn content (mass %) in the ferrite is 1.5 or more.

公开(公告)号：US09574254B2

公开(公告)日：2017-02-21

申请号：US14346786

申请日：2012-09-27

Applicant: JFE Steel Corporation

Inventor： Katsutoshi Takashima ,  Yuki Toji ,  Kohei Hasegawa ,  Shinya Yamaguchi

IPC: C22C38/02 ,  C22C38/04 ,  C22C38/06 ,  C22C38/08 ,  C22C38/14 ,  C22C38/16 ,  C22C38/18 ,  C22C38/26 ,  C23C2/06 ,  C21D9/46 ,  C22C38/12 ,  B32B15/01 ,  C22C38/00 ,  C21D8/02 ,  C22C18/00 ,  C22C18/02

CPC classification number: C22C38/26 ,  B32B15/013 ,  C21D8/0263 ,  C21D9/46 ,  C21D2211/005 ,  C22C18/00 ,  C22C18/02 ,  C22C38/001 ,  C22C38/002 ,  C22C38/005 ,  C22C38/02 ,  C22C38/04 ,  C22C38/06 ,  C22C38/08 ,  C22C38/12 ,  C22C38/14 ,  C22C38/16 ,  C22C38/18 ,  C23C2/06

Abstract: A hot rolled steel sheet has a chemical composition including, by mass %, C: 0.060% to 0.120%; Si: 0.10% to 0.70%; Mn: 1.00% to 1.80%; P: 0.10% or less; S: 0.010% or less; Al: 0.01% to 0.10%; N: 0.010% or less; Nb: 0.010% to 0.100%, wherein Nb is contained so that content of solute Nb is 5% or more relative to the total Nb content; the balance being Fe and incidental impurities. The hot rolled steel sheet has a microstructure containing ferrite of not more than 15 μm in average crystal grain diameter by a volume fraction of not less than 75%, the balance being low-temperature-induced phases. The hot rolled steel sheet can be suitably utilized for manufacturing a cold rolled steel sheet or hot-dip galvanized steel sheet having a tensile strength of 590 MPa or more, excellent in material homogeneity and capable of giving excellent cold rolling property.

Abstract translation: 热轧钢板具有质量％C：0.060〜0.120％的化学成分， Si：0.10〜0.70％ Mn：1.00〜1.80％ P：0.10％以下; S：0.010％以下; Al：0.01〜0.10％ N：0.010％以下; Nb：0.010〜0.100％，其中Nb含量相对于总Nb含量为5％以上; 余量为Fe和杂质。 该热轧钢板的平均结晶粒径为15μm以下的铁素体，其体积分数为75％以上，余量为低温诱导相。 热轧钢板可以适用于制造拉伸强度为590MPa以上的冷轧钢板或热浸镀锌钢板，材料均匀性优异，能够得到优异的冷轧性。

公开(公告)号：US20140332119A1

公开(公告)日：2014-11-13

申请号：US14363171

申请日：2012-12-03

Applicant: JFE STEEL CORPORATION

Inventor： Katsutoshi Takashima ,  Yuki Toji ,  Kohei Hasegawa

IPC: C22C38/34 ,  C22C38/16 ,  C22C38/14 ,  C22C38/00 ,  C22C38/08 ,  C22C38/06 ,  C22C38/04 ,  C22C38/02 ,  C21D8/02 ,  C22C38/12

CPC classification number: C22C38/34 ,  C21D8/0236 ,  C21D8/0263 ,  C21D8/0273 ,  C21D8/0436 ,  C21D9/46 ,  C21D2211/005 ,  C21D2211/009 ,  C22C38/001 ,  C22C38/02 ,  C22C38/04 ,  C22C38/06 ,  C22C38/08 ,  C22C38/12 ,  C22C38/14 ,  C22C38/16 ,  C22C38/58

Abstract: A high strength cold rolled steel sheet has a chemical composition including, by mass %, C: 0.06 to 0.13%, Si: 1.2 to 2.3%, Mn: 0.6 to 1.6%, P: not more than 0.10%, S: not more than 0.010%, Al: 0.01 to 0.10% and N: not more than 0.010%, the balance comprising Fe and inevitable impurities. The steel sheet includes a microstructure containing not less than 90% in terms of volume fraction of ferrite with an average grain diameter of less than 20 μm and 1.0 to 10% in terms of volume fraction of pearlite with an average grain diameter of less than 5 μm. The ferrite has an average Vickers hardness of not less than 130. The steel sheet has a yield ratio of not less than 65% and a tensile strength of not less than 590 MPa.

Abstract translation: 高强度冷轧钢板具有以质量％计含有C：0.06〜0.13％，Si：1.2〜2.3％，Mn：0.6〜1.6％，P：0.10％以下，S：以上的化学成分 0.010％以下，Al：0.01〜0.10％，N：不大于0.010％，余量由Fe和不可避免的杂质构成。 该钢板包括平均粒径小于20μm的铁素体的体积分率为90％以上且平均粒径小于5的珠光体的体积分率为1.0〜10％的微结构 μm。 该铁素体的平均维氏硬度为130以上。钢板的屈服比为65％以上，拉伸强度为590MPa以上。

公开(公告)号：US20250137084A1

公开(公告)日：2025-05-01

申请号：US18683349

申请日：2022-08-05

Applicant: JFE Steel Corporation

Inventor： Yusuke Wada ,  Hidekazu Minami ,  Yuki Toji

IPC: C21D9/46 ,  C21D6/00 ,  C21D8/02 ,  C22C38/00 ,  C22C38/02 ,  C22C38/04 ,  C22C38/06 ,  C22C38/08 ,  C22C38/10 ,  C22C38/12 ,  C22C38/14 ,  C22C38/16 ,  C22C38/32 ,  C22C38/38 ,  C22C38/60

Abstract: There is provided a high-strength steel sheet having a tensile strength of 1180 MPa or more. The high-strength steel sheet having a component composition containing C: 0.090 mass % or more and 0.390 mass % or less, Si: 0.01 mass % or more and 2.00 mass % or less, Mn: 2.00 mass % or more and 4.00 mass % or less, P: 0.100 mass % or less, S: 0.0200 mass % or less, Al: 1.000 mass % or less, N: 0.0100 mass % or less, and O: 0.0100 mass % or less, with a remaining part consisting of Fe and inevitable impurities; and a microstructure. In the microstructure, an area ratio of martensite is 70% or more, an area ratio of ferrite is 10% or less, an area ratio of retained austenite is 10% or less, and a proportion of the number of martensite blocks in which metastable carbides are present to the number of martensite blocks is 2% or more.

公开(公告)号：US12221668B2

公开(公告)日：2025-02-11

申请号：US17770116

申请日：2020-10-08

Applicant: JFE Steel Corporation

Inventor： Kazuki Endoh ,  Yoshiyasu Kawasaki ,  Yuki Toji

IPC: C21D9/46 ,  B32B15/01 ,  C21D8/02 ,  C22C38/00 ,  C22C38/02 ,  C22C38/04 ,  C22C38/06 ,  C22C38/08 ,  C22C38/12 ,  C22C38/16 ,  C22C38/38 ,  C22C38/60 ,  C23C2/06 ,  C23C2/28 ,  C23C2/40

Abstract: Provided is a high strength steel sheet that has a predetermined chemical composition and is manufactured under optimum conditions, the high strength steel sheet having a steel microstructure including, by area, ferrite: 30% or more and 80% or less, martensite: 5% or more and 35% or less, and retained austenite: 8% or more, wherein the quotient of the area fraction of grains of the retained austenite, the grains having an aspect ratio of 2.0 or more and a minor axis length of 1 μm or less, divided by the total area fraction of the retained austenite is 0.3 or more, wherein the quotient of the average Mn content (mass %) in the retained austenite divided by the average Mn content (mass %) in the ferrite is 1.5 or more.

公开(公告)号：US12180593B2

公开(公告)日：2024-12-31

申请号：US17766398

申请日：2020-09-25

Applicant: JFE Steel Corporation

Inventor： Yoshiyasu Kawasaki ,  Yuki Toji ,  Muneka Iwasawa ,  Takayuki Futatsuka ,  Kentaro Sato

IPC: C22C38/16 ,  C21D1/18 ,  C21D6/00 ,  C21D8/02 ,  C21D9/46 ,  C22C38/00 ,  C22C38/02 ,  C22C38/04 ,  C22C38/06 ,  C22C38/08 ,  C22C38/12 ,  C22C38/14 ,  C22C38/38 ,  C22C38/60 ,  C23C2/02 ,  C23C2/06 ,  C23C2/28 ,  C23C2/40 ,  C25D3/22 ,  C25D7/06

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 μm or less, and the retained austenite has an average grain size of 2.0 μm or less. A value obtained by dividing a volume fraction Vγa by a volume fraction Vγb is 0.40 or greater, where the volume fraction Vγa 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 Vγb is a volume fraction of retained austenite before the warm tensile test at 150° C.