公开(公告)号：US20240360532A1

公开(公告)日：2024-10-31

申请号：US18681864

申请日：2022-06-21

Applicant: JFE STEEL CORPORATION

Inventor： Yuji TANAKA ,  Takeshi NISHIYAMA ,  Masanari TOMOZAWA ,  Kazuki ENDOH ,  Hidekazu MINAMI ,  Junya TOBATA ,  Yuki TOJI

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

CPC classification number: C21D9/46 ,  C21D8/0205 ,  C21D8/0226 ,  C21D8/0236 ,  C21D8/0268 ,  C21D8/0273 ,  C21D8/0278 ,  C22C38/001 ,  C22C38/002 ,  C22C38/02 ,  C22C38/04 ,  C22C38/06 ,  C22C38/12

Abstract: The steel sheet comprising a chemical composition containing C, Si, Mn, P, S, Al, N, Ti, Nb, and B, with the balance being Fe and inevitable impurities, and satisfying predetermined formula, in which the total area ratio of martensite and bainite is 95% or more, the average grain size of prior austenite grains is 10 μm or less, the B concentration at a prior austenite grain boundary is 0.10% or more in mass %, a C-concentrated region is provided along a martensitic grain boundary, and the C-concentrated region has a C concentration of 4.0 times or more than the C content in the steel, and the C-concentrated region has a concentration width of 3 nm or more and 100 nm or less in a direction perpendicular to the martensitic grain boundary and a length of 100 nm or more in a direction parallel to the martensitic grain boundary.

公开(公告)号：US20160186283A1

公开(公告)日：2016-06-30

申请号：US14909253

申请日：2014-07-16

Applicant: JFE STEEL CORPORATION

Inventor： Hidekazu MINAMI ,  Takeshi YOKOTA ,  Kazuhiro SETO

IPC: C21D9/46 ,  C22C38/38 ,  C22C38/28 ,  C22C38/26 ,  C22C38/22 ,  C22C38/16 ,  C22C38/14 ,  C22C38/12 ,  C22C38/08 ,  C22C38/04 ,  C22C38/02 ,  C22C38/00 ,  C23C2/02 ,  C23C2/06 ,  C23C2/28 ,  C23C2/40 ,  C21D8/02 ,  C21D6/00 ,  C22C38/60

Abstract: A high strength steel sheet having a high Young's modulus, the steel sheet having a chemical composition including, by mass %, C: 0.060% or more and 0.150% or less, Si: 0.50% or more and 2.20% or less, Mn: 1.00% or more and 3.00% or less, and one or both of Ti: 0.001% or more and 0.200% or less and Nb: 0.001% or more and 0.200% or less, in which the contents of C, N, S, Ti, and Nb satisfy the equation 500≦C*≦1300. The steel sheet has a microstructure including ferrite in an amount of 20% or more and martensite in an amount of 5% or more, in terms of area ratio, such that the average grain size of the ferrite is 20.0 μm or less and the inverse intensity ratio of γ-fiber for α-fiber is 1.00 or more in the ferrite and the martensite.

Abstract translation: 具有高杨氏模量的高强度钢板，所述钢板的化学成分以质量％计含有C：0.060％以上且0.150％以下，Si：0.50％以上且2.20％以下，Mn： 1.00％以上且3.00％以下，Ti：0.001％以上且0.200％以下，Nb：0.001％以上且0.200％以下的一种以上，C，N，S， Ti和Nb满足方程500＆amp; NlE; C *＆nlE; 1300。 该钢板的面积比为20％以上的铁素体和5％以上的马氏体的组织，铁素体的平均粒径为20.0μm以下， 铁素体和马氏体中α-纤维的γ纤维的强度比为1.00以上。

公开(公告)号：US20240352549A1

公开(公告)日：2024-10-24

申请号：US18574068

申请日：2022-05-17

Applicant: JFE STEEL CORPORATION

Inventor： Yuki TOJI ,  Kazuki ENDOH ,  Hidekazu MINAMI

IPC: C21D3/10 ,  C21D3/06 ,  C21D10/00 ,  C22C38/00 ,  C22C38/02 ,  C22C38/04 ,  C22C38/06 ,  C22C38/08 ,  C22C38/12 ,  C22C38/14 ,  C22C38/16 ,  C22C38/24 ,  C22C38/26 ,  C22C38/38 ,  C22C38/60

CPC classification number: C21D3/10 ,  C21D3/06 ,  C21D10/00 ,  C22C38/001 ,  C22C38/002 ,  C22C38/005 ,  C22C38/008 ,  C22C38/02 ,  C22C38/04 ,  C22C38/06 ,  C22C38/08 ,  C22C38/12 ,  C22C38/14 ,  C22C38/16 ,  C22C38/24 ,  C22C38/26 ,  C22C38/38 ,  C22C38/60

Abstract: Provided are a steel sheet dehydrogenation apparatus, a steel sheet production system, and a steel sheet production method capable of producing a steel sheet excellent in hydrogen embrittlement resistance without changing the mechanical properties of the steel sheet. A dehydrogenation apparatus comprises: a housing configured to house a steel sheet coil obtained by coiling a steel strip; and a vibration application device configured to apply vibration to the steel sheet coil housed in the housing so that the steel sheet coil is caused to vibrate at a frequency of 100 Hz to 100,000 Hz and a maximum amplitude of 10 nm to 500 μm.

公开(公告)号：US20240287637A1

公开(公告)日：2024-08-29

申请号：US18572182

申请日：2022-05-31

Applicant: JFE STEEL CORPORATION

Inventor： Hidekazu MINAMI ,  Yusuke WADA ,  Yuki TOJI ,  Takeshi NISHIYAMA ,  Michitoshi SAEKI

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 ,  C22C38/26 ,  C22C38/28 ,  C22C38/32 ,  C22C38/38 ,  C22C38/60

CPC classification number: C21D9/46 ,  C21D1/18 ,  C21D6/001 ,  C21D6/002 ,  C21D6/005 ,  C21D6/007 ,  C21D6/008 ,  C21D8/0205 ,  C21D8/0226 ,  C21D8/0236 ,  C21D8/0263 ,  C21D8/0278 ,  C22C38/001 ,  C22C38/002 ,  C22C38/005 ,  C22C38/008 ,  C22C38/02 ,  C22C38/04 ,  C22C38/06 ,  C22C38/08 ,  C22C38/10 ,  C22C38/12 ,  C22C38/14 ,  C22C38/16 ,  C22C38/26 ,  C22C38/28 ,  C22C38/32 ,  C22C38/38 ,  C22C38/60 ,  C21D2211/001 ,  C21D2211/005 ,  C21D2211/008

Abstract: A high strength steel sheet with a chemical composition containing C, Si, Mn, P, S, Al, N, Nb, Ti, and B, where [% Si]/[% Mn] is 0.10 or more and 0.60 or less, and free Ti content determined from Formula (1), below, is 0.001 mass % or more, with the balance being Fe and inevitable impurity. In a steel sheet surface layer, a total amount of Nb solute and 100 nm or smaller precipitate is 0.002 mass % or more.








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公开(公告)号：US20240263287A1

公开(公告)日：2024-08-08

申请号：US18565655

申请日：2022-03-16

Applicant: JFE STEEL CORPORATION

Inventor： Hidekazu MINAMI ,  Yusuke WADA ,  Yuki TOJI ,  Yoichi MAKIMIZU

IPC: C22C38/04 ,  C21D6/00 ,  C21D8/02 ,  C21D9/46 ,  C22C38/02 ,  C22C38/06 ,  C23C2/02 ,  C23C2/06 ,  C23C2/28 ,  C23C2/40

CPC classification number: C22C38/04 ,  C21D6/005 ,  C21D8/0226 ,  C21D8/0263 ,  C21D8/0268 ,  C21D8/0273 ,  C21D9/46 ,  C22C38/02 ,  C22C38/06 ,  C23C2/024 ,  C23C2/06 ,  C23C2/29 ,  C23C2/40

Abstract: Provided is a hot-dip galvanized steel sheet that has a high YR, as well as high ductility, stretch flangeability, and bendability, improved shear workability, and a TS of 1,180 MPa or more. The base steel sheet of the hot-dip galvanized steel sheet has a defined chemical composition and steel microstructure. In particular, a number ratio of retained austenite (y) having an aspect ratio of 2.0 or less is more than 50%, a number of bins of hardness frequency: 0.25 or more is 1, the area ratio of quenched martensite in a surface layer is 80% or less, a surface layer softening thickness is 10 μm or more and 100 μm or less, and the amount of low temperature range diffusible hydrogen is 0.015 mass ppm or less.

公开(公告)号：US20220251676A1

公开(公告)日：2022-08-11

申请号：US17630504

申请日：2020-06-19

Applicant: JFE STEEL CORPORATION

Inventor： Hidekazu MINAMI ,  Takeshi YOKOTA ,  Yoshiyasu KAWASAKI ,  Shotaro TERASHIMA

IPC: C21D9/46 ,  B32B15/01 ,  C22C38/58 ,  C22C38/44 ,  C22C38/32 ,  C22C38/30 ,  C22C38/28 ,  C22C38/26 ,  C22C38/24 ,  C22C38/20 ,  C22C38/00 ,  C21D8/02 ,  C21D6/00

Abstract: Provided are a high-strength hot-dip galvanized steel sheet that has a tensile strength of 1180 MPa or more and excellent ductility, stretch flangeability, bendability and LME resistance and can manufacture parts with high dimensional accuracy, and its manufacturing method. The high-strength steel sheet with a tensile strength of 1180 MPa or more has a chemical composition containing C, Si, Mn, P, S, Al and N, with [% Si], [% Mn], [% P], [% Mo] and [% Cr] satisfying a predetermined relationship and the balance being Fe and inevitable impurities, and a steel microstructure including ferrite, tempered martensite and bainite, and retained austenite, where the diffusible hydrogen amount in the steel sheet is 0.60 mass ppm or less, a thickness of softened surface layer is 5 μm or more and 150 μm or less, and a frequency of coincidence boundary in the steel sheet surface layer after a high-temperature tensile test is 0.45 or less.

公开(公告)号：US20230160032A1

公开(公告)日：2023-05-25

申请号：US17915696

申请日：2021-03-25

Applicant: JFE STEEL CORPORATION

Inventor： Lingling YANG ,  Yoshiyasu KAWASAKI ,  Hidekazu MINAMI ,  Tatsuya NAKAGAITO ,  Shotaro TERASHIMA ,  Shunsuke YAMAMOTO ,  Katsuya HOSHINO ,  Yuki TAKEDA

IPC: C21D9/46 ,  C23C2/40 ,  C23C2/06 ,  C21D8/02 ,  C22C38/00 ,  C22C38/02 ,  C22C38/04 ,  C22C38/06 ,  B21C47/02

CPC classification number: C21D9/46 ,  C23C2/40 ,  C23C2/06 ,  C21D8/0226 ,  C21D8/0236 ,  C21D8/0273 ,  C22C38/001 ,  C22C38/002 ,  C22C38/02 ,  C22C38/04 ,  C22C38/06 ,  B21C47/02 ,  C21D2211/002 ,  C21D2211/005 ,  C21D2211/008 ,  C21D2211/001

Abstract: A steel sheet having a tensile strength (TS) of 780 MPa or more and less than 1180 MPa, high LME resistance, and good weld fatigue properties. The steel sheet has a specific chemical composition and a specific steel microstructure. Crystal grains containing an oxide of Si and/or Mn in a region within 4.9 μm in a thickness direction from a surface of the steel sheet have an average grain size in the range of 3 to 10 μm, the lowest Si concentration LSi and the lowest Mn concentration LMn in the region within 4.9 μm in the thickness direction from the surface of the steel sheet and a Si concentration TSi and a Mn concentration TMn at a quarter thickness position of the steel sheet satisfy a specified formula.

公开(公告)号：US20220340989A1

公开(公告)日：2022-10-27

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 ,  C22C38/38 ,  C22C38/32 ,  C22C38/28 ,  C22C38/16 ,  C22C38/12 ,  C22C38/10 ,  C22C38/08 ,  C22C38/06 ,  C22C38/02 ,  C22C38/00 ,  C21D8/02 ,  C21D6/00 ,  C23C2/40 ,  C23C2/28

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：US20210381075A1

公开(公告)日：2021-12-09

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 ,  C23G1/00 ,  C23C2/06 ,  C23C2/12 ,  C25D3/22 ,  C25D3/44

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：US20200040420A1

公开(公告)日：2020-02-06

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.