公开(公告)号：US20170204492A1

公开(公告)日：2017-07-20

申请号：US15329026

申请日：2015-07-31

Applicant: JFE STEEL CORPORATION

Inventor： Keiji UEDA ,  Shinjiro KANEKO ,  Masami IWASAKI ,  Reiko SUGIHARA ,  Takeshi YOKOTA ,  Kazuhiro SETO

IPC: C21D9/46 ,  C21D1/26 ,  C22C38/58 ,  C22C38/50 ,  C22C38/48 ,  C22C38/42 ,  C22C38/38 ,  C22C38/28 ,  C22C38/26 ,  C22C38/22 ,  C22C38/20 ,  C22C38/24 ,  C22C38/06 ,  C22C38/02 ,  C22C38/00 ,  C21D8/02

CPC classification number: C21D9/46 ,  C21D1/26 ,  C21D8/0205 ,  C21D8/0226 ,  C21D8/0236 ,  C21D8/0263 ,  C22C38/00 ,  C22C38/001 ,  C22C38/002 ,  C22C38/02 ,  C22C38/06 ,  C22C38/20 ,  C22C38/22 ,  C22C38/24 ,  C22C38/26 ,  C22C38/28 ,  C22C38/38 ,  C22C38/42 ,  C22C38/48 ,  C22C38/50 ,  C22C38/58

Abstract: A cold-rolled steel sheet having excellent spot weldability suitable for use in vehicles, electric appliances, etc. is provided. The cold-rolled steel sheet has a steel composition containing, in mass%: C: 0.05% to 0.13%; Si: 0.05% to 2.0%; Mn: 1.5% to 4.0%; P: 0.05% or less; S: 0.005% or less; Al: 0.01% to 0.10%; Cr: 0.05% to 1.0%; Nb: 0.010% to 0.070%; Ti: 0.005% to 0.040%; and N: 0.0005% to 0.0065%, with a mass ratio Ti/N of Ti and N being 2.5 or more and 7.5 or less, and a balance being Fe and incidental impurities, wherein 70 mass % or more of Ti in steel exists as a precipitate, and 15 mass % or more of Nb in the steel exists as solute Nb, and a tensile strength is 980 MPa or more.

公开(公告)号：US20170175219A1

公开(公告)日：2017-06-22

申请号：US15327126

申请日：2015-08-05

Applicant: JFE STEEL CORPORATION

Inventor： Yoshiyasu KAWASAKI ,  Hiroshi MATSUDA ,  Yoshie OBATA ,  Shinjiro KANEKO ,  Takeshi YOKOTA ,  Kazuhiro SETO

IPC: C21D9/46 ,  C22C38/38 ,  C22C38/60 ,  C22C38/32 ,  C22C38/06 ,  C22C38/04 ,  C22C38/02 ,  C22C38/00 ,  C22C38/14 ,  C22C38/12 ,  C21D8/02 ,  C22C38/28

Abstract: Disclosed is a high-strength steel sheet having a predetermined chemical composition, satisfying the condition that Mn content divided by B content equals 2100 or less, and a steel microstructure that contains, by area, 25-80% of ferrite and bainitic ferrite in total, 3-20% of martensite, and that contains, by volume, 10% or more of retained austenite, in which the retained austenite has a mean grain size of 2 μm or less, a mean Mn content in the retained austenite in mass % is at least 1.2 times the Mn content in the steel sheet in mass %, and an aggregate of retained austenite formed by seven or more identically-oriented retained austenite grains accounts for 60% or more by area of the entire retained austenite.

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：US20180179610A9

公开(公告)日：2018-06-28

申请号：US15547876

申请日：2016-01-27

Applicant: JFE STEEL CORPORATION

Inventor： Hidekazu MINAMI ,  Shinjiro KANEKO ,  Takeshi YOKOTA ,  Kazuhiro SETO

IPC: C21D9/46 ,  C23C2/28 ,  C23C2/06 ,  C22C38/12 ,  C22C38/06 ,  C22C38/04 ,  C22C38/02 ,  B32B15/01 ,  C22C38/00 ,  C21D8/02 ,  C21D6/00

CPC classification number: C21D9/46 ,  B32B15/013 ,  C21D6/005 ,  C21D6/008 ,  C21D8/0205 ,  C21D8/0226 ,  C21D8/0236 ,  C21D8/0273 ,  C21D2211/005 ,  C21D2211/008 ,  C22C38/00 ,  C22C38/001 ,  C22C38/002 ,  C22C38/02 ,  C22C38/04 ,  C22C38/06 ,  C22C38/12 ,  C22C38/60 ,  C23C2/02 ,  C23C2/06 ,  C23C2/28

Abstract: A steel sheet has a microstructure that contains ferrite in an area ratio of 20% or more, martensite in an area ratio of 5% or more, and tempered martensite in an area ratio of 5% or more. The ferrite has a mean grain size of 20.0 μm or less. An inverse intensity ratio of γ-fiber to α-fiber in the ferrite is 1.00 or more and an inverse intensity ratio of γ-fiber to α-fiber in the martensite and the tempered martensite is 1.00 or more.

公开(公告)号：US20180016656A1

公开(公告)日：2018-01-18

申请号：US15547876

申请日：2016-01-27

Applicant: JFE STEEL CORPORATION

Inventor： Hidekazu MINAMI ,  Shinjiro KANEKO ,  Takeshi YOKOTA ,  Kazuhiro SETO

IPC: C21D9/46 ,  C23C2/06 ,  C22C38/12 ,  C22C38/06 ,  C21D6/00 ,  C22C38/02 ,  B32B15/01 ,  C22C38/00 ,  C21D8/02 ,  C23C2/28 ,  C22C38/04

CPC classification number: C21D9/46 ,  B32B15/013 ,  C21D1/25 ,  C21D6/005 ,  C21D6/008 ,  C21D8/0205 ,  C21D8/0226 ,  C21D8/0236 ,  C21D8/0273 ,  C21D2211/005 ,  C21D2211/008 ,  C22C38/00 ,  C22C38/001 ,  C22C38/002 ,  C22C38/02 ,  C22C38/04 ,  C22C38/06 ,  C22C38/12 ,  C22C38/60 ,  C23C2/02 ,  C23C2/06 ,  C23C2/28

Abstract: A steel sheet has a microstructure that contains ferrite in an area ratio of 20% or more, martensite in an area ratio of 5% or more, and tempered martensite in an area ratio of 5% or more. The ferrite has a mean grain size of 20.0 μm or less. An inverse intensity ratio of γ-fiber to α-fiber in the ferrite is 1.00 or more and an inverse intensity ratio of γ-fiber to α-fiber in the martensite and the tempered martensite is 1.00 or more.

公开(公告)号：US20170306437A1

公开(公告)日：2017-10-26

申请号：US15521515

申请日：2015-10-05

Applicant: JFE STEEL CORPORATION

Inventor： Koichi NAKAGAWA ,  Takeshi YOKOTA ,  Kazuhiro SETO

IPC: C21D9/46 ,  B21D22/02 ,  C23C2/12 ,  C23C2/06 ,  C22C38/38 ,  C22C38/14 ,  C22C38/12 ,  C22C38/08 ,  C22C38/06 ,  C22C38/02 ,  C22C38/00 ,  C22C18/00 ,  C23C2/28 ,  B32B15/01 ,  C21D1/673 ,  C21D8/02 ,  C21D6/00 ,  C23C2/40

CPC classification number: C21D9/46 ,  B21D22/022 ,  B32B15/012 ,  B32B15/013 ,  B32B2255/06 ,  B32B2255/205 ,  C21D1/18 ,  C21D1/673 ,  C21D6/001 ,  C21D6/002 ,  C21D6/005 ,  C21D6/008 ,  C21D8/0205 ,  C21D8/0226 ,  C21D8/0236 ,  C21D8/0278 ,  C21D8/0436 ,  C21D9/48 ,  C21D2211/001 ,  C21D2211/008 ,  C22C18/00 ,  C22C38/00 ,  C22C38/001 ,  C22C38/002 ,  C22C38/005 ,  C22C38/02 ,  C22C38/04 ,  C22C38/06 ,  C22C38/08 ,  C22C38/12 ,  C22C38/14 ,  C22C38/38 ,  C22C38/60 ,  C23C2/06 ,  C23C2/12 ,  C23C2/28 ,  C23C2/40 ,  Y10T428/12757

Abstract: A high-strength hot-pressed part having a specified chemical composition, a microstructure including, in terms of volume fraction, 80% or more of a martensite phase, in a range of 3.0% to 20.0% of a retained austenite phase, a tensile strength TS of 1500 MPa or more, and a uniform elongation uEl of 6.0% or more. A method for manufacturing the high-strength hot-pressed part, the method comprising performing a heating process and a hot press forming process on a raw material steel sheet in order to obtain a hot-pressed part having a specified shape.

公开(公告)号：US20170218472A1

公开(公告)日：2017-08-03

申请号：US15326116

申请日：2015-08-05

Applicant: JFE STEEL CORPORATION

Inventor： Yoshiyasu KAWASAKI ,  Hiroshi MATSUDA ,  Kazunori TAHARA ,  Takeshi YOKOTA ,  Kaneharu OKUDA ,  Kazuhiro SETO

IPC: C21D9/46 ,  C23C2/28 ,  C23C2/40 ,  C22C38/60 ,  C22C38/38 ,  C22C38/16 ,  C22C38/14 ,  C22C38/12 ,  C22C38/06 ,  C22C38/04 ,  C22C38/02 ,  C22C38/00 ,  C21D8/02 ,  C21D1/60 ,  C23G1/00 ,  B32B15/01 ,  C23C2/06

CPC classification number: C21D9/46 ,  B32B15/013 ,  C21D1/60 ,  C21D8/0226 ,  C21D8/0236 ,  C21D8/0263 ,  C21D8/0278 ,  C21D2211/001 ,  C21D2211/002 ,  C21D2211/005 ,  C21D2211/008 ,  C22C38/00 ,  C22C38/001 ,  C22C38/002 ,  C22C38/005 ,  C22C38/008 ,  C22C38/02 ,  C22C38/04 ,  C22C38/06 ,  C22C38/12 ,  C22C38/14 ,  C22C38/16 ,  C22C38/38 ,  C22C38/60 ,  C23C2/06 ,  C23C2/28 ,  C23C2/40 ,  C23G1/00

Abstract: Disclosed is a high-strength steel sheet having a tensile strength (TS) of 780 MPa or more and excellent in ductility, fatigue properties, stretch flangeability, surface characteristics, and sheet passage ability that can be obtained by providing a predetermined chemical composition and a steel microstructure that contains, by area, 20-50% of ferrite, 5-25% of bainitic ferrite, 1-10% of martensite, and 5-15% of tempered martensite, and that contains, by volume, 10% or more of retained austenite, in which the retained austenite has a mean grain size of 2 μm or less, a mean Mn content in the retained austenite in mass % is at least 1.2 times the Mn content in the steel sheet in mass %, the retained austenite has a mean free path of 1.2 μm or less, and the tempered martensite has a mean free path of 1.2 μm or less.

公开(公告)号：US20170204490A1

公开(公告)日：2017-07-20

申请号：US15326540

申请日：2015-08-05

Applicant: JFE STEEL CORPORATION

Inventor： Yoshiyasu KAWASAKI ,  Hiroshi MATSUDA ,  Yoshie OBATA ,  Shinjiro KANEKO ,  Takeshi YOKOTA ,  Kazuhiro SETO

IPC: C21D9/46 ,  C21D6/00 ,  C22C38/60 ,  C22C38/38 ,  C23F17/00 ,  C22C38/14 ,  C22C38/12 ,  C22C38/06 ,  C22C38/00 ,  C23C2/06 ,  C21D8/02 ,  C22C38/16

CPC classification number: C21D9/46 ,  C21D6/005 ,  C21D6/008 ,  C21D8/0205 ,  C21D8/0226 ,  C21D8/0236 ,  C21D8/0263 ,  C21D8/0273 ,  C21D8/0278 ,  C21D2211/001 ,  C21D2211/002 ,  C21D2211/005 ,  C21D2211/008 ,  C22C18/04 ,  C22C38/00 ,  C22C38/001 ,  C22C38/002 ,  C22C38/005 ,  C22C38/008 ,  C22C38/02 ,  C22C38/04 ,  C22C38/06 ,  C22C38/12 ,  C22C38/14 ,  C22C38/16 ,  C22C38/38 ,  C22C38/60 ,  C23C2/02 ,  C23C2/06 ,  C23F17/00

Abstract: Disclosed is a high-strength steel sheet having a predetermined chemical composition and a steel microstructure that contains, by area, 25-80% of ferrite and bainitic ferrite in total, and 3-20% of martensite, and that contains, by volume, 10% or more of retained austenite, in which the retained austenite has a mean grain size of 2 μm or less, a mean Mn content in the retained austenite in mass % is at least 1.2 times the Mn content in the steel sheet in mass %, an area ratio of retained austenite having a mean C content in mass % at least 2.1 times the C content in the steel sheet in mass % is 60% or more of an area ratio of the entire retained austenite.

公开(公告)号：US20190323101A1

公开(公告)日：2019-10-24

申请号：US16453194

申请日：2019-06-26

Applicant: JFE STEEL CORPORATION

Inventor： Hidekazu MINAMI ,  Takeshi YOKOTA ,  Kazuhiro SETO

IPC: C21D9/46 ,  C21D6/00 ,  C23C2/02 ,  C21D8/02 ,  C22C38/22 ,  C22C38/26 ,  C22C38/28 ,  C23C2/40 ,  C23C2/06 ,  C22C38/60 ,  C22C38/38 ,  C22C38/34 ,  C22C38/18 ,  C22C38/16 ,  C22C38/12 ,  C22C38/08 ,  C22C38/06 ,  C22C38/04 ,  C22C38/02 ,  C22C38/00 ,  B32B15/01 ,  C22C38/14 ,  C22C18/00 ,  C23C2/28

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.

公开(公告)号：US20180195143A1

公开(公告)日：2018-07-12

申请号：US15742116

申请日：2016-08-26

Applicant: JFE STEEL CORPORATION

Inventor： Fusae SHIIMORI ,  Yoshiyasu KAWASAKI ,  Shinjiro KANEKO ,  Takeshi YOKOTA ,  Kazuhiro SETO ,  Takaaki TANAKA ,  Yuki TOJI

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

CPC classification number: C21D9/46 ,  B32B15/013 ,  C21D1/32 ,  C21D2211/001 ,  C21D2211/002 ,  C21D2211/005 ,  C22C18/04 ,  C22C38/00 ,  C22C38/001 ,  C22C38/002 ,  C22C38/005 ,  C22C38/02 ,  C22C38/04 ,  C22C38/06 ,  C22C38/08 ,  C22C38/12 ,  C22C38/14 ,  C22C38/16 ,  C22C38/18 ,  C22C38/38 ,  C23C2/06

Abstract: This disclosure provides a high-strength thin steel sheet excellent in both tensile strength and elongation with small elongation anisotropy. The high-strength thin steel sheet has a specific chemical composition and a microstructure where a total area ratio of ferrite, tempered bainitic ferrite and bainitic ferrite is 40% or more and 70% or less, an area ratio of martensite is 5% or more and 30% or less, an area ratio of retained austenite is 10% or more and 35% or less, an average equivalent circular diameter of martensite and retained austenite (secondary phase) grains is 2.0 μm or less, an area ratio of secondary phase grains having an equivalent circular diameter of 2.0 μm or more is 10% or less, and an average minor axis length of secondary phase grains is 0.40 μm or less.