公开(公告)号：US20180023160A1

公开(公告)日：2018-01-25

申请号：US15547100

申请日：2016-01-27

Applicant: JFE STEEL CORPORATION

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

IPC: C21D9/46 ,  C22C38/22 ,  C22C38/28 ,  C22C38/24 ,  C22C38/38 ,  C22C38/16 ,  C22C38/14 ,  C22C38/12 ,  C22C38/60 ,  C22C38/08 ,  C22C38/06 ,  C22C38/04 ,  C22C38/02 ,  C22C38/00 ,  C23C2/06 ,  C23C2/40 ,  C23F17/00 ,  C21D8/02

CPC classification number: C21D9/46 ,  C21D1/25 ,  C21D6/001 ,  C21D6/002 ,  C21D6/005 ,  C21D6/008 ,  C21D8/00 ,  C21D8/005 ,  C21D8/02 ,  C21D8/0205 ,  C21D8/0221 ,  C21D8/0226 ,  C21D8/0236 ,  C21D8/0247 ,  C21D8/0278 ,  C21D8/04 ,  C21D8/0405 ,  C21D8/0421 ,  C21D8/0426 ,  C21D8/0447 ,  C21D8/0473 ,  C21D2211/005 ,  C21D2211/008 ,  C22C38/00 ,  C22C38/001 ,  C22C38/002 ,  C22C38/005 ,  C22C38/008 ,  C22C38/02 ,  C22C38/04 ,  C22C38/06 ,  C22C38/08 ,  C22C38/12 ,  C22C38/14 ,  C22C38/16 ,  C22C38/18 ,  C22C38/22 ,  C22C38/24 ,  C22C38/28 ,  C22C38/38 ,  C22C38/60 ,  C23C2/02 ,  C23C2/06 ,  C23C2/28 ,  C23C2/40 ,  C23F17/00

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：US20170211163A1

公开(公告)日：2017-07-27

申请号：US15326811

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 ,  C21D6/00 ,  C22C38/60 ,  C22C38/38 ,  C22C38/16 ,  C23F17/00 ,  C22C38/12 ,  C22C38/06 ,  C22C38/00 ,  C22C38/04 ,  C22C38/02 ,  C23C2/06 ,  C21D8/02 ,  C22C38/14

CPC classification number: C21D9/46 ,  C21D6/005 ,  C21D6/008 ,  C21D8/0205 ,  C21D8/0226 ,  C21D8/0236 ,  C21D8/0263 ,  C21D8/0278 ,  C21D2211/001 ,  C21D2211/005 ,  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 ,  C23F17/00

Abstract: Disclosed is a high-strength steel sheet having a tensile strength (TS) of 780 MPa or more and excellent in ductility, fatigue properties, balance between high strength and ductility, 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, and 5-20% 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 the retained austenite has a mean free path of 1.2 μm or less.

公开(公告)号：US20160186299A1

公开(公告)日：2016-06-30

申请号：US14909562

申请日：2014-07-16

Applicant: JFE STEEL CORPORATION

Inventor： Hidekazu MINAMI ,  Takeshi YOKOTA ,  Kazuhiro SETO

IPC: C22C38/60 ,  C23C2/06 ,  C22C38/38 ,  C22C38/26 ,  C22C38/24 ,  C22C38/22 ,  C22C38/16 ,  C22C38/12 ,  C22C38/08 ,  C22C38/06 ,  C22C38/04 ,  C22C38/02 ,  C22C38/00 ,  C21D9/46 ,  C21D8/02 ,  C21D6/00 ,  B32B15/01 ,  C23C2/02

CPC classification number: C22C38/60 ,  B21B1/22 ,  B21B3/00 ,  B32B15/01 ,  B32B15/013 ,  C21D6/004 ,  C21D6/005 ,  C21D6/008 ,  C21D8/0205 ,  C21D8/0226 ,  C21D8/0236 ,  C21D8/0247 ,  C21D8/0263 ,  C21D9/46 ,  C21D2211/005 ,  C21D2211/008 ,  C22C38/00 ,  C22C38/001 ,  C22C38/002 ,  C22C38/005 ,  C22C38/008 ,  C22C38/02 ,  C22C38/04 ,  C22C38/06 ,  C22C38/08 ,  C22C38/12 ,  C22C38/16 ,  C22C38/22 ,  C22C38/24 ,  C22C38/26 ,  C22C38/38 ,  C22C38/58 ,  C23C2/02 ,  C23C2/06 ,  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, Nb: 0.001% or more and 0.200% or less, and V: 0.001% or more and 0.200% or less, in which the contents of C, Nb, and V 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 each of 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，Nb：0.001％以上且0.200％以下，V：0.001％以上且0.200％以下，C，Nb，V含量满足式（500＆ ; 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， 铁素体和马氏体中的α-纤维的γ纤维的强度比为1.00以上。

公开(公告)号：US20190093191A1

公开(公告)日：2019-03-28

申请号：US15768894

申请日：2016-10-03

Applicant: JFE STEEL CORPORATION

Inventor： Koichi NAKAGAWA ,  Shinjiro KANEKO ,  Takeshi YOKOTA ,  Kazuhiro SETO

IPC: C21D8/02 ,  C22C38/04 ,  C22C38/06 ,  C22C38/02 ,  C22C38/00 ,  C21D1/18 ,  C23C2/02 ,  C23C2/06 ,  C23C2/12 ,  C23C2/28 ,  C23C2/40

Abstract: A hot pressed member having all of: high strength of 1500 MPa or more in tensile strength TS; high ductility of 6.0% or more in uniform elongation uEl; and excellent heat treatment hardenability of increasing in yield stress YS by 150 MPa or more when subjected to heat treatment (baking finish) is provided. A hot pressed member comprises: a predetermined chemical composition (in particular, low C of 0.090% or more and less than 0.30% and high Mn of 3.5% or more and less than 11.0%); a microstructure including a martensite phase of 70.0% or more in volume fraction and a retained austenite phase of 3.0% or more and 30.0% or less in volume fraction; and a dislocation density of 1.0×1016/m2 or more.

公开(公告)号：US20180305785A1

公开(公告)日：2018-10-25

申请号：US15768905

申请日：2016-10-03

Applicant: JFE STEEL CORPORATION

Inventor： Koichi NAKAGAWA ,  Shinjiro KANEKO ,  Takeshi YOKOTA ,  Kazuhiro SETO

IPC: C21D9/46 ,  B21D22/20 ,  C21D1/18 ,  B21D22/02 ,  C22C38/60 ,  C22C38/58

CPC classification number: C21D9/46 ,  B21D22/02 ,  B21D22/022 ,  B21D22/20 ,  B21D24/00 ,  B21D53/88 ,  C21D1/18 ,  C21D9/00 ,  C21D2211/001 ,  C21D2211/005 ,  C21D2211/008 ,  C22C38/00 ,  C22C38/004 ,  C22C38/58 ,  C22C38/60

Abstract: A hot pressed member comprises: a predetermined chemical composition (in particular, low C of 0.090% or more and less than 0.30% and high Mn of 3.5% or more and less than 11.0%); a first region having: a microstructure including a martensite phase of 80.0% or more in volume fraction and a retained austenite phase of 3.0% or more and 20.0% or less in volume fraction; and a dislocation density of 1.0×1016/m2 or more; and a second region having a microstructure including a ferrite phase of 30.0% or more and 60.0% or less in volume fraction, a retained austenite phase of 10.0% or more and 70.0% or less in volume fraction, and a martensite phase of 30.0% or less in volume fraction.

公开(公告)号：US20170298482A1

公开(公告)日：2017-10-19

申请号：US15516698

申请日：2015-10-29

Applicant: JFE STEEL CORPORATION

Inventor： Yoshiyasu KAWASAKI ,  Hiroshi MATSUDA ,  Takeshi YOKOTA ,  Takako YAMASHITA ,  Kazuhiro SETO

IPC: C22C38/14 ,  B32B15/01 ,  C23C2/40 ,  C23C2/12 ,  C22C38/12 ,  C22C38/06 ,  C22C38/04 ,  C22C38/02 ,  C22C38/00 ,  C21D9/46 ,  C21D8/02 ,  C21D6/00 ,  C21D1/26 ,  C23F17/00 ,  B32B15/18 ,  B32B15/20 ,  C25D3/22

Abstract: Disclosed is a steel sheet having a predetermined chemical composition and a steel microstructure that contains, in area ratio, 15% or more and 55% or less of polygonal ferrite and 15% or more and 30% or less of martensite, and that contains, in volume fraction, 12% or more of retained austenite, in which the polygonal ferrite, the martensite, and the retained austenite have a mean grain size of 4 μm or less, 2 μm or less, and 2 μm or less, respectively, and each have a mean grain aspect ratio of 2.0 or less, and in which a value obtained by dividing an Mn content in the retained austenite in mass % by an Mn content in the polygonal ferrite in mass % equals 2.0 or more.

公开(公告)号：US20170218475A1

公开(公告)日：2017-08-03

申请号：US15500446

申请日：2015-08-05

Applicant: JFE STEEL CORPORATION

Inventor： Yoshiyasu KAWASAKI ,  Hiroshi MATSUDA ,  Takeshi YOKOTA ,  Yoshimasa FUNAKAWA ,  Kazuhiro SETO ,  Yukihiro MATSUBARA

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

CPC classification number: C21D9/46 ,  B32B15/013 ,  C21D1/26 ,  C21D8/0226 ,  C21D8/0236 ,  C21D8/0247 ,  C21D8/0263 ,  C21D8/0278 ,  C21D2211/001 ,  C21D2211/002 ,  C21D2211/005 ,  C22C38/001 ,  C22C38/002 ,  C22C38/005 ,  C22C38/008 ,  C22C38/02 ,  C22C38/04 ,  C22C38/06 ,  C22C38/12 ,  C22C38/14 ,  C22C38/16 ,  C22C38/18 ,  C22C38/38 ,  C22C38/60 ,  C23C2/06 ,  C23C2/28 ,  C23C2/40 ,  C23G1/00

Abstract: Disclosed is a method comprising: preparing a steel slab with a predetermined chemical composition; subjecting the steel slab to hot rolling by heating it to a temperature of 1100-1300° C., hot rolling it with a finisher delivery temperature of 800-1000° C. to form a hot-rolled steel sheet, and coiling the steel sheet at a mean coiling temperature of 200-500° C.; subjecting the steel sheet to pickling treatment; and subjecting the steel sheet to annealing by retaining the steel sheet at a temperature of 740-840° C. for 10-900 s, then cooling the steel sheet at a mean cooling rate of 5-50° C./s to a cooling stop temperature of higher than 350° C. and 550° C. or lower, and retaining the steel sheet in a temperature range of higher than 350° C. to 550° C. for 10 s or more.

公开(公告)号：US20170204491A1

公开(公告)日：2017-07-20

申请号：US15326793

申请日：2015-08-05

Applicant: JFE STEEL CORPORATION

Inventor： Yoshiyasu KAWASAKI ,  Hiroshi MATSUDA ,  Takeshi YOKOTA ,  Yoshimasa FUNAKAWA ,  Kazuhiro SETO ,  Yukihiro MATSUBARA

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

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 ,  C22C38/001 ,  C22C38/002 ,  C22C38/005 ,  C22C38/008 ,  C22C38/02 ,  C22C38/04 ,  C22C38/06 ,  C22C38/12 ,  C22C38/14 ,  C22C38/16 ,  C22C38/18 ,  C22C38/38 ,  C22C38/60 ,  C23C2/02 ,  C23C2/06 ,  C23C2/28 ,  C23F17/00

Abstract: Disclosed is a method comprising: preparing a steel slab with a predetermined chemical composition; subjecting the steel slab to hot rolling by heating it to a temperature of 1100-1300° C., hot rolling it with a finisher delivery temperature of 800-1000° C. to form a hot-rolled steel sheet, and coiling the steel sheet at a mean coiling temperature of 200-500° C.; subjecting the steel sheet to pickling treatment; subjecting the steel sheet to annealing by retaining the steel sheet at a temperature of 740-840° C. for 10-900 s, and the cooling the steel sheet at a mean cooling rate of 5-30° C./s to a cooling stop temperature of 150-350° C.; and subjecting the steel sheet to reheating treatment by reheating the steel sheet to a reheating temperature of higher than 350° C. and 550° C. or lower, and retaining the steel sheet at the reheating temperature for 10 s or more.

公开(公告)号：US20180127847A9

公开(公告)日：2018-05-10

申请号：US15520236

申请日：2015-10-29

Applicant: JFE STEEL CORPORATION

Inventor： Yoshiyasu KAWASAKI ,  Hiroshi MATSUDA ,  Takeshi YOKOTA ,  Takako YAMASHITA ,  Kazuhiro SETO

IPC: C21D9/46 ,  C25D3/22 ,  B32B15/01 ,  C23C2/40 ,  C23C2/12 ,  C22C38/38 ,  C22C38/28 ,  C22C38/16 ,  C22C38/12 ,  C22C38/08 ,  C22C38/02 ,  C22C38/00 ,  C21D8/02 ,  C21D6/00 ,  C23G1/00

CPC classification number: C21D9/46 ,  B32B15/012 ,  B32B2255/06 ,  B32B2255/205 ,  C21D6/001 ,  C21D6/002 ,  C21D6/005 ,  C21D6/008 ,  C21D8/0205 ,  C21D8/0226 ,  C21D8/0263 ,  C21D8/0278 ,  C22C38/00 ,  C22C38/001 ,  C22C38/002 ,  C22C38/008 ,  C22C38/02 ,  C22C38/08 ,  C22C38/12 ,  C22C38/14 ,  C22C38/16 ,  C22C38/28 ,  C22C38/38 ,  C22C38/60 ,  C23C2/02 ,  C23C2/06 ,  C23C2/12 ,  C23C2/28 ,  C23C2/40 ,  C23G1/00 ,  C25D3/22

Abstract: Disclosed is a steel sheet having a predetermined chemical composition and a steel microstructure that contains, in area ratio, 35% or more and 80% or less of polygonal ferrite and 5% or more and 25% or less of martensite, and that contains, in volume fraction, 8% or more of retained austenite, in which the polygonal ferrite, the martensite, and the retained austenite have a mean grain size of 6 μm or less, 3 μm or less, and 3 μm or less, respectively, and each have a mean grain aspect ratio of 2.0 or less, and in which a value obtained by dividing an Mn content in the retained austenite in mass % by an Mn content in the polygonal ferrite in mass % equals 2.0 or more.

公开(公告)号：US20180127846A9

公开(公告)日：2018-05-10

申请号：US15517467

申请日：2015-10-29

Applicant: JFE STEEL CORPORATION

Inventor： Yoshiyasu KAWASAKI ,  Hiroshi MATSUDA ,  Takako YAMASHITA ,  Takeshi YOKOTA ,  Kazuhiro SETO

IPC: C21D9/46 ,  C25D3/22 ,  C21D8/02 ,  C22C38/28 ,  C22C38/16 ,  C22C38/14 ,  C22C38/12 ,  C22C38/08 ,  C22C38/06 ,  C22C38/04 ,  C22C38/02 ,  C22C38/00 ,  C22C38/60

CPC classification number: C21D9/46 ,  C21D8/0205 ,  C21D8/0226 ,  C21D8/0236 ,  C21D8/0278 ,  C22C38/00 ,  C22C38/001 ,  C22C38/002 ,  C22C38/005 ,  C22C38/008 ,  C22C38/02 ,  C22C38/04 ,  C22C38/06 ,  C22C38/08 ,  C22C38/12 ,  C22C38/14 ,  C22C38/16 ,  C22C38/28 ,  C22C38/60 ,  C23C2/02 ,  C23C2/06 ,  C23C2/12 ,  C23C2/28 ,  C25D3/22

Abstract: A high-strength steel sheet with excellent formability and high yield ratio that has TS of 590 MPa or more and YR of 68% or more is obtained by providing a predetermined chemical composition and a steel microstructure that contains, in area ratio, 35 to 80% of polygonal ferrite, 5% or more of non-recrystallized ferrite, and 5 to 25% of martensite, and that contains, in volume fraction, 8% or more of retained austenite, in which the polygonal ferrite has a mean grain size of 6 μm or less, the martensite has a mean grain size of 3 μm or less, the retained austenite has a mean grain size of 3 μm or less, and a value obtained by dividing an Mn content in the retained austenite (in mass %) by an Mn content in the polygonal ferrite (in mass %) equals 2.0 or more.