公开(公告)号：US20190003006A1

公开(公告)日：2019-01-03

申请号：US16064526

申请日：2016-12-08

Applicant: JFE Steel Corporation

Inventor： Satoshi Maeda ,  Yoichi Makimizu ,  Yoshitsugu Suzuki ,  Katsumi Yamada ,  Yoshiyasu Kawasaki

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

Abstract: High-strength galvannealed steel sheet including any of a) an oxide containing Fe and Mn, b) an oxide containing Fe and Mn and an Fe oxide, c) an oxide containing Fe and Mn and a Mn oxide, d) an oxide containing Fe and Mn, an Fe oxide, and a Mn oxide, and e) an Fe oxide and a Mn oxide is present in a zinc coated layer. The total amount of oxide is 0.01 to 0.100 g/m2; the ratio by mass % of Mn to Fe, e.g., Mn/Fe, contained in the oxide is 0.10 to 10.00; an oxide of at least one selected from Fe and Mn is present in an amount of 60% or more; and an oxide of at least one selected from Fe and Mn is present in a surface layer portion of a steel sheet in an amount of 0.040 g/m2 or less (not including zero).

公开(公告)号：US11136641B2

公开(公告)日：2021-10-05

申请号：US16064526

申请日：2016-12-08

Applicant: JFE Steel Corporation

Inventor： Satoshi Maeda ,  Yoichi Makimizu ,  Yoshitsugu Suzuki ,  Katsumi Yamada ,  Yoshiyasu Kawasaki

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

Abstract: High-strength galvannealed steel sheet including any of a) an oxide containing Fe and Mn, b) an oxide containing Fe and Mn and an Fe oxide, c) an oxide containing Fe and Mn and a Mn oxide, d) an oxide containing Fe and Mn, an Fe oxide, and a Mn oxide, and e) an Fe oxide and a Mn oxide is present in a zinc coated layer. The total amount of oxide is 0.01 to 0.100 g/m2; the ratio by mass % of Mn to Fe, e.g., Mn/Fe, contained in the oxide is 0.10 to 10.00; an oxide of at least one selected from Fe and Mn is present in an amount of 60% or more; and an oxide of at least one selected from Fe and Mn is present in a surface layer portion of a steel sheet in an amount of 0.040 g/m2 or less (not including zero).

公开(公告)号：US20210010100A1

公开(公告)日：2021-01-14

申请号：US17041567

申请日：2019-03-26

Applicant: JFE Steel Corporation

Inventor： Satoshi Maeda ,  Yoshiyasu Kawasaki ,  Yusuke Fushiwaki ,  Mai Aoyama

IPC: C21D9/46 ,  C23C2/06 ,  C23C2/28 ,  C23C2/40 ,  C22C38/02 ,  C22C38/04 ,  C22C38/06 ,  C22C38/00 ,  C22C38/08 ,  C22C38/12 ,  C22C38/14 ,  C22C38/16 ,  C22C38/32 ,  C22C38/60 ,  C21D8/02

Abstract: A method for producing a high-strength hot-dip galvannealed steel sheet, in which a high-strength steel sheet is used as a base material, includes a rolling step (x) of rolling a hot-dip galvannealed steel sheet with a coating layer having an Fe concentration of 8% to 17% by mass, and a heat treatment step (y) of heating the coated steel sheet which has been subjected to the rolling step (x) under the conditions satisfying the following formulae (1) and (2): (273+T)×(20+2×log10(t))≥8000   (1) 40≤T≤160   (2) where T: heating temperature (° C.) of the coated steel sheet, and t: holding time (hr) at the heating temperature T.

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：US20200308664A1

公开(公告)日：2020-10-01

申请号：US16310951

申请日：2017-06-05

Applicant: JFE Steel Corporation

Inventor： Satoshi Maeda ,  Yoichi Makimizu ,  Yoshitsugu Suzuki ,  Yoshiyasu Kawasaki

IPC: C21D9/46 ,  C22C38/38 ,  C22C38/16 ,  C22C38/14 ,  C22C38/12 ,  C22C38/08 ,  C22C38/06 ,  C22C38/02 ,  C22C38/00 ,  C21D8/02 ,  C21D6/00 ,  B32B15/01 ,  C23C2/06 ,  C23C2/28 ,  C23C2/40

Abstract: Provided are a high-strength galvannealed steel sheet, and a manufacturing method therefor. The manufacturing method is for a high-strength galvannealed steel sheet which includes a zinc coated layer with a coating weight of 20 to 120 g/m2 per side on a surface of a steel sheet having a chemical composition containing, in mass %, C: 0.03 to 0.35%, Si: 0.01 to 1.00%, Mn: 3.6 to 8.0%, Al: 0.001 to 1.00%, P: 0.100% or less, and S: 0.010% or less, with the balance being Fe and inevitable impurities. The method includes: setting a cold rolling reduction ratio to 20% or more and 35% or less when cold rolling is performed on the steel sheet, and setting a maximum steel sheet temperature to be reached in an annealing furnace to 600° C. or higher and 700° C. or lower when annealing is further performed on the steel sheet.

公开(公告)号：US11643702B2

公开(公告)日：2023-05-09

申请号：US17491639

申请日：2021-10-01

Applicant: JFE Steel Corporation

Inventor： Satoshi Maeda ,  Yoshiyasu Kawasaki ,  Yusuke Fushiwaki ,  Mai Aoyama

IPC: C21D9/46 ,  C21D8/02 ,  C22C38/00 ,  C22C38/02 ,  C22C38/04 ,  C22C38/06 ,  C22C38/08 ,  C22C38/12 ,  C22C38/14 ,  C22C38/16 ,  C22C38/32 ,  C22C38/60 ,  C23C2/06 ,  C23C2/28 ,  C23C2/40 ,  C21D6/00

CPC classification number: C21D9/46 ,  C21D6/00 ,  C21D6/005 ,  C21D6/008 ,  C21D8/0205 ,  C21D8/0226 ,  C21D8/0247 ,  C21D8/0263 ,  C21D8/0273 ,  C22C38/002 ,  C22C38/02 ,  C22C38/04 ,  C22C38/06 ,  C22C38/08 ,  C22C38/12 ,  C22C38/14 ,  C22C38/16 ,  C22C38/32 ,  C22C38/60 ,  C23C2/06 ,  C23C2/28 ,  C23C2/40

Abstract: A method for producing a high-strength hot-dip galvannealed steel sheet, in which a high-strength steel sheet is used as a base material, includes a rolling step (x) of rolling a hot-dip galvannealed steel sheet with a coating layer having an Fe concentration of 8% to 17% by mass, and a heat treatment step (y) of heating the coated steel sheet which has been subjected to the rolling step (x) under the conditions satisfying the following formulae (1) and (2):

(273+T)×(20+2×log10(t))≥8000  (1)

40≤T≤160  (2)



where T: heating temperature (° C.) of the coated steel sheet, and t: holding time (hr) at the heating temperature T.

公开(公告)号：US11597983B2

公开(公告)日：2023-03-07

申请号：US17041567

申请日：2019-03-26

Applicant: JFE Steel Corporation

Inventor： Satoshi Maeda ,  Yoshiyasu Kawasaki ,  Yusuke Fushiwaki ,  Mai Aoyama

IPC: C21D9/46 ,  C23C2/06 ,  C23C2/28 ,  C23C2/40 ,  C22C38/02 ,  C22C38/04 ,  C22C38/06 ,  C22C38/00 ,  C22C38/08 ,  C22C38/12 ,  C22C38/14 ,  C22C38/16 ,  C22C38/32 ,  C22C38/60 ,  C21D8/02 ,  C21D6/00

Abstract: A method for producing a high-strength hot-dip galvannealed steel sheet, in which a high-strength steel sheet is used as a base material, includes a rolling step (x) of rolling a hot-dip galvannealed steel sheet with a coating layer having an Fe concentration of 8% to 17% by mass, and a heat treatment step (y) of heating the coated steel sheet which has been subjected to the rolling step (x) under the conditions satisfying the following formulae (1) and (2): (273+T)×(20+2×log10(t))≥8000  (1) 40≤T≤160  (2) where T: heating temperature (° C.) of the coated steel sheet, and t: holding time (hr) at the heating temperature T.

公开(公告)号：US11384407B2

公开(公告)日：2022-07-12

申请号：US16310951

申请日：2017-06-05

Applicant: JFE Steel Corporation

Inventor： Satoshi Maeda ,  Yoichi Makimizu ,  Yoshitsugu Suzuki ,  Yoshiyasu Kawasaki

IPC: B32B15/01 ,  C22C38/38 ,  C22C38/16 ,  C22C38/14 ,  C22C38/12 ,  C22C38/08 ,  C22C38/06 ,  C22C38/02 ,  C22C38/00 ,  C23C2/06 ,  C23C2/28 ,  C23C2/40 ,  C21D6/00 ,  C21D8/02 ,  C21D9/46 ,  C22C38/04 ,  C22C38/32 ,  C22C38/60 ,  B32B15/04 ,  C22C38/54 ,  C22C38/28 ,  C22C38/50 ,  C23C2/02 ,  C22C38/24 ,  C22C38/58 ,  C23C28/02 ,  C22C38/26 ,  C22C38/48 ,  C22C38/40 ,  C22C38/22 ,  C22C38/44 ,  C23C30/00 ,  C22C38/20 ,  C22C38/18 ,  C22C38/46 ,  B32B15/18 ,  C22C38/42

Abstract: Provided are a high-strength galvannealed steel sheet, and a manufacturing method therefor. The manufacturing method is for a high-strength galvannealed steel sheet which includes a zinc coated layer with a coating weight of 20 to 120 g/m2 per side on a surface of a steel sheet having a chemical composition containing, in mass %, C: 0.03 to 0.35%, Si: 0.01 to 1.00%, Mn: 3.6 to 8.0%, Al: 0.001 to 1.00%, P: 0.100% or less, and S: 0.010% or less, with the balance being Fe and inevitable impurities. The method includes: setting a cold rolling reduction ratio to 20% or more and 35% or less when cold rolling is performed on the steel sheet, and setting a maximum steel sheet temperature to be reached in an annealing furnace to 600° C. or higher and 700° C. or lower when annealing is further performed on the steel sheet.

公开(公告)号：US20220017986A1

公开(公告)日：2022-01-20

申请号：US17491639

申请日：2021-10-01

Applicant: JFE Steel Corporation

Inventor： Satoshi Maeda ,  Yoshiyasu Kawasaki ,  Yusuke Fushiwaki ,  Mai Aoyama

IPC: C21D9/46 ,  C21D8/02 ,  C22C38/00 ,  C22C38/02 ,  C22C38/04 ,  C22C38/06 ,  C22C38/08 ,  C22C38/12 ,  C22C38/14 ,  C22C38/16 ,  C22C38/32 ,  C22C38/60 ,  C23C2/06 ,  C23C2/28 ,  C23C2/40

Abstract: A method for producing a high-strength hot-dip galvannealed steel sheet, in which a high-strength steel sheet is used as a base material, includes a rolling step (x) of rolling a hot-dip galvannealed steel sheet with a coating layer having an Fe concentration of 8% to 17% by mass, and a heat treatment step (y) of heating the coated steel sheet which has been subjected to the rolling step (x) under the conditions satisfying the following formulae (1) and (2): (273+T)×(20+2×log10(t))≥8000  (1) 40≤T≤160  (2) where T: heating temperature (° C.) of the coated steel sheet, and t: holding time (hr) at the heating temperature T.