公开(公告)号：US11136643B2

公开(公告)日：2021-10-05

申请号：US16320864

申请日：2017-08-10

Applicant: JFE STEEL CORPORATION

Inventor： Katsutoshi Takashima ,  Koichi Taniguchi ,  Takashi Kobayashi ,  Hiroshi Matsuda ,  Rinsei Ikeda

IPC: C21D9/46 ,  C21D8/02 ,  C22C38/38 ,  C22C38/12 ,  C22C38/08 ,  C22C38/22 ,  C22C38/00 ,  C22C38/26 ,  C22C38/24 ,  C22C38/28 ,  C22C38/14 ,  C22C38/32 ,  C22C38/06 ,  C22C38/04 ,  C22C38/02 ,  C23C2/02 ,  C23C2/06 ,  C23C2/28 ,  C21D6/00 ,  C21D1/30 ,  C22C38/20 ,  C22C38/58

Abstract: A high-strength steel sheet having a specified chemical composition and a method for producing the same. The steel sheet including a multi-phase structure including, by volume fraction, ferrite of 35% to 65%, residual austenite of 7% or less (including 0%), martensite of 20% to 60%, bainite of 20% or less (including 0%), the ferrite having an average crystal grain size of 8 μm or less and an average aspect ratio of 3.5 or less, the martensite having an average crystal grain size of 3 μm or less, and the bainite having an average crystal grain size of 3 μm or less when contained. A standard deviation of Vickers hardness of the steel sheet being 30 or less when measured at 200 μm intervals from a position of 100 μm from a surface to a central portion in a thickness direction of the sheet.

公开(公告)号：US20210260685A1

公开(公告)日：2021-08-26

申请号：US17319134

申请日：2021-05-13

Applicant: JFE Steel Corporation

Inventor： Hiroshi Matsuda ,  Yasuaki Okita ,  Muneo Matsushita ,  Rinsei Ikeda ,  Kenji Oi

IPC: B23K11/16 ,  B23K11/11 ,  C22C38/60 ,  B23K11/34 ,  C22C38/00 ,  B32B15/04 ,  C22C38/02 ,  C22C38/04 ,  C22C38/06 ,  C22C38/18

Abstract: A welding process used in a method of manufacturing a steel sheet assembly includes spot welding steel sheets performed for a heat time of 0.08 seconds or more using a convex electrode with a tip radius of curvature of 20 mm or more or a flat electrode such that the weld force F (kN) for initial 0.03 seconds of the heat time satisfies formula: F

公开(公告)号：US10066286B2

公开(公告)日：2018-09-04

申请号：US14761707

申请日：2014-02-18

Applicant: JFE STEEL CORPORATION

Inventor： Hiroshi Matsuda ,  Hideyuki Takahashi ,  Hiroi Yamaguchi ,  Yasuyuki Hayakawa ,  Takashi Terashima ,  Yuiko Wakisaka

IPC: C23C8/38 ,  C21D8/12 ,  C21D9/46 ,  H01F1/16 ,  C23C8/02 ,  C22C38/02 ,  C23C8/26 ,  H01F1/147 ,  C21D1/773 ,  C21D1/09

CPC classification number: C23C8/38 ,  C21D1/09 ,  C21D1/773 ,  C21D8/12 ,  C21D8/1255 ,  C21D9/46 ,  C21D2201/05 ,  C22C38/02 ,  C23C8/02 ,  C23C8/26 ,  H01F1/14775 ,  H01F1/16

Abstract: Provided is an apparatus for continuously nitriding a strip continuously being fed after cold rolling and before secondary recrystallization annealing in a production line of a grain-oriented electrical steel sheet, comprising: a nitriding zone for nitriding the strip; a cooling zone for cooling the strip; and an optional heating zone provided upstream of the nitriding zone for heating the strip, wherein, the nitriding zone is provided with glow discharge electrodes, and by plasma nitriding the strip by glow discharge with the glow discharge electrodes functioning as positive electrodes and the strip functioning as a negative electrode, inhibitor forming elements are uniformly dispersed over the full length and full width of the strip and a grain-oriented electrical steel sheet with excellent magnetic properties with no variation is obtained.

公开(公告)号：US09644247B2

公开(公告)日：2017-05-09

申请号：US14100438

申请日：2013-12-09

Applicant: JFE Steel Corporation

Inventor： Hiroshi Matsuda ,  Yoshimasa Funakawa ,  Yasushi Tanaka

IPC: C21D8/00 ,  C21D7/13 ,  C21D8/02 ,  C21D1/22 ,  C21D9/46 ,  C22C38/00 ,  C22C38/02 ,  C22C38/04 ,  C22C38/06

CPC classification number: C21D8/0247 ,  C21D1/22 ,  C21D8/0205 ,  C21D9/46 ,  C21D2211/001 ,  C21D2211/002 ,  C21D2211/008 ,  C22C38/001 ,  C22C38/02 ,  C22C38/04 ,  C22C38/06

Abstract: A method for manufacturing a high strength press-formed member includes preparing a steel sheet having the composition including by mass %: C: 0.12% to 0.69%, Si: 3.0% or less, Mn: 0.5% to 3.0%, P: 0.1% or less, S: 0.07% or less, Al: 3.0% or less, N: 0.010% or less, Si+Al: at least 0.7%, and remainder as Fe and incidental impurities, heating the steel sheet to a temperature of 750° C. to 1000° C. and retaining the steel sheet in that state for 5 seconds to 1000 seconds; subjecting the steel sheet to hot press-forming at a temperature of 350° C. to 900° C.; cooling the steel sheet to a temperature of 50° C. to 350° C.; heating the steel sheet to a temperature in a temperature region of 350° C. to 490° C.; and retaining the steel sheet at temperature in the temperature region for 5 seconds to 1000 seconds.

公开(公告)号：US08876987B2

公开(公告)日：2014-11-04

申请号：US14349234

申请日：2012-10-02

Applicant: JFE Steel Corporation

Inventor： Hiroshi Matsuda ,  Yoshimasa Funakawa ,  Kaneharu Okuda ,  Kazuhiro Seto

IPC: C22C38/04 ,  C22C38/06 ,  C22C38/02 ,  C21D8/02 ,  C22C38/00 ,  C22C38/12 ,  C22C38/14 ,  C23C2/02 ,  C22C38/28 ,  C22C38/38 ,  C22C38/32 ,  C22C38/16 ,  C22C38/08

CPC classification number: C21D8/0263 ,  C21D6/008 ,  C21D8/02 ,  C21D8/0226 ,  C21D8/0236 ,  C21D9/46 ,  C21D2211/001 ,  C21D2211/002 ,  C21D2211/005 ,  C21D2211/008 ,  C22C38/001 ,  C22C38/002 ,  C22C38/005 ,  C22C38/02 ,  C22C38/04 ,  C22C38/06 ,  C22C38/08 ,  C22C38/12 ,  C22C38/14 ,  C22C38/16 ,  C22C38/28 ,  C22C38/32 ,  C22C38/38 ,  C22C38/60 ,  C23C2/02 ,  C23C2/06 ,  C23C2/28 ,  C23C2/40 ,  Y10S148/909 ,  Y10T428/12799

Abstract: A high strength pressed member has excellent ductility and stretch flangeability and tensile strength of 780-1400 MPa, with a predetermined steel composition and steel microstructure relative to the entire microstructure of steel sheet, where area ratio of martensite 5-70%, area ratio of retained austenite 5-40%, area ratio of bainitic ferrite in upper bainite 5% or more, and total thereof is 40% or more, 25% or more of martensite is tempered martensite, polygonal ferrite area ratio is above 10% and below 50% to the entire microstructure of steel sheet, and average grain size is 8 μm or less, average diameter of a group of polygonal ferrite grains is 15 μm or less, the group of polygonal ferrite grains represented by a group of ferrite grains of adjacent polygonal ferrite grains, and average carbon content in retained austenite is 0.70 mass % or more and tensile strength is 780 MPa or more.

Abstract translation: 高强度压制构件具有优异的延展性和拉伸凸缘性和拉伸强度为780-1400MPa，具有预定的钢组成和钢组织相对于钢板的整个微观结构，其中马氏体的面积比为5-70％，面积比为 残留奥氏体5-40％，贝氏体铁素体在上贝氏体中的面积率为5％以上，总计为40％以上，25％以上的马氏体回火马氏体，多边形铁素体面积率在10％以下且低于50 ％的平均粒径为8μm以下，多边形铁素体组的平均直径为15μm以下，由相邻的多边形的铁素体组的一组表示的多边形铁素体晶粒组 铁素体晶粒和残留奥氏体中的平均碳含量为0.70质量％以上，拉伸强度为780MPa以上。

公开(公告)号：US20140242416A1

公开(公告)日：2014-08-28

申请号：US14349234

申请日：2012-10-02

Applicant: JFE Steel Corporation

Inventor： Hiroshi Matsuda ,  Yoshimasa Funakawa ,  Kaneharu Okuda ,  Kazuhiro Seto

IPC: C23C2/02 ,  C22C38/38 ,  C22C38/32 ,  C22C38/28 ,  C22C38/16 ,  C22C38/00 ,  C22C38/12 ,  C22C38/08 ,  C22C38/06 ,  C22C38/04 ,  C22C38/02 ,  C21D8/02 ,  C22C38/14

CPC classification number: C21D8/0263 ,  C21D6/008 ,  C21D8/02 ,  C21D8/0226 ,  C21D8/0236 ,  C21D9/46 ,  C21D2211/001 ,  C21D2211/002 ,  C21D2211/005 ,  C21D2211/008 ,  C22C38/001 ,  C22C38/002 ,  C22C38/005 ,  C22C38/02 ,  C22C38/04 ,  C22C38/06 ,  C22C38/08 ,  C22C38/12 ,  C22C38/14 ,  C22C38/16 ,  C22C38/28 ,  C22C38/32 ,  C22C38/38 ,  C22C38/60 ,  C23C2/02 ,  C23C2/06 ,  C23C2/28 ,  C23C2/40 ,  Y10S148/909 ,  Y10T428/12799

Abstract: A high strength pressed member has excellent ductility and stretch flangeability and tensile strength of 780-1400 MPa, with a predetermined steel composition and steel microstructure relative to the entire microstructure of steel sheet, where area ratio of martensite 5-70%, area ratio of retained austenite 5-40%, area ratio of bainitic ferrite in upper bainite 5% or more, and total thereof is 40% or more, 25% or more of martensite is tempered martensite, polygonal ferrite area ratio is above 10% and below 50% to the entire microstructure of steel sheet, and average grain size is 8 μm or less, average diameter of a group of polygonal ferrite grains is 15 μm or less, the group of polygonal ferrite grains represented by a group of ferrite grains of adjacent polygonal ferrite grains, and average carbon content in retained austenite is 0.70 mass % or more and tensile strength is 780 MPa or more.

Abstract translation: 高强度压制构件具有优异的延展性和拉伸凸缘性和拉伸强度为780-1400MPa，具有预定的钢组成和钢组织相对于钢板的整个微观结构，其中马氏体的面积比为5-70％，面积比为 残留奥氏体5-40％，贝氏体铁素体在上贝氏体中的面积率为5％以上，总计为40％以上，25％以上的马氏体回火马氏体，多边形铁素体面积率在10％以下且低于50 ％的平均粒径为8μm以下，多边形铁素体组的平均直径为15μm以下，由相邻的多边形的铁素体组的一组表示的多边形铁素体晶粒组 铁素体晶粒和残留奥氏体中的平均碳含量为0.70质量％以上，拉伸强度为780MPa以上。