公开(公告)号：US20170218472A1

公开(公告)日：2017-08-03

申请号：US15326116

申请日：2015-08-05

申请人： JFE STEEL CORPORATION

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

IPC分类号： 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分类号： 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

摘要： 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：US20210017636A1

公开(公告)日：2021-01-21

申请号：US16483500

申请日：2018-02-01

申请人： JFE STEEL CORPORATION

发明人： Taro KIZU ,  Noriaki MORIYASU ,  Shigeyuki NABESHIMA ,  Kazunori TAHARA ,  Kana SASAKI

IPC分类号： C23C2/06 ,  C22C38/12

摘要： There is provided a galvanized steel sheet more highly excellent in terms of punchability. The steel sheet has a specified chemical composition and a microstructure including a ferrite phase and a tempered bainite phase in a total amount of 95% or more in terms of area ratio, in which the average grain diameter of the microstructure is 5.0 μm or less, the amount of Fe precipitated is 0.10 mass % or more, the amount of Ti, Nb, and V precipitated in the form of precipitates having a grain diameter of less than 20 nm is 0.025 mass % or more in terms of precipitate C equivalent, and half or more of precipitates having a grain diameter of less than 20 nm are formed at random.

公开(公告)号：US20190226067A1

公开(公告)日：2019-07-25

申请号：US16326784

申请日：2017-08-29

申请人： JFE STEEL CORPORATION

发明人： Hidekazu MINAMI ,  Shinjiro KANEKO ,  Reiko SUGIHARA ,  Kazunori TAHARA ,  Kazuma MORI

IPC分类号： C22C38/60 ,  C22C38/16 ,  C22C38/14 ,  C22C38/12 ,  C22C38/00 ,  C22C38/02 ,  C22C38/04 ,  C22C38/06 ,  C22C38/34 ,  C22C38/36 ,  C23C2/06 ,  C23C2/40 ,  C21D8/02 ,  C21D9/46

摘要： A high-strength steel sheet having a TS of 780 MPa or more, excellent stretch flangeability, and excellent in-plane anisotropy of TS is provided. A high-strength steel sheet comprises: a predetermined chemical composition; a steel microstructure including, in area fraction, ferrite: 20% or more and 50% or less, lower bainite: 5% or more and 40% or less, martensite: 1% or more and 20% or less, and tempered martensite: 20% or less, and including, in volume fraction, retained austenite: 5% or more, the retained austenite having an average grain size of 2 μm or less; and a texture having an inverse intensity ratio of γ-fiber to α-fiber of 3.0 or less.

公开(公告)号：US20170211163A1

公开(公告)日：2017-07-27

申请号：US15326811

申请日：2015-08-05

申请人： JFE STEEL CORPORATION

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

IPC分类号： 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分类号： 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

摘要： 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.