Title:
THIN STEEL SHEET, AND PRODUCTION METHOD THEREFOR
Document Type and Number:
WIPO Patent Application WO/2018/030503
Kind Code:
A1
Abstract:
Provided are: a thin steel sheet which has a tensile strength of 900 MPa or higher, and excellent weldability; and a production method therefor. The thin steel sheet is characterized by having a specific component composition, and a steel structure which includes, in terms of area ratio, at least 25% but not more than 65% of ferrite, at least 35% but not more than 75% of martensite having iron carbides precipitated in the grains thereof, and 20% or less (including 0%) in total of components other than the ferrite and the martensite as the remaining structure, said steel structure wherein the average grain sizes of the ferrite and the martensite are respectively 5 µm or lower, and the total Si and Mn on interfaces between the ferrite and the martensite is 5% or higher in terms of atomic concentration. The thin steel sheet is further characterized by having a tensile strength of 900 MPa or higher.
Inventors:
KOHSAKA NORIAKI (JP)
NAKAGAITO TATSUYA (JP)
YANG LINGLING (JP)
NAKAGAITO TATSUYA (JP)
YANG LINGLING (JP)
Application Number:
PCT/JP2017/029037
Publication Date:
February 15, 2018
Filing Date:
August 10, 2017
Export Citation:
Assignee:
JFE STEEL CORP (JP)
International Classes:
C22C38/00; C21D9/46; C22C18/00; C22C38/06; C22C38/60; C23C2/06; C23C2/28
Domestic Patent References:
| WO2012120020A1 | 2012-09-13 |
Foreign References:
| JP2014080665A | 2014-05-08 | |||
| JP2011132602A | 2011-07-07 | |||
| JP2010285636A | 2010-12-24 | |||
| JPS5858199B2 | 1983-12-23 | |||
| JP2015200013A | 2015-11-12 | |||
| JP2016037650A | 2016-03-22 |
Other References:
TAKAKO YAMASHITA ET AL.: "Analysis Technology of Microstructure Formation in Dual Phase Steel with High Performance", JFE GIHO NO. 37, February 2016 (2016-02-01), pages 22 - 25, XP055566264
See also references of EP 3476962A4
See also references of EP 3476962A4
Attorney, Agent or Firm:
KUMASAKA Akira et al. (JP)
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