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Patent Searching and Data


Title:
HIGH-STRENGTH STEEL SHEET, AND PRODUCTION METHOD THEREFOR
Document Type and Number:
WIPO Patent Application WO/2018/030502
Kind Code:
A1
Abstract:
Provided is a high-strength steel sheet which has a tensile strength of 980 MPa or higher, and excellent mouldability. This high-strength steel sheet has a specific component composition, and a structure in which the average grain size of a ferrite phase is 1.5 µm or lower, the area ratio of the ferrite phase is at least 2% but not more than 15%, the area ratio of a tempered martensite phase is at least 75% but not more than 96%, and the total value of the lengths of interfaces between an untempered martensite phase and the ferrite phase, and the lengths of interfaces between the untempered martensite phase and the tempered martensite phase, per unit area, is at least 6.3×108 µm/m2 but not more than 5.0×1011 µm/m2.

Inventors:
KOHSAKA NORIAKI (JP)
SAKURAI MICHITAKA (JP)
SUZUKI YOSHIKAZU (JP)
HIMEI YOSHIMASA (JP)
Application Number:
PCT/JP2017/029036
Publication Date:
February 15, 2018
Filing Date:
August 10, 2017
Export Citation:
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Assignee:
JFE STEEL CORP (JP)
International Classes:
C22C38/00; C21D9/46; C22C18/00; C22C38/38; C22C38/58; C23C2/06; C23C2/28
Domestic Patent References:
WO2016067623A12016-05-06
Foreign References:
JP2011111670A2011-06-09
JP2013014822A2013-01-24
JP2014173151A2014-09-22
KR20130110634A2013-10-10
JP2005256044A2005-09-22
JP2011052295A2011-03-17
JP2012031462A2012-02-16
JP2015117403A2015-06-25
Other References:
See also references of EP 3498876A4
Attorney, Agent or Firm:
KUMASAKA Akira et al. (JP)
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