Title:
HIGH-STRENGTH PLATED STEEL SHEET AND PRODUCTION METHOD FOR SAME
Document Type and Number:
WIPO Patent Application WO/2016/120914
Kind Code:
A1
Abstract:
Provided is a high-strength hot-dip-plated steel sheet that has a tensile strength of 780 MPa or higher and that has favorable workability. Also provided is a production method for the high-strength hot-dip-plated steel sheet. A high-strength hot-dip-plated steel sheet that has a steel sheet and a plating layer that is formed upon the steel sheet. The high-strength hot-dip-plated steel sheet is characterized by comprising a specific component composition and by having a steel structure that contains, by area ratio, 20% or less (including 0%) of a ferrite phase, 35%-90% of a bainite phase, and 10%-65% of a martensite phase and that contains, by number density per mm2, 400 or fewer inclusions that have an equivalent circle diameter of more than 5.0 μm, the granular martensite that constitutes the martensite phase having an average grain size of 4.0 μm or less, and the maximum length of the martensite being 5.0 μm or less. The high-strength hot-dip-plated steel sheet is also characterized in that, when the hardness at a position that is 1/4t (t being the thickness of the steel sheet) from the surface of the steel sheet in the thickness direction is taken to be 100%, the steel sheet has a surface hardness of 95%.
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Inventors:
KOHSAKA NORIAKI (JP)
FUNAKAWA YOSHIMASA (JP)
FUNAKAWA YOSHIMASA (JP)
Application Number:
PCT/JP2015/004173
Publication Date:
August 04, 2016
Filing Date:
August 20, 2015
Export Citation:
Assignee:
JFE STEEL CORP (JP)
International Classes:
C22C38/14; C21D8/02; C21D9/46; C22C38/58; C23C2/02; C23C2/06; C23C2/28; C23C2/40
Domestic Patent References:
| WO2011025042A1 | 2011-03-03 |
Foreign References:
| JP2012219342A | 2012-11-12 | |||
| JP2013147736A | 2013-08-01 | |||
| JP2013163827A | 2013-08-22 |
Attorney, Agent or Firm:
KUMASAKA, Akira et al. (JP)
Akira Kumasaka (JP)
Akira Kumasaka (JP)
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