Title:
HIGH-STRENGTH STEEL SHEET
Document Type and Number:
WIPO Patent Application WO/2018/020660
Kind Code:
A1
Abstract:
Provided is a high-strength steel sheet which has a prescribed chemical composition and comprises one or two types of martensite and bainite in which the DI is 2.0 to 7.8, the Pcm is 0.189% or more, and the metallic structure is 99% or more in total area ratio. The aspect ratio of old austenite grains is 2.0 or more; the number fraction of cementite in which the length in the long axis direction is 1.0 μm or more relative to cementite in which the length in the long axis direction is 0.1 μm or more is 5% or less; the sheet thickness is 4.5 to 20 mm; the yield strength is 885 MPa or more; the tensile strength is 950 MPa or more; the breaking elongation is 12% or more; and the Charpy absorbed energy at -20°C is 59 J/cm2 or more.
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Inventors:
YOSHIMURA MASAHIDE (JP)
MINAGAWA MASANORI (JP)
KAWABATA NORIMASA (JP)
TSUZUKI TAKESHI (JP)
MINAGAWA MASANORI (JP)
KAWABATA NORIMASA (JP)
TSUZUKI TAKESHI (JP)
Application Number:
PCT/JP2016/072316
Publication Date:
February 01, 2018
Filing Date:
July 29, 2016
Export Citation:
Assignee:
NIPPON STEEL & SUMITOMO METAL CORP (JP)
International Classes:
C22C38/00; C21D8/02; C22C38/14; C22C38/58
Domestic Patent References:
| WO2012060405A1 | 2012-05-10 | |||
| WO2011142285A1 | 2011-11-17 | |||
| WO2014154104A1 | 2014-10-02 |
Foreign References:
| JP2014529686A | 2014-11-13 | |||
| JP2011052321A | 2011-03-17 | |||
| JP2014047414A | 2014-03-17 | |||
| JP2008184638A | 2008-08-14 | |||
| JP2010070845A | 2010-04-02 |
Other References:
See also references of EP 3492610A4
Attorney, Agent or Firm:
SHIGA Masatake et al. (JP)
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