Title:
HIGH-YIELD-RATIO HIGH-STRENGTH COLD-ROLLED STEEL SHEET AND METHOD FOR PRODUCING SAME
Document Type and Number:
WIPO Patent Application WO/2013/088666
Kind Code:
A1
Abstract:
A steel sheet having the following chemical composition, in mass%: 0.06-0.13% of C, 1.2-2.3% of Si, 0.6-1.6% of Mn, 0.10% or less of P, 0.010% or less of S, 0.01-0.10% of Al, and 0.010% or less of N, the remainder comprising Fe and inevitable impurities. The microstructure of the steel sheet includes, in volume fraction, 90% or more of ferrite having a mean grain size of less than 20 μm, and 1.0-10% of perlite having a mean grain size less than 5 μm. A high-yield-ratio high-strength cold-rolled steel sheet of excellent elongation and stretch-flangeability where the ferrite has a mean Vickers hardness of 130 or higher, the yield ratio is 65% or higher, and the tensile strength is 590 MPa or greater.
Inventors:
TAKASHIMA KATSUTOSHI (JP)
TOJI YUKI (JP)
HASEGAWA KOHEI (JP)
TOJI YUKI (JP)
HASEGAWA KOHEI (JP)
Application Number:
PCT/JP2012/007720
Publication Date:
June 20, 2013
Filing Date:
December 03, 2012
Export Citation:
Assignee:
JFE STEEL CORP (JP)
International Classes:
C22C38/00; B21B3/00; C21D9/46; C22C38/06; C22C38/58
Foreign References:
| JP2011168878A | 2011-09-01 | |||
| JP2011168879A | 2011-09-01 | |||
| JP2011168876A | 2011-09-01 | |||
| JP2011168880A | 2011-09-01 | |||
| JP2010255097A | 2010-11-11 | |||
| JP2007211280A | 2007-08-23 | |||
| JP2011153368A | 2011-08-11 | |||
| JP2688384B2 | 1997-12-10 | |||
| JP2008174776A | 2008-07-31 | |||
| JP2009235441A | 2009-10-15 | |||
| JP3887235B2 | 2007-02-28 | |||
| JP2009185355A | 2009-08-20 | |||
| JP4662175B2 | 2011-03-30 | |||
| JP4696870B2 | 2011-06-08 |
Other References:
See also references of EP 2792762A4
Attorney, Agent or Firm:
KUMASAKA, Akira et al. (JP)
Akira Kumasaka (JP)
Akira Kumasaka (JP)
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Claims: