Title:
HIGH-STRENGTH STEEL HAVING EXCELLENT LOW-YIELD-RATIO CHARACTERISTICS, AND MANUFACTURING METHOD THEREFOR
Document Type and Number:
WIPO Patent Application WO/2019/125091
Kind Code:
A1
Abstract:
A high-strength steel having excellent low-yield-ratio characteristics, according to one embodiment of the present invention, comprises, by wt%, 0.06-0.12% of C, 0.2-0.5% of Si, 1.5-2.0% of Mn, 0.003-0.05% of Al, 0.01% or less of N, 0.02% or less of P, 0.003% or less of S, 0.05-0.5% of Cr, 0.05-0.5% of Mo, 0.01-0.05% of Nb, 0.0005-0.005% of Ca and the balance of Fe and other inevitable impurities, and comprises polygonal ferrite as a microstructure, wherein the area fraction of the polygonal ferrite is 10-30% and the average hardness of the polygonal ferrite can be 180 Hv or less.
Inventors:
JUNG HWAN-GYO (KR)
Application Number:
PCT/KR2018/016593
Publication Date:
June 27, 2019
Filing Date:
December 24, 2018
Export Citation:
Assignee:
POSCO (KR)
International Classes:
C22C38/38; C21D6/00; C21D8/00; C22C38/00; C22C38/20; C22C38/22; C22C38/26; C22C38/28; C22C38/32; C22C38/58
Foreign References:
| KR20130073472A | 2013-07-03 | |||
| KR20150038727A | 2015-04-08 | |||
| JP2013023714A | 2013-02-04 | |||
| KR20140055460A | 2014-05-09 | |||
| JP2006336065A | 2006-12-14 | |||
| KR970043168A | 1997-07-26 |
Other References:
See also references of EP 3730653A4
Attorney, Agent or Firm:
C&S PATENT AND LAW OFFICE (KR)
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