Title:
HIGH-STRENGTH COLD-ROLLED STEEL SHEET HAVING EXCELLENT BENDING WORKABILITY AND MANUFACTURING METHOD THEREFOR
Document Type and Number:
WIPO Patent Application WO/2020/130675
Kind Code:
A1
Abstract:
A high-strength cold-rolled steel sheet having excellent bending workability according to an aspect of the present invention comprises, by weight %, 0.13-0.25 % of carbon (C), 1.0-2.0 % of silicon (Si), 1.5-3.0 % of manganese (Mn), 0.08-1.5 % of aluminum (Al)+chromium (Cr)+molybdenum (Mo), 0.1 % or less of phosphorus (P), 0.01 % or less of sulfur (S), 0.01 % or less of nitrogen (N), the remainder of Fe and inevitable impurities, and comprises, by area fraction, 3-25 % of ferrite, 20-40 % of martensite, and 5-20 % of residual austenite, in which a nickel-rich layer formed of nickel (Ni) introduced from outside is provided on a surface layer portion, and the concentration of nickel (Ni) at a depth of 1 ㎛ from the surface can be greater than or equal to 0.15 wt%.
Inventors:
CHO HANG-SIK (KR)
IM YOUNG-ROC (KR)
IM YOUNG-ROC (KR)
Application Number:
PCT/KR2019/018106
Publication Date:
June 25, 2020
Filing Date:
December 19, 2019
Export Citation:
Assignee:
POSCO (KR)
International Classes:
C22C38/38; C22C38/00; C22C38/02; C22C38/06; C22C38/22; C22C38/28; C22C38/32; C22C38/34; C23C2/06; C23C24/00
Foreign References:
| JP2014173138A | 2014-09-22 | |||
| KR101736632B1 | 2017-05-17 | |||
| KR101477877B1 | 2014-12-30 | |||
| KR101736635B1 | 2017-05-17 | |||
| JP2002047535A | 2002-02-15 | |||
| JP2014019905A | 2014-02-03 |
Other References:
See also references of EP 3901313A4
Attorney, Agent or Firm:
C&S PATENT AND LAW OFFICE (KR)
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