Title:
ULTRA-HIGH STRENGTH COLD-ROLLED STEEL SHEET AND MANUFACTURING METHOD THEREFOR
Document Type and Number:
WIPO Patent Application WO/2023/234503
Kind Code:
A1
Abstract:
An ultra-high strength cold-rolled steel sheet of the present invention comprises, in weight%, 0.23% to 0.40% of carbon (C), 0.05% to 1.0% of silicon (Si), 0.5% to 3.0% of manganese (Mn), 0.01% to 0.12% of vanadium (V), 0.01% to 0.3% of aluminum (Al), 0% (exclusive) to 0.5% (inclusive) of chromium (Cr), 0% (exclusive) to 0.1% (inclusive) of titanium (Ti), 0% (exclusive) to 0.02% (inclusive) of phosphorus (P), 0% (exclusive) to 0.01% (inclusive) of sulfur (S), 0.001% to 0.005% of boron (B), and the balance being iron (Fe) and other inevitable impurities, wherein the final microstructure of the steel sheet comprises tempered martensite with a volume fraction of 90% or more; the average separation distance between precipitates in the tempered martensite is 300 nm or longer; the average size of the precipitates is 200 nm or smaller; and the number of precipitates with an average size of 40 nm or smaller on the basis of an area of 20 ㎛2 in the final microstructure is 25 or more.
Inventors:
MAENG HAN SOL (KR)
LEE SANG WOOK (KR)
PARK BONG JUNE (KR)
HAN SEONG KYUNG (KR)
LEE SANG WOOK (KR)
PARK BONG JUNE (KR)
HAN SEONG KYUNG (KR)
Application Number:
PCT/KR2022/019639
Publication Date:
December 07, 2023
Filing Date:
December 05, 2022
Export Citation:
Assignee:
HYUNDAI STEEL CO (KR)
International Classes:
C22C38/38; C21D8/02; C21D9/46; C22C38/24; C22C38/28; C22C38/32
Domestic Patent References:
| WO2014019964A1 | 2014-02-06 |
Foreign References:
| KR20200118445A | 2020-10-15 | |||
| KR20090122346A | 2009-11-27 | |||
| KR102403767B1 | 2022-05-30 | |||
| JP2010037652A | 2010-02-18 |
Attorney, Agent or Firm:
LEE, In Haeng et al. (KR)
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