Title:
HIGH-STRENGTH STEEL PLATE, HIGH-STRENGTH PLATED STEEL PLATE, METHOD FOR MANUFACTURING SAME, AND MEMBER
Document Type and Number:
WIPO Patent Application WO/2023/281939
Kind Code:
A1
Abstract:
The present invention provides a high-strength steel plate that has outstanding stretch flanging properties, bending properties, and LME resistance characteristics, and is such that components having high dimensional precision can be manufactured. A high-strength steel plate according to the present invention has a component composition which contains prescribed amounts of C, Si, Mn, P, S, Al, N, Nb, Ti, and B, is such that [％Si]/[％Mn] is between 0.10 and 0.60, inclusive, the amount of free Ti is 0.001 mass% or more, and the remainder is Fe and unavoidable impurities. The steel plate also has a steel structure where: the total of the amount of Nb solid solution and precipitation amount for 100 nm or less is 0.002 mass% or more; at a quarter-thickness position, the martensite surface ratio is 78% or more, the ferrite surface ratio is 10% or less, the residual austenite volume ratio is less than 10.0%, and the ratio of the grain diameter in the direction of rolling to the grain diameter in the plate-thickness direction of the prior austenite grains is 2.0 or less; the hardness fluctuation frequency per 1500 µm in the width direction at a 200-µm-thickness position is 10 times or less; and the tensile strength is 1180 MPa or more.
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Inventors:
MINAMI HIDEKAZU (JP)
WADA YUSUKE (JP)
TOJI YUKI (JP)
NISHIYAMA TAKESHI (JP)
SAEKI MICHITOSHI (JP)
WADA YUSUKE (JP)
TOJI YUKI (JP)
NISHIYAMA TAKESHI (JP)
SAEKI MICHITOSHI (JP)
Application Number:
PCT/JP2022/022198
Publication Date:
January 12, 2023
Filing Date:
May 31, 2022
Export Citation:
Assignee:
JFE STEEL CORP (JP)
International Classes:
C22C38/00; C21D9/46; C22C38/14; C22C38/60
Domestic Patent References:
| WO2021019947A1 | 2021-02-04 | |||
| WO2020129403A1 | 2020-06-25 | |||
| WO2018062380A1 | 2018-04-05 |
Foreign References:
| JP2021025094A | 2021-02-22 |
Attorney, Agent or Firm:
SUGIMURA Kenji (JP)
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