Title:
HOT-PRESSED STEEL SHEET MEMBER AND METHOD FOR PRODUCING SAME
Document Type and Number:
WIPO Patent Application WO/2019/093376
Kind Code:
A1
Abstract:
Provided is a hot-pressed steel sheet member that has both a tensile strength of at least 1780 MPa and an excellent bending crushability. The hot-pressed steel sheet member contains, in mass%, at least 0.30% and less than 0.50% C, 0.01% to 2.0% Si, 0.5% to 3.5% Mn, 0.001% to 0.10% Nb, not more than 0.05% P, not more than 0.01% S, 0.01% to 1.00% Al, and not more than 0.01% N, with the balance being Fe and unavoidable impurities, and has a component composition in which the ratio C/Nb of the C content (mass%) to the Nb content (mass%) is 22 to 100. The hot-pressed steel sheet member has a microstructure in which the average crystal grain size of the prior austenite grains is not more than 8 μm, the martensite volume fraction is at least 90%, and the amount of solid-solution C is not more than 25% of the total amount of C and has a tensile strength of at least 1780 MPa.
Inventors:
TAKASHIMA KATSUTOSHI (JP)
FUTATSUKA TAKAYUKI (JP)
SATO KENTARO (JP)
YOSHIOKA SHIMPEI (JP)
ONO YOSHIHIKO (JP)
FUNAKAWA YOSHIMASA (JP)
FUTATSUKA TAKAYUKI (JP)
SATO KENTARO (JP)
YOSHIOKA SHIMPEI (JP)
ONO YOSHIHIKO (JP)
FUNAKAWA YOSHIMASA (JP)
Application Number:
PCT/JP2018/041343
Publication Date:
May 16, 2019
Filing Date:
November 07, 2018
Export Citation:
Assignee:
JFE STEEL CORP (JP)
International Classes:
C22C38/00; C21D1/18; C21D9/00; C21D9/46; C22C38/12; C22C38/58
Domestic Patent References:
| WO2017111456A1 | 2017-06-29 |
Foreign References:
| JP2014118613A | 2014-06-30 | |||
| JP2007211276A | 2007-08-23 | |||
| JP2016003389A | 2016-01-12 | |||
| JP2010174283A | 2010-08-12 | |||
| JP2014015638A | 2014-01-30 | |||
| JP2010150612A | 2010-07-08 | |||
| JP2013040390A | 2013-02-28 |
Other References:
See also references of EP 3680359A4
Attorney, Agent or Firm:
SUGIMURA Kenji (JP)
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