Title:
HOT-PRESSED MEMBER AND METHOD FOR MANUFACTURING SAME, AND COLD-ROLLED STEEL SHEET FOR HOT PRESSING
Document Type and Number:
WIPO Patent Application WO/2019/003451
Kind Code:
A1
Abstract:
In the hot-pressed member according to the present invention, after the component composition thereof is properly adjusted, the microstructure thereof is configured so that there are an average of 5 or more Ti-based deposits having a grain size of 0.1 µm or less per 100 µm2 of steel sheet cross-sectional area in a range from the steel sheet surface to a depth of 100 µm in the sheet thickness direction, the microstructure has a volume fraction of martensite of 95-100% in a depth range of 20-100 µm in the sheet thickness direction from the steel sheet surface, and there are an average of 10 or more cementites having a grain size of less than 0.2 µm among prior austenite grains, whereby the hot-pressed member not only has an extremely high tensile strength TS of 1780 MPa or greater after hot pressing, but excellent delayed fracture resistance after projection welding can also be obtained.
Inventors:
TAKASHIMA KATSUTOSHI (JP)
KOBAYASHI TAKASHI (JP)
FUNAKAWA YOSHIMASA (JP)
NAKAJIMA SEIJI (JP)
KOBAYASHI TAKASHI (JP)
FUNAKAWA YOSHIMASA (JP)
NAKAJIMA SEIJI (JP)
Application Number:
PCT/JP2017/024261
Publication Date:
January 03, 2019
Filing Date:
June 30, 2017
Export Citation:
Assignee:
JFE STEEL CORP (JP)
International Classes:
C22C38/00; B21D22/20; C21D1/18; C21D9/00; C21D9/46; C22C38/14; C22C38/60
Foreign References:
| JP2014015638A | 2014-01-30 | |||
| JP2013147749A | 2013-08-01 | |||
| JP2014040628A | 2014-03-06 | |||
| JP2010174282A | 2010-08-12 | |||
| JP2013122076A | 2013-06-20 | |||
| JP2003073774A | 2003-03-12 |
Attorney, Agent or Firm:
SUGIMURA Kenji (JP)
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