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/2019/003447
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 the average crystal grain size of prior austenite grains is 8 µm or less, the volume fraction of martensite is 90% or greater, there are an average of 10 or more cementites having a grain size of 0.05 µm or greater per 200 µm2 of steel sheet cross-sectional area, and there are an average of 10 or more Ti-based deposits having a grain size of less than 0.10 µm 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, 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 and high cross tensile strength after resistance spot welding are obtained therein at the same time.
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/JP2017/024257
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; C22C38/38; C22C38/60
Domestic Patent References:
| WO2015147216A1 | 2015-10-01 |
Foreign References:
| JP2007314817A | 2007-12-06 | |||
| JP2010174279A | 2010-08-12 | |||
| JP2010174278A | 2010-08-12 | |||
| JP2006152427A | 2006-06-15 | |||
| JP2017043825A | 2017-03-02 |
Attorney, Agent or Firm:
SUGIMURA Kenji (JP)
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