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/2019/003450
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 grain size of prior austenite crystal grains within 50 µm from a steel sheet surface in the sheet thickness direction is 7 µm or less and the volume fraction of martensite is 90% or greater, and the average inter-particle distance between carbonitrides of Nb and Ti having a grain size of less than 0.10 µm in a depth range of 20-100 µm from the steel sheet surface in the sheet thickness direction is 5 µm or less, whereby the hot-pressed member can have not only an extremely high tensile strength TS of 1780 MPa or greater after hot pressing, but can be provided with excellent indentation peel strength of a projection-welded part at the same time.
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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/JP2017/024260
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:
| JP2010174282A | 2010-08-12 | |||
| JP2010174283A | 2010-08-12 | |||
| JP2007314817A | 2007-12-06 | |||
| JP2010065295A | 2010-03-25 |
Attorney, Agent or Firm:
SUGIMURA Kenji (JP)
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