Title:
HIGH STRENGTH HOT-DIP GALVANIZED STEEL SHEET AND MANUFACTURING METHOD THEREFOR
Document Type and Number:
WIPO Patent Application WO/2015/093043
Kind Code:
A1
Abstract:
Provided are a high strength hot-dip galvanized steel sheet and a high strength hot-dip galvannealed steel sheet, which are ideal as materials for automobile components and have a tensile strength (TS) of at least 1180 MPa and excellent spot-welding properties, impact resistance and bending workability, and a manufacturing method therefor. The amount of C is 0.15% or less; the ferrite area ratio is 10% or less, the bainitic ferrite area ratio is 2-30%, and the martensite area ratio is 60-98%; the residual austenite area ratio is less than 2%; the mean grain size of martensite that is adjacent to bainite is 15 µm or less; the proportion of massive martensite that is adjacent to bainite only in the total composition is 10% or less; and the value (∆Hv) obtained by subtracting the Vickers hardness at a position that is 20 µm from the surface of the steel sheet from the Vickers hardness at the 100 µm position is at least 30.
Inventors:
HASEGAWA HIROSHI (JP)
KANEKO SHINJIRO (JP)
MAKIMIZU YOICHI (JP)
SUZUKI YOSHITSUGU (JP)
KANEKO SHINJIRO (JP)
MAKIMIZU YOICHI (JP)
SUZUKI YOSHITSUGU (JP)
Application Number:
PCT/JP2014/006259
Publication Date:
June 25, 2015
Filing Date:
December 16, 2014
Export Citation:
Assignee:
JFE STEEL CORP (JP)
International Classes:
C22C38/00; C21D9/46; C22C38/38; C22C38/58; C23C2/06; C23C2/28; C23C2/40; C22C18/04
Foreign References:
| JP2013108154A | 2013-06-06 | |||
| JP2010070843A | 2010-04-02 | |||
| JP2010275628A | 2010-12-09 | |||
| JP2007009317A | 2007-01-18 | |||
| JP2010275600A | 2010-12-09 | |||
| JP2012031462A | 2012-02-16 | |||
| JP2011132602A | 2011-07-07 |
Other References:
TETSU-TO-HAGANE, vol. 83, no. 11, 1997, pages 748 - 753
See also references of EP 3054025A4
See also references of EP 3054025A4
Attorney, Agent or Firm:
KUMASAKA, Akira et al. (JP)
Akira Kumasaka (JP)
Akira Kumasaka (JP)
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