Title:
STEEL SHEET OF STRAIN AGING HARDENING TYPE WITH EXCELLENT AGING RESISTANCE AFTER PAINT BAKING AND PROCESS FOR PRODUCING SAME
Document Type and Number:
WIPO Patent Application WO/2012/070271
Kind Code:
A1
Abstract:
Provided is a steel sheet of the strain aging hardening type which combines ordinary-temperature non-aging properties with baking hardenability and has excellent aging resistance after paint baking. The steel sheet of the strain aging hardening type, which has excellent aging resistance after paint baking, contains, in terms of mass%, 0.0010-0.010% C, 0.005-1.0% Si, 0.08-1.0% Mn, 0.003-0.10% P, 0.0005-0.020% S, 0.010-0.10% Al, 0.005-0.20% Cr, 0.005-0.20% Mo, 0.002-0.10% Ti, 0.002-0.10% Nb, and 0.001-0.005% N, with the remainder comprising Fe and incidental impurities, and has a ferrite content of 98% or higher, the ferrite having an average grain diameter of 5-30 µm. In the steel sheet, the part located at a depth of 1/2 the sheet thickness and the surface-layer part each has a minimum dislocation density of 5×1012 or more and have an average dislocation density in the range of 5×1012-1×1015 per m2.
Inventors:
MARUYAMA NAOKI (JP)
HASHIMOTO KOJI (JP)
KAMEDA MASAHARU (JP)
HASHIMOTO KOJI (JP)
KAMEDA MASAHARU (JP)
Application Number:
PCT/JP2011/064317
Publication Date:
May 31, 2012
Filing Date:
June 22, 2011
Export Citation:
Assignee:
NIPPON STEEL CORP (JP)
MARUYAMA NAOKI (JP)
HASHIMOTO KOJI (JP)
KAMEDA MASAHARU (JP)
MARUYAMA NAOKI (JP)
HASHIMOTO KOJI (JP)
KAMEDA MASAHARU (JP)
International Classes:
C22C38/28; C21D9/46; C22C38/54
Foreign References:
| JP2002235117A | 2002-08-23 | |||
| JP2008110387A | 2008-05-15 | |||
| JP2009102673A | 2009-05-14 | |||
| JP2007077511A | 2007-03-29 |
Attorney, Agent or Firm:
HAGIWARA, Yasushi et al. (JP)
Yasushi Hagiwara (JP)
Yasushi Hagiwara (JP)
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Claims:
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