Title:
STEEL MEMBER AND PROCESS FOR PRODUCING SAME
Document Type and Number:
WIPO Patent Application WO/2014/073415
Kind Code:
A1
Abstract:
Provided is a steel member which is obtained using a thick steel plate and in which the inner zone (thicknesswise central zone) of the steel material exhibits high strength and high toughness even in a case where the steel member has undergone high -temperature and long-time post-welding heat treatment. The steel member has a prescribed composition and is characterized in that the texture of a thicknesswise central zone of the plate satisfies all the requirements (a) to (d): (a) the texture is tempered bainite and/or tempered martensite; (b) the mean equivalent circle diameter of grains that are each surrounded by a large-angle grain boundary where the misorientation between two adjacent grains is 15º or more is 20μm or less; (c) the maximum diameter of grain-boundary carbides is 0.8μm or less; and (d) the fraction of grain-boundary carbides is 1.0% by area or more.
Inventors:
YAMAGUCHI TETSUO
Application Number:
PCT/JP2013/079197
Publication Date:
May 15, 2014
Filing Date:
October 29, 2013
Export Citation:
Assignee:
KOBE STEEL LTD (JP)
International Classes:
C22C38/00; C21D6/00; C21D9/50; C22C38/54
Foreign References:
| JP2006045672A | 2006-02-16 | |||
| JP2008291363A | 2008-12-04 | |||
| JP2000178645A | 2000-06-27 | |||
| JP2012036501A | 2012-02-23 | |||
| JP2743765B2 | 1998-04-22 | |||
| JP2000345281A | 2000-12-12 |
Other References:
See also references of EP 2918694A4
Attorney, Agent or Firm:
UEKI, Kyuichi et al. (JP)
Hisakazu Ueki (JP)
Hisakazu Ueki (JP)
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