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Title:
METHOD FOR PRODUCING STEEL MATERIAL
Document Type and Number:
Japanese Patent JP2013189692
Kind Code:
A
Abstract:

To provide a method for producing a steel material which produces a steel material having high strength and high ductility.

Parent materials 1a and 1b for a steel material are heated to at least AC1 point, which is the temperature at which austenite appears, causing austenite to appear in the parent materials 1a and 1b (S101). An amount of strain predicted to cause Mf point to drop below room temperature is applied to the parent materials (S102), the Mf point being the temperature at which the composition of the parent materials 1a and 1b as a whole changes to martensite. This prevents the composition of the steel material as a whole from changing to martensite when the steel material is cooled to room temperature. The parent materials 1a and 1b are cooled to room temperature at a cooling speed at which, in a CCT diagram, a line extrapolated from the cooling curve of the parent materials 1a and 1b intersects with the region in which martensite is produced (S103). At room temperature, austenite remains in the composition of the steel material produced. Thus, the steel material which has high ductility while having high strength can be produced.


Inventors:
FUJII HIDETOSHI
MORISADA YOSHIAKI
Application Number:
JP2012057986A
Publication Date:
September 26, 2013
Filing Date:
March 14, 2012
Export Citation:
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Assignee:
UNIV OSAKA
International Classes:
C21D6/00; C21D7/00; B23K20/12; C22C38/00; C22C38/26; C22C38/44
Domestic Patent References:
JP2008073694A2008-04-03
JP2012040584A2012-03-01
Foreign References:
WO2010059201A22010-05-27
Attorney, Agent or Firm:
Yoshiki Hasegawa
Yoshiki Kuroki
Ohno Arata



 
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