Title:
STEEL FOR MECHANICAL STRUCTURE FOR COLD WORKING, AND METHOD FOR MANUFACTURING SAME
Document Type and Number:
WIPO Patent Application WO/2013/094475
Kind Code:
A1
Abstract:
Provided are a steel for a mechanical structure for cold working, and a method for manufacturing the same, whereby softening and variations in hardness can be reduced even when a conventional spheroidizing annealing process is performed. A steel having a predetermined chemical composition, the total area ratio of pearlite and pro-eutectoid ferrite being at least 90 area% with respect to the total metallographic structure of the steel, the area ratio (A) of pro-eutectoid ferrite satisfying the relationship A > Ae with an Ae value expressed by a predetermined relational expression, the average equivalent circular diameter of bcc-Fe crystal grains being 15-35 µm, and the average of the maximum grain diameter and the second largest grain diameter of the bcc-Fe crystal grains being 50 µm or less in terms of equivalent circular diameter.
Inventors:
YAMASHITA KOUJI (JP)
TSUCHIDA TAKEHIRO (JP)
CHIBA MASAMICHI (JP)
TSUCHIDA TAKEHIRO (JP)
CHIBA MASAMICHI (JP)
Application Number:
PCT/JP2012/082063
Publication Date:
June 27, 2013
Filing Date:
December 11, 2012
Export Citation:
Assignee:
KOBE STEEL LTD (JP)
International Classes:
C22C38/06; C21D8/06; C22C38/54
Foreign References:
| JP2009275252A | 2009-11-26 | |||
| JP2010236005A | 2010-10-21 | |||
| JP2010159476A | 2010-07-22 | |||
| JPH1112684A | 1999-01-19 | |||
| JP2013007088A | 2013-01-10 | |||
| JP2013007090A | 2013-01-10 | |||
| JP2000119809A | 2000-04-25 | |||
| JP2009275252A | 2009-11-26 | |||
| JP2000073137A | 2000-03-07 |
Other References:
See also references of EP 2796586A4
Attorney, Agent or Firm:
HAMADA Yuriko et al. (JP)
Yuriko Hamada (JP)
Yuriko Hamada (JP)
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Claims: