Title:
伸びフランジ性に優れた高強度熱延鋼板およびその製造方法
Document Type and Number:
Japanese Patent JP5765080
Kind Code:
B2
Abstract:
Provided are a high strength hot-rolled steel sheet combining strength with stretch-flange formability and a method for manufacturing the same. The high strength hot-rolled steel sheet has a composition containing more than 0.035% to 0.055% C, 0.2% or less Si, 0.35% or less Mn, 0.03% or less P, 0.03% or less S, 0.1% or less Al, 0.01% or less N, 0.08% to 0.25% Ti, and 0.0005% to 0.0035% B on a mass basis, solute B being 0.0005% or more, the remainder being Fe and unavoidable impurities; a matrix containing a ferrite phase having an area fraction of more than 95%; a microstructure in which Ti carbides having an average grain size of less than 10 nm are finely precipitated in grains of the ferrite phase and the volume fraction of the Ti carbides is 0.0015 to 0.007; a tensile strength of 780 MPa or more; and excellent stretch-flange formability.
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Inventors:
Yoshimasa Funagawa
Ariga Tamako
Eiaki Moriyasu
Takayuki Murata
Ariga Tamako
Eiaki Moriyasu
Takayuki Murata
Application Number:
JP2011137680A
Publication Date:
August 19, 2015
Filing Date:
June 21, 2011
Export Citation:
Assignee:
jfe Steel Corporation
International Classes:
C22C38/00; C21D9/46; C22C38/14; C22C38/54; C23C2/06
Domestic Patent References:
| JP2005154809A | ||||
| JP2002322539A | ||||
| JP2009052139A |
Attorney, Agent or Firm:
Kenichiro Ochiai
Eiichi Kobayashi
Eiichi Kobayashi