Title:
HIGH STRENGTH STEEL SHEET AND MANUFACTURING METHOD THEREFOR
Document Type and Number:
WIPO Patent Application WO/2016/143298
Kind Code:
A1
Abstract:
The purpose of the present invention is to provide: a high strength steel sheet that has high strength such that tensile strength is at least 780 MPa, and excellent blanking quality combined with stretch-flangeability; and a manufacturing method therefor. Provided is a high strength steel sheet wherein: the steel sheet contains, in mass%, C: 0.05-0.30%, Si: 0.6-2.0%, Mn 1.3-3.0%, P: not more than 0.10%, S: not more than 0.030%, Al: not more than 2.0%, N: not more than 0.010%, and one or more of Ti, Nb and V: 0.01-1.0% each, the balance being obtained from iron and unavoidable impurities; the steel sheet comprises at least 50% area ratio of ferrite structure; the amount of Fe deposited is at least 0.04 mass%; the steel sheet contains a deposit in which the particle diameter is less than 20 nm; and C* defined by expression (1) and C*p defined by expression (2) satisfy the conditions in expressions (3)-(5). C*=([Ti]/48+[Nb]/93+[V]/51+[Mo]/96+[Ta]/181+[W]/184) × 12... (1) C*p=([Ti]p/48+[Nb]p/93+[V]p/51+[Mo]p/96+[Ta]p/181+[W]p/184) × 12... (2) C* ≥ 0.035... (3) −0.015 ≤ [C]−C* ≤ 0.03... (4) C*p/C* ≥ 0.3... (5)
Inventors:
KIZU TARO (JP)
TOYODA SHUNSUKE (JP)
KIDO AKIMASA (JP)
TADANI TETSUSHI (JP)
TOYODA SHUNSUKE (JP)
KIDO AKIMASA (JP)
TADANI TETSUSHI (JP)
Application Number:
PCT/JP2016/001107
Publication Date:
September 15, 2016
Filing Date:
March 01, 2016
Export Citation:
Assignee:
JFE STEEL CORP (JP)
International Classes:
C22C38/00; C21D9/46; C22C38/14; C22C38/60
Foreign References:
| JP2009167475A | 2009-07-30 | |||
| JP2009191360A | 2009-08-27 | |||
| JP2009280899A | 2009-12-03 | |||
| JP2011017060A | 2011-01-27 |
Other References:
See also references of EP 3266897A4
Attorney, Agent or Firm:
SUGIMURA, KENJI (JP)
Kenji Sugimura (JP)
Kenji Sugimura (JP)
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