Title:
HIGH-STRENGTH HOT-ROLLED STEEL SHEET AND MANUFACTURING METHOD THEREFOR
Document Type and Number:
WIPO Patent Application WO/2013/099183
Kind Code:
A1
Abstract:
Provided are: a high-strength hot-rolled steel sheet that combines excellent strength and workability; and a manufacturing method therefor. By mass, said steel sheet contains more than 0.035% and no more than 0.065% carbon, up to 0.2% silicon, up to 0.65% manganese, up to 0.03% phosphorus, up to 0.02% sulfur, up to 0.1% aluminum, up to 0.01% nitrogen, and 0.09-0.25% titanium, with the remainder comprising iron and unavoidable impurities. By area fraction, a ferrite phase constitutes more than 95% of the metal structure, titanium carbide with a mean grain diameter of 5 nm or less is finely dispersed inside the crystal grains of the ferrite phase, and the mean diameter of said ferrite crystal grains is at least 1 µm. This results in a high-strength hot-rolled steel sheet with a tensile strength of at least 780 MPa.
Inventors:
FUNAKAWA YOSHIMASA (JP)
ARIGA TAMAKO (JP)
MORIYASU NORIAKI (JP)
MURATA TAKAYUKI (JP)
OWADA HIROSHI (JP)
ARIGA TAMAKO (JP)
MORIYASU NORIAKI (JP)
MURATA TAKAYUKI (JP)
OWADA HIROSHI (JP)
Application Number:
PCT/JP2012/008190
Publication Date:
July 04, 2013
Filing Date:
December 21, 2012
Export Citation:
Assignee:
JFE STEEL CORP (JP)
International Classes:
C22C38/00; C21D9/46; C22C18/04; C22C38/14; C22C38/60; C23C2/06; C23C2/40
Domestic Patent References:
| WO2011162412A1 | 2011-12-29 |
Foreign References:
| JP2004137607A | 2004-05-13 | |||
| JP2005154809A | 2005-06-16 | |||
| JP2003321735A | 2003-11-14 | |||
| JP2000273577A | 2000-10-03 | |||
| JP2000212690A | 2000-08-02 | |||
| JPS56169727A | 1981-12-26 |
Other References:
MASAHIKO MORITA ET AL.: "Development of Hot rolled High Strength Steels Hardened by Precipitation hardening with High Stretch Flanging", CURRENT ADVANCES IN MATERIALS AND PROCESSES, vol. 5, no. 6, September 1992 (1992-09-01), pages 1863 - 1866
Attorney, Agent or Firm:
KUMASAKA, Akira et al. (JP)
Akira Kumasaka (JP)
Akira Kumasaka (JP)
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Claims: