Title:
STEEL THIN PLATE HAVING HIGH STRENGTH AND METHOD FOR PRODUCTION THEREOF
Document Type and Number:
WIPO Patent Application WO/2001/020051
Kind Code:
A1
Abstract:
A steel thin plate which contains, in wt %, 0.04 to 0.1 % of C, 0.5 % or less of Si, 0.5 to 2 % of Mn, 0.05 % or less of P, 0.005 % or less of O and 0.005 % or less of S, and has an average ferrite grain diameter of 10 $g(m) m or less and a frequency of formation A, which is defined as the total length of a second phase structure in the form of a band observed per 1 mm?2¿ of the cross section of a plate along the direction of rolling, of 20 mm/mm?2¿ or less. The steel thin plate can be produced, for example, by a method comprising a step of subjecting a continuously cast slab containing the above-mentioned components, directly or after re-heating, to a hot rolling at its Ar3 transformation temperature or higher, and a step of cooling the hot rolled steel plate to a temperature of 600 to 750C within 2 seconds at a cooling rate of 100 - 2000 °C / s and winding it up at a temperature of 450 to 650C. The steel thin plate has a high strength of 340 Mpa or higher, and also is excellent in ductility, stretch-flanging property and impact resistance even after hot dip zinc plating and can be wound into a coil having good surface properties.
Inventors:
INOUE TADASHI (JP)
MOTOYASHIKI YOICHI (JP)
KIKUCHI HIROYASU (JP)
INAZUMI TORU (JP)
IMADA SADANORI (JP)
ODAKE TAKAYUKI (JP)
NAGATAKI YASUNOBU (JP)
MOTOYASHIKI YOICHI (JP)
KIKUCHI HIROYASU (JP)
INAZUMI TORU (JP)
IMADA SADANORI (JP)
ODAKE TAKAYUKI (JP)
NAGATAKI YASUNOBU (JP)
Application Number:
PCT/JP2000/006252
Publication Date:
March 22, 2001
Filing Date:
September 13, 2000
Export Citation:
Assignee:
NIPPON KOKAN KK (JP)
INOUE TADASHI (JP)
MOTOYASHIKI YOICHI (JP)
KIKUCHI HIROYASU (JP)
INAZUMI TORU (JP)
IMADA SADANORI (JP)
ODAKE TAKAYUKI (JP)
NAGATAKI YASUNOBU (JP)
INOUE TADASHI (JP)
MOTOYASHIKI YOICHI (JP)
KIKUCHI HIROYASU (JP)
INAZUMI TORU (JP)
IMADA SADANORI (JP)
ODAKE TAKAYUKI (JP)
NAGATAKI YASUNOBU (JP)
International Classes:
C21D8/02; C22C38/00; C22C38/04; C22C38/12; C22C38/14; C22C38/24; C23C2/02; (IPC1-7): C22C38/00; C21D9/46
Foreign References:
| JPH0317244A | 1991-01-25 | |||
| JPH0756053B2 | 1995-06-14 | |||
| JPH0754051A | 1995-02-28 | |||
| JP2555436B2 | 1996-11-20 |
Other References:
See also references of EP 1143022A4
Attorney, Agent or Firm:
Takano, Shigeru (Minamiwatarida-cho Kawasaki-ku, Kaswasaki-shi Kanagawa, JP)
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