Title:
STEEL SHEET AND METHOD FOR MANUFACTURING SAME
Document Type and Number:
WIPO Patent Application WO/2020/225936
Kind Code:
A1
Abstract:
Provided is a steel sheet which has a predetermined chemical composition and structure, and in which the number density of (Fe,Mn)2B having an equivalent circle diameter of 50-300 cm is 1/500 µm2 or greater in a surface region extending from the surface of the steel sheet to a depth of 100 µm in the sheet thickness direction. Further provided is a method for manufacturing a steel sheet, including: a casting step for continuously casting molten steel having a predetermined chemical composition to form a steel billet, the casting step including introducing more than 10 ppm and less than 100 ppm of oxygen into the surface of the steel billet; a hot rolling step including finish-rolling the steel billet, the completion temperature in the finish rolling being 650-950°C in the hot rolling step; a step for winding the resultant hot-rolled steel sheet at a winding temperature of 400-700°C; and a step for cold-rolling and annealing the hot-rolled steel sheet.
Inventors:
TAKEDA KENGO (JP)
SUZUKI YUYA (JP)
NAKAMURA TOYOMITSU (JP)
FURUSAKO SEIJI (JP)
SUZUKI YUYA (JP)
NAKAMURA TOYOMITSU (JP)
FURUSAKO SEIJI (JP)
Application Number:
PCT/JP2019/044956
Publication Date:
November 12, 2020
Filing Date:
November 15, 2019
Export Citation:
Assignee:
NIPPON STEEL CORP (JP)
International Classes:
B22D11/00; C21D9/46; B22D11/11; C22C38/00; C22C38/60
Domestic Patent References:
| WO2018043456A1 | 2018-03-08 |
Foreign References:
| JP2019504196A | 2019-02-14 | |||
| JP2008231493A | 2008-10-02 | |||
| JP2004211158A | 2004-07-29 | |||
| JP6388099B1 | 2018-09-12 | |||
| JP2006249521A | 2006-09-21 |
Other References:
See also references of EP 3967779A4
Attorney, Agent or Firm:
AOKI, Atsushi et al. (JP)
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