HOT-ROLLED STEEL SHEET AND METHOD FOR MANUFACTURING SAME

Title:

HOT-ROLLED STEEL SHEET AND METHOD FOR MANUFACTURING SAME

Document Type and Number:

WIPO Patent Application WO/2014/188966

Kind Code:

A1

Abstract:

　The hot-rolled steel sheet according to the present invention has a composition containing, in terms of percent by mass, 0.01-0.2% of C, 2.5% or less of Si, 4.0% or less of Mn, 0.10% or less of P, 0.03% or less of S, 0.001-2.0% of Al, 0.01% or less of N, and 0.01% or less of O, and containing a total of 0.01-0.30% of one or both of Ti and Nb, the mean effective crystal grain size in a portion 1/4 of the sheet thickness is 10 μm or less, the mean effective crystal grain size in a portion at a range of 50 μm from a surface is 6 μm or less, and the structure of the steel sheet is annealed martensite or lower bainite, the total volume fraction thereof being at least 90%.

Inventors:

SHUTO HIROSHI (JP)
AZUMA MASAFUMI (JP)
SAKAKIBARA AKIFUMI (JP)
KANZAWA YUUKI (JP)
KIMURA KEN (JP)

Application Number:

PCT/JP2014/063026

Publication Date:

November 27, 2014

Filing Date:

May 16, 2014

Export Citation:

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Assignee:

NIPPON STEEL & SUMITOMO METAL CORP (JP)

International Classes:

C22C38/00; B21B1/26; B21B3/00; C21D9/46; C22C38/14; C22C38/58; C23C2/06; C23C2/40

Domestic Patent References:

WO2012133636A1	2012-10-04
WO2010074473A2	2010-07-01

Foreign References:

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Other References: