STEEL SHEET, SURFACE-TREATED STEEL SHEET, AND METHOD FOR PRODUCING THE SAME

Title:

STEEL SHEET, SURFACE-TREATED STEEL SHEET, AND METHOD FOR PRODUCING THE SAME

Document Type and Number:

WIPO Patent Application WO/2010/058762

Kind Code:

A1

Abstract:

A high-strength steel sheet having excellent bending strength in the form of a tensile strength of 590 MPa or higher has a chemical composition of C: 0.03 to 0.20%, Si: 0.005 to 2.0%, Mn: 1.2 to 3.5%, P≤0.1% or less, S≤0.11% or less, sol. Al: 0.001 to 1.0%, N≤0.01%, and Bi: 0.0001 to 0.05%; arbitrarily contains Ti:≤0.3%, Nb:≤0.3%, V:≤0.3%, Cr:≤1%, Mo:≤1%, Cu:≤1%, Ni:≤1%, Ca:≤0.01%, Mg:≤0.01%, REM:≤0.01%, Zr:≤0.01%, and B:≤0.01%; and has an Mn segregation ratio (Mnmax/Mnav) of less than 1.30 as calculated from the average Mn concentration (Mnav) and the maximum Mn concentration (Mnmax) at a position of (1/20) the depth of sheet thickness from the steel sheet surface.

Inventors:

HAYASHI KOUTAROU (JP)
MIZUKAMI HIDEO (JP)

Application Number:

PCT/JP2009/069464

Publication Date:

May 27, 2010

Filing Date:

November 17, 2009

Export Citation:

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Assignee:

SUMITOMO METAL IND (JP)
HAYASHI KOUTAROU (JP)
MIZUKAMI HIDEO (JP)

International Classes:

C22C38/00; B21B3/00; B22D11/00; C21D9/46; C22C38/06; C22C38/58

Foreign References:

JP2008274379A	2008-11-13
JP2007197763A	2007-08-09
JP2007070649A	2007-03-22
JP2007070659A	2007-03-22
JPS6213533A	1987-01-22
JP2004211126A	2004-07-29
JP2004250774A	2004-09-09
JP2002161336A	2002-06-04
JP2002322539A	2002-11-08
JPH04191322A	1992-07-09
JP2007070649A	2007-03-22
JP2007070659A	2007-03-22

Other References: