STEEL SHEET HOT-DIP-COATED WITH ZN-AL-MG-BASED SYSTEM HAVING EXCELLENT WORKABILITY AND METHOD FOR MANUFACTURING SAME

Title:

STEEL SHEET HOT-DIP-COATED WITH ZN-AL-MG-BASED SYSTEM HAVING EXCELLENT WORKABILITY AND METHOD FOR MANUFACTURING SAME

Document Type and Number:

WIPO Patent Application WO/2015/093596

Kind Code:

A1

Abstract:

The purpose of the present invention is to provide a steel sheet hot-dip coated with a Zn-Al-Mg-based system, which has such strength, ductility and hole-expandability as being suitable for working processes, for example, press working and stretch flanging, and high corrosion resistance. A high-strength steel sheet hot-dip coated with a Zn-Al-Mg-based system, which has excellent workability with a tensile strength of 400 MPa or greater, wherein: a steel sheet material thereof has a definite chemical composition; the Ti/C equivalence ratio represented by formula (1) is 0.4-1.5; a bainitic ferrite single phase or a phase comprising a bainitic ferrite phase and a ferrite phase exists as a main phase; the area ratio of a hard second phase and cementite is 3% or less; the ratio of a small angle boundary with a difference in crystal orientation of 2-15° is 30-75%; and a Ti-containing carbide having an average grain size of 20 nm or less is dispersed and deposited. Ti/C equivalence ratio = (Ti/48)/(C/12) (1)

Inventors:

HIRATA KENTAROU (JP)
UESUGI SHINYA (JP)
KATAGIRI YUKIO (JP)
URANAKA MASAAKI (JP)
SHIGETOMI TOMOHARU (JP)

Application Number:

PCT/JP2014/083712

Publication Date:

June 25, 2015

Filing Date:

December 19, 2014

Export Citation:

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Assignee:

NISSHIN STEEL CO LTD (JP)

International Classes:

C22C38/00; C21D9/46; C22C18/04; C22C38/14

Foreign References:

JP2007302992A	2007-11-22
JP2013133485A	2013-07-08
JP2011153361A	2011-08-11
JP2011144429A	2011-07-28
JP2013133497A	2013-07-08
JPH05179356A	1993-07-20
JP3591502B2	2004-11-24
JP2001303186A	2001-10-31
JP2001303187A	2001-10-31
JP2012193452A	2012-10-11

Other References: