ULTRAHIGH STRENGTH COLD-ROLLED STEEL SHEET AND MANUFACTURING METHOD THEREOF

Title:

ULTRAHIGH STRENGTH COLD-ROLLED STEEL SHEET AND MANUFACTURING METHOD THEREOF

Document Type and Number:

WIPO Patent Application WO/2019/125018

Kind Code:

A1

Abstract:

An ultrahigh strength cold-rolled steel sheet and a manufacturing method thereof are provided. An ultrahigh strength cold-rolled steel sheet, according to a preferred aspect of the present invention, comprises, in percentage by weight: C: 0.25 to 0.4%; Si: 0.5% or less (excluding 0); Mn: 3.0 to 4.0%; P: 0.03% or less (excluding 0); S: 0.015% or less (excluding 0); Al: 0.1% or less; Ti: 48/14*[N] to 0.1% or less; Nb: 0.1% or less (excluding 0); B: 0.005% or less (excluding 0); N: 0.01% (excluding 0); and the balance consisting of Fe and impurities, and a microstructure thereof includes 90% and more (including 100%) of martensite, and one or two kinds of 10% or less (including 0%) of ferrite and bainite.

Inventors:

KOO MIN-SEO (KR)
SUH IN-SHIK (KR)

Application Number:

PCT/KR2018/016371

Publication Date:

June 27, 2019

Filing Date:

December 20, 2018

Export Citation:

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Assignee:

POSCO (KR)

International Classes:

C22C38/04; C21D8/02; C21D9/46; C22C38/26; C22C38/28; C22C38/32

Foreign References:

KR20120074798A	2012-07-06
KR20140055463A	2014-05-09
JP2014196557A	2014-10-16
JP2010065272A	2010-03-25
KR20120063198A	2012-06-15
KR20120063198A	2012-06-15
JP2010090432A	2010-04-22
KR20177001783A

Other References: