HIGH-STRENGTH HOT-ROLLED STEEL SHEET HAVING EXCELLENT YIELD RATIO, AND METHOD FOR MANUFACTURING SAME

Title:

HIGH-STRENGTH HOT-ROLLED STEEL SHEET HAVING EXCELLENT YIELD RATIO, AND METHOD FOR MANUFACTURING SAME

Document Type and Number:

WIPO Patent Application WO/2021/125563

Kind Code:

A1

Abstract:

Disclosed are a high-strength hot-rolled steel sheet having an excellent yield ratio and omitting post-processing, and a method for manufacturing the steel sheet. The hot-rolled steel sheet according to a disclosed embodiment comprises, in weight %, at least 0.12% and less than 0.3% of C, at most 0.5% (not including 0) of Si, 0.1 to 2.5% of Mn, 0.0005 to 0.005% of B, at most 0.02% of of P, at most 0.01% of S, and the remainder in iron (Fe) and unavoidable impurities, has a microstructure comprising at least 95 volume % of martensite, and has a yield ratio (yield strength/tensile strength) of at least 0.75, is manufactured by continuous hot-rolling, and allows post-processing with cold rolling and heat treatment to be omitted.

Inventors:

PARK KYONGSU (KR)
KIM DEUKJUNG (KR)
KIM HAK-JUN (KR)

Application Number:

PCT/KR2020/015769

Publication Date:

June 24, 2021

Filing Date:

November 11, 2020

Export Citation:

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Assignee:

POSCO (KR)

International Classes:

C21D8/02; B21B1/24; B21B3/00; C22C38/02; C22C38/04; C22C38/28

Foreign References:

JP2017057472A	2017-03-23
JP2018031077A	2018-03-01
JP2014201781A	2014-10-27
KR20120001018A	2012-01-04
KR20150046927A	2015-05-04
KR20050113247A	2005-12-01
JP2005298967A	2005-10-27
US20050155673A1	2005-07-21
EP1396549A1	2004-03-10

Other References: