HIGH-STRENGTH STEEL HAVING HIGH YIELD RATIO AND EXCELLENT DURABILITY, AND METHOD FOR PRODUCING SAME

Title:

HIGH-STRENGTH STEEL HAVING HIGH YIELD RATIO AND EXCELLENT DURABILITY, AND METHOD FOR PRODUCING SAME

Document Type and Number:

WIPO Patent Application WO/2021/091140

Kind Code:

A1

Abstract:

Thick high-strength steel having a high yield ratio and excellent durability, and a method for manufacturing same are provided. The thick high-strength steel having a high yield ratio and excellent durability of the present invention comprises, in percentage by weight: C: 0.05-0.15%; Si: 0.01-1.0%; Mn: 1.0-2.3%; Al: 0.01-0.1%; Cr: 0.005-1.0%; P: 0.001-0.05%; S: 0.001-0.01%; N: 0.001-0.01%; Nb: 0.005-0.07%; Ti: 0.005-0.11%; and Fe and unavoidable impurities, and has a microstructure comprising, in percentage by area: less than 5% of a pearlite phase; less than 10% of a bainite phase; and less than 5% of a martensite and austenite (MA) phase; and the remaining of a ferrite phase, and including nitrides and coarse carbides having a diameter of 1 μm or more, wherein the ratio of fatigue limit and yield strength is 0.15 or more and the yield ratio is 0.8 or more.

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Inventors:

KIM SUNG-IL (KR)
NA HYUN-TAEK (KR)

Application Number:

PCT/KR2020/014670

Publication Date:

May 14, 2021

Filing Date:

October 26, 2020

Export Citation:

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Assignee:

POSCO (KR)

International Classes:

C22C38/04; C21D8/02; C22C38/02

Foreign References:

KR20150074943A	2015-07-02
JP2015175004A	2015-10-05
JP2018090896A	2018-06-14
JPH11310852A	1999-11-09
KR20060033489A	2006-04-19
JPH05308808A	1993-11-22
JPH05279379A	1993-10-26
KR101528084B1	2015-06-10
JPH09143570A	1997-06-03

Other References: