HOT-ROLLED STEEL SHEET - NIPPON STEEL & SUMITOMO METAL CORP

Title:

HOT-ROLLED STEEL SHEET

Document Type and Number:

WIPO Patent Application WO/2018/179388

Kind Code:

A1

Abstract:

A hot-rolled steel sheet, wherein: the chemical composition, in mass%, is C: 0.020-0.180%, Si: 0.05-1.70%, Mn: 0.50-2.50%, Al: 0.010-1.000%, N: 0.0060%, P≤0.050%, S≤0.005%, Ti: 0-0.150%, Nb: 0-0.100%, V: 0-0.300%, Cu: 0-2.00%, Ni: 0-2.00%, Cr: 0-2.00%, Mo: 0-1.00%, B: 0-0.0100%, Mg: 0-0.0100%, Ca: 0-0.0100%, REM: 0-0.1000%, Zr: 0-1.000%, Co: 0-1.000%, Zn: 0-1.000%, W: 0-1.000%, balance: Fe and impurities; the metal structure in the locations that are 1/4W or 3/4W from the end faces of the steel sheet and 1/4t or 3/4t from the surface is, in area%, martensite: greater than 2% to 10%, retained austenite < 2%, bainite ≤ 40%, pearlite ≤ 2%, balance: ferrite; the mean equivalent circular diameter of the metal phases made of martensite/retained austenite is 1.0-5.0 µm; the mean value for the shortest distance between adjacent metal phases is at least 3µm; and the standard deviation of nanohardness is 2.0 GPa or less.

Inventors:

YOKOI TATSUO (JP)
YOSHIKAWA NOBUO (JP)
YONEMURA SHIGERU (JP)
OOTSUKA KAZUYA (JP)

Application Number:

PCT/JP2017/013746

Publication Date:

October 04, 2018

Filing Date:

March 31, 2017

Export Citation:

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Assignee:

NIPPON STEEL & SUMITOMO METAL CORP (JP)

International Classes:

C22C38/00; C22C38/58; C21D9/46

Domestic Patent References:

WO2015181911A1	2015-12-03
WO2012161248A1	2012-11-29
WO2016133222A1	2016-08-25

Foreign References:

JP2013019048A	2013-01-31
JP2008266778A	2008-11-06
JP2015190014A	2015-11-02
JP2001303186A	2001-10-31
JP2006274318A	2006-10-12
JP2013019048A	2013-01-31
JP2009019265A	2009-01-29

Other References: