STEEL SHEET - NIPPON STEEL CORP

Title:

STEEL SHEET

Document Type and Number:

WIPO Patent Application WO/2020/262651

Kind Code:

A1

Abstract:

A steel sheet which has a metal structure that contains, in terms of volume fraction, 95% or more of tempered martensite and a total of 5% or less of one or more structures selected from among ferrite, pearlite, bainite, as-quenched martensite and residual austenite. This steel sheet has a tensile strength of 1,100 MPa or more; the standard deviation of the Vickers hardness is 30 or less as measured under a load of 9.8 N at 30 points in a 300 μm square area that is centered at the position of t/2, where t is the sheet thickness, in a cross-section of the steel sheet 10, said cross-section being parallel to the sheet thickness direction; and if nanohardness is measured under a maximum load of 1 mN at 100 points in a 100 μm square area that is centered at the position of t/2, the ratio of the measurement points that have a nanohardness difference of 3 GPa or more from 8 adjacent measurement points is 10% or less. This steel sheet has high strength and excellent collision resistance characteristics.

Inventors:

NAKANO KATSUYA (JP)
TAKEDA KENGO (JP)
KAWATA HIROYUKI (JP)
UENISHI AKIHIRO (JP)
SUZUKI YUYA (JP)

Application Number:

PCT/JP2020/025352

Publication Date:

December 30, 2020

Filing Date:

June 26, 2020

Export Citation:

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Assignee:

NIPPON STEEL CORP (JP)

International Classes:

C21D9/46; C22C38/00; C22C38/60

Domestic Patent References:

WO2014077294A1	2014-05-22
WO2009110607A1	2009-09-11

Foreign References:

JP2011179030A	2011-09-15
JP2016084520A	2016-05-19
JP2014019926A	2014-02-03
JP2013227614A	2013-11-07
JP2015117403A	2015-06-25
JP2009215571A	2009-09-24

Other References: