STEEL SHEET - NIPPON STEEL CORP

Title:

STEEL SHEET

Document Type and Number:

WIPO Patent Application WO/2020/262652

Kind Code:

A1

Abstract:

Provided is a steel sheet wherein: the metal structure thereof, by volume, contains at least 85% tempered martensite, at least 5% and less than 15% retained austenite, and less than 10% ferrite, pearlite, bainite and as-quenched martensite in total; when the Mn content and the C content in the retained austenite are respectively MnA and CA, and the Mn content and the C content in a matrix are respectively MnM and CM, the following formulas (1)-(3) are satisfied; the number of carbides having a circle-equivalent radius of at least 0.1 μm is no more than 100 per 20,000 μm2; and the tensile strength of the steel sheet is at least 1,100 MPa. This steel sheet is highly moldable, and has excellent impact resistance.　Formula (1): MnA/MnM≥1.2 Formula (2): CA/CM≤5.0 Formula (3):CA≤1.0

Inventors:

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

Application Number:

PCT/JP2020/025353

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:

WO2016163468A1	2016-10-13
WO2018055695A1	2018-03-29
WO2017068757A1	2017-04-27
WO2017009938A1	2017-01-19
WO2016021193A1	2016-02-11
WO2018073919A1	2018-04-26

Foreign References:

JP2019039037A	2019-03-14
JP2019014933A	2019-01-31
JP2017053001A	2017-03-16
JP2015151576A	2015-08-24
JP2011202207A	2011-10-13
JP2013072101A	2013-04-22

Other References: