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1. (WO2017037827) STEEL SHEET

Pub. No.:    WO/2017/037827    International Application No.:    PCT/JP2015/074638
Publication Date: Fri Mar 10 00:59:59 CET 2017 International Filing Date: Tue Sep 01 01:59:59 CEST 2015
IPC: C22C 38/00
C21D 9/46
C22C 38/58
Applicants: NIPPON STEEL & SUMITOMO METAL CORPORATION
新日鐵住金株式会社
Inventors: OKAMOTO, Riki
岡本 力
KAWATA, Hiroyuki
川田 裕之
AZUMA, Masafumi
東 昌史
UENISHI, Akihiro
上西 朗弘
MARUYAMA, Naoki
丸山 直紀
Title: STEEL SHEET
Abstract:
A steel sheet has a specified chemical composition, and has a steel structure comprising, in area%, 20 to 95% of first martensite in which at least two iron carbide grains each having an equivalent circle diameter of 2 to 500 nm are contained in each lath, 15% or less of ferrite, 15% or less of retained austenite, and a remainder made up by bainite and/or second martensite in which less than 2 iron carbide grains each having an equivalent circle diameter of 2 to 500 nm are contained in each lath. The total areal fraction of ND//<111> direction grains and ND//<100> direction grains in the steel sheet is 40% or less. The content of solid solution C in the steel sheet is 0.44 ppm or more.