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1. (WO2018105510) HIGH MN STEEL SHEET AND METHOD FOR PRODUCING SAME

Pub. No.:    WO/2018/105510    International Application No.:    PCT/JP2017/043245
Publication Date: Fri Jun 15 01:59:59 CEST 2018 International Filing Date: Sat Dec 02 00:59:59 CET 2017
IPC: C22C 38/00
C21D 8/02
C22C 38/58
Applicants: JFE STEEL CORPORATION
JFEスチール株式会社
Inventors: UEDA Keiji
植田 圭治
HASE Kazukuni
長谷 和邦
Title: HIGH MN STEEL SHEET AND METHOD FOR PRODUCING SAME
Abstract:
Provided are a high Mn steel sheet and a method for producing this high Mn steel sheet. This high Mn steel sheet has a component composition which contains, in mass%, 0.20-0.70% of C, 0.05-1.0% of Si, 15-30% of Mn, 0.028% or less of P, 0.02% or less of S, 0.01-0.1% of Al, 0.5-7.0% of Cr, 0.03-0.30% of Ni and 0.0010-0.0200% of N, while containing one or more of 0.003-0.030% of Nb, 0.03-0.10% V and 0.003-0.040% of Ti, with the balance made up of Fe and unavoidable impurities. With respect to this high Mn steel sheet, the microstructure at 0.5 mm below the steel sheet surface has a matrix phase of austenite; and 25% or more of the austenite in terms of area ratio has a circle-equivalent diameter of 10 μm or more, while having an aspect ratio of the length to the breadth of 3 or more.