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1. (WO2018105003) HIGH STRENGTH STEEL SHEET

Pub. No.:    WO/2018/105003    International Application No.:    PCT/JP2016/086060
Publication Date: Fri Jun 15 01:59:59 CEST 2018 International Filing Date: Tue Dec 06 00:59:59 CET 2016
IPC: C22C 38/00
C22C 38/60
C21D 9/46
Applicants: NIPPON STEEL & SUMITOMO METAL CORPORATION
新日鐵住金株式会社
Inventors: SANO, Kohichi
佐野 幸一
OKAMOTO, Riki
岡本 力
Title: HIGH STRENGTH STEEL SHEET
Abstract:
A high strength steel sheet wherein: the chemical composition is, in mass%, C: 0.10-0.24%, Mn: 3.50-12.00%, Si: 0.005-5.00%, Al: 0.005-5.00%, P: 0.15% or less, S: 0.030% or less, N: 0.020% or less, O: 0.010% or less, Cr: 0-5.00%, Mo: 0-5.00%, Ni: 0-5.00%, Cu: 0-5.00%, Nb: 0-0.50%, Ti: 0-0.50%, W: 0-0.50%, B: 0-0.010%, Ca: 0-0.05%, Mg: 0-0.05%, Zr: 0-0.05%, REM: 0-0.05%, Sb: 0-0.50%, Sn: 0-0.50%, As: 0-0.05%, V: 0-2.0%, balance: Fe and impurities; and the metal structure at the ¼ sheet thickness position is, in area%, retained austenite: 10.0-55.0%, high temperature tempered martensite: 30.0-75.0%, low temperature tempered martensite: 15.0-60.0%, the balance being fresh martensite: 0-10.0%, pearlite: 0-5.0% and bainite: 0-5.0%.