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1. (WO2018199328) HIGH STRENGTH STEEL SHEET AND METHOD FOR MANUFACTURING SAME

Pub. No.:    WO/2018/199328    International Application No.:    PCT/JP2018/017311
Publication Date: Fri Nov 02 00:59:59 CET 2018 International Filing Date: Sat Apr 28 01:59:59 CEST 2018
IPC: C22C 38/00
C21D 9/00
C21D 9/46
C22C 38/06
C22C 38/60
Applicants: NIPPON STEEL & SUMITOMO METAL CORPORATION
新日鐵住金株式会社
Inventors: YABU, Shohei
藪 翔平
HAYASHI, Koutarou
林 宏太郎
ABUKAWA, Genki
虻川 玄紀
UENISHI, Akihiro
上西 朗弘
Title: HIGH STRENGTH STEEL SHEET AND METHOD FOR MANUFACTURING SAME
Abstract:
Provided are: a high strength steel sheet suitable as a material for automobile parts, the high strength steel sheet containing a large amount of Mn and having bendability; and a method for manufacturing the high strength steel sheet. This high strength steel sheet having excellent bendability includes a sheet-thickness central portion, and a superficial softened portion formed on one side or both sides of the sheet-thickness central portion, and is characterized in that the average concentration of Mn in the sheet-thickness central portion is greater than 4.0 mass% and less than 10.0 mass%, the thickness of each superficial softened portion is 0.1-30% of the thickness of the sheet, the concentration of Mn in the superficial softened portion is at most 2.5 mass%, and the recrystallization rate of the superficial softened portion is at least 90%.