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1. (WO2017017961) COLD ROLLED STEEL SHEET, PLATED STEEL SHEET AND METHODS FOR PRODUCING SAME

Pub. No.:    WO/2017/017961    International Application No.:    PCT/JP2016/003509
Publication Date: Fri Feb 03 00:59:59 CET 2017 International Filing Date: Fri Jul 29 01:59:59 CEST 2016
IPC: C22C 38/00
C21D 9/46
C22C 38/06
C22C 38/60
Applicants: JFE STEEL CORPORATION
JFEスチール株式会社
Inventors: KAWAMURA, Kenji
河村 健二
KOHSAKA, Noriaki
▲高▼坂 典晃
FUNAKAWA, Yoshimasa
船川 義正
AOYAMA, Mai
青山 麻衣
SUZUKI, Yoshitsugu
鈴木 善継
Title: COLD ROLLED STEEL SHEET, PLATED STEEL SHEET AND METHODS FOR PRODUCING SAME
Abstract:
The present invention provides a cold rolled steel sheet suitable for producing a high strength hot dip galvanized steel sheet having excellent plating adhesion and surface appearance, and a method for producing the cold rolled steel sheet. This cold rolled steel sheet has a specific constituent composition, and the concentration of Mn at a surface layer of the steel sheet satisfies formula (1) and formula (2). 8 ≤ (Cp/Cc) × Mn (1) (Cmin/Cc) × Mn ≤ 2.5 (2) Cp denotes the maximum Mn concentration in a region up to a depth of 0.5 µm in the sheet thickness direction from a surface of the steel sheet, Cc denotes the average Mn concentration in a region between a depth of 5 µm in the sheet thickness direction from a surface of the steel sheet and a depth of 5 µm in the sheet thickness direction from the opposite surface of the steel sheet, Cmin denotes the minimum Mn concentration in a region at a depth of between 0.5 µm and 5 µm in the sheet thickness direction from a surface of the steel sheet, and Mn denotes the content of Mn (mass%)