| 摘要 |
PROBLEM TO BE SOLVED: To provide a steel material superior in the chemical-conversion treatability of a worked member, and to provide a method for manufacturing the same. SOLUTION: The steel material preferably includes, by mass%, 0.05% or more C, more than 0.7% Si and 0.8% or more Mn. The manufacturing method includes plating the surface of the steel material with a metal of such a slight plating deposition amount as 10 mg/m<SP>2</SP>or less. Thus, manufactured steel material does not cause the lowering of the chemical conversion treatability even when the steel material contains more than 0.7% Si, and can prevent the lowering of the chemical conversion treatability due to working, even when the steel material has been subjected to such working as to exceed 2% by a surface distortion. The metal to be plated is preferably Ni, Cu and Mo. The layer plated with the metal of the slight amount is discontinuously formed so as to partially cover the base steel material, and functions as a cationic point when chemical-conversion crystals deposit on the steel material. Accordingly, dense and fine chemical-conversion crystals can be formed thereon. COPYRIGHT: (C)2010,JPO&INPIT
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