| 摘要 |
PROBLEM TO BE SOLVED: To provide a steel sheet for heat treatment in which the amount of scale formed on the surface layer of a member after heat treatment or hot press forming is reduced, to provide a cold-rolled steel sheet, and to provide its production method. SOLUTION: In the structure of scale at the time of atmospheric oxidation, a mixed phase of FeO, FeCr<SB>2</SB>O<SB>4</SB>and Fe<SB>2</SB>SiO<SB>4</SB>is allowed to form on the boundary with a base sheet, and a single phase substantially composed of FeO is allowed to form thereon. For this purpose, the content of Si and the content of Cr in the steel, and, if required, the surface roughness of the steel sheet are controlled to fixed ranges, and also, special cleaning treatment of water washing→pickling→alkali cleaning→water washing is performed. COPYRIGHT: (C)2005,JPO&NCIPI
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