| 摘要 |
PROBLEM TO BE SOLVED: To provide an Si-containing hot rolled steel sheet having excellent surface properties in such a manner that the generation of red scale is suppressed and surface patterns after pickling is reduced, and especially to provide a high strength hot rolled steel sheet. SOLUTION: The hot rolled steel sheet comprises Si of 0.2 to 2.0%, C of 0.02 to 0.6%, Mn of 0.2 to 3.0%, P of 0.005 to 0.1%, S of≤0.005%, Cr of≤0.3% and of≤0.003% Ca, and in which an Si-containing oxide layer having an Si concentration of not less than two times of that of the whole of the steel sheet is present from the boundary of ferrite/scale in the steel sheet to the surface direction of the steel sheet, and the thickness of the Si-containing oxide layer is≥50% of the whole thickness of the scale. COPYRIGHT: (C)2007,JPO&INPIT
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