| 摘要 |
PURPOSE: To provide a thin steel sheet for a floppy disk shutter which is produced at a low cost, is hardly flawed, is inconspicuous in flaws and is excellent in scratching resistance by forming a a projecting part having a specified dimension on the surface at a specified density. CONSTITUTION: On the surface of a thin steel sheet, a projecting part whose length in the rolling direction is regulated to >=0.5mm, whose width in the direction perpendicular to the rolling direction is regulated to 5 to 250μm and whose height is regulated to 2 to 15μm is formed by >=1 pieces per mm<2> . The formation of the same projecting part can be obtd. by subjecting the thin sheet material to finish cold rolling by using a rolling roll whose surface is ground by a magnet having suitable meshes. Moreover, the metallic structure of the thin steel sheet is preferably formed of <=10vol.% martensite content, and the balance substantially austenitic phase. By using this thin steel sheet, the floppy disk shutter excellent in scratching resistance can inexpensively be obtd.
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