| 摘要 |
PROBLEM TO BE SOLVED: To reduce the development of fine bulged parts and to improve the surface smoothness by regulating the cast block thickness of a blank of aluminum base metallic material of the value not larger than a specified value and applying grinding and non-magnetic preparation treatment. SOLUTION: The thickness of a cast block as the blank constituting the substrate for magnetic disk is regulated to <=400 mm and the substrate having about 0.5-1.5 mm thickness is produced. The blank shearing a belt-like thin plate formed by rolling the cast block of the aluminum base metal into the disk substrate shape, is used and a chamferring process for grinding the shorn corner parts is applied. Successively, after applying process for grinding to the flat surface, a non-magnetic preparation treatment process of plating, etc., a polishing process for specular-polishing and texture process, the substrate for magnetic disk is produced through the non-magnetic substrate layer forming process if necessary. The grinding process is desirable to grind the substrate surface with a grinding stone having about #3000-6000.
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