Kabushiki Kaisha Kobe Seiko Sho

Kao Corporation

Tomoyuki Sugita

Hideo Fujimoto

Takehiko Ichimoto

Kuniaki Matsui

Keiji Okada

Yuichi Hayashi

A blank for magnetic hard disk and a method for producing the same are provided, characterized in that the attachment or adhesion of a blank of a disk shape to each other can be prevented when such blank is stacked together for disk annealing, thereby improving the productivity of magnetic hard disk, and that the damage of blank surface can be prevented during blanking. Firstly, an aluminium alloy plate is subjected to continuous surface washing process with an etching solution while winding off the aluminium alloy plate in a coil, whereby the oxide film on the surface of the aluminium alloy plate is removed to concurrently deposit insoluble smut on the surface. Then, the aluminium alloy plate after the washing process is pressed for blanking thereof into a blank of a disk shape.

Blank for magnetic hard disk and method for producing same

The present invention relates to a lubricant composition for press-forming an aluminum or aluminum alloy sheet at low temperatures. The composition contains a component (a): 45 to 90% by weight of one or more hydrocarbons selected from the group consisting of mineral oils, synthetic naphthenes, polybutenes, and poly(mono).alpha.-olefins, and component (b): 10 to 45% by weight of one or more C10-C24 linear or branched fatty alcohols. The ester value of the composition is not more than 70, and the kinematic viscosity is less than 20 cSt at 40.degree. C. When this composition is used in forming aluminum or aluminum alloy sheets, enhanced formability can be obtained, and shapes which could not obtained conventionally can be formed.

Lubricant composition for cryogenic forming of aluminum or aluminum

Growing community of inventors

Mooka, Japan

Tomoyuki Sugita