Showa Aluminum Corporation

Showa Aluminum Ind. K.k.

Osamu Watanabe

Masashi Sakaguchi

Ryotatsu Otsuka

Hideo Shingu

Kozo Arai

Kenji Tsukamoto

Yasushi Tashiro

Takeshi Otani

Toshio Nishide

To obtain a high-purity aluminum fraction from aluminum containing both eutectic impurities and peritectic impurities, the contents of these impurities in the original aluminum are reduced by melting the original aluminum to obtain molten aluminum, adding boron to the molten aluminum, and rotating a cooling body as immersed in the boron-containing molten aluminum while introducing a cooling fluid to the interior of the body to crystallize high-purity aluminum on the surface of the body. The peritectic impurities react with the boron to form metallic borides, which are centrifugally forced away from the cooling body by the rotation of the body without being incorporated into the aluminum crystallized on the surface of the body. The eutectic impurities are removed from the crystallized aluminum on the surface based on the principle of segregation.

Process for producing high-purity aluminum

An improved cast ingot of aluminum alloy satisfactorily available for rolling operation containing Fe is disclosed which has no fir-tree structure or has only a very small region of fir-tree structure. This cast ingot of aluminum alloy contains calcium in the range of 0.0005 to 0.05% and has a grain size smaller than 150 microns in the region extended inward of a coarse cell phase on the surface area of the cast ingot, particularly in the vicinity of said coarse cell phase. The cast ingot is manufactured by way of the steps of addition of the above amount of calcium to molten aluminum alloy, supplementary addition of 0.005 to 0.1% Ti and 0.0001 to 0.02% B to the molten aluminum alloy and then continuous D.C. casting.

Cast ingot of aluminum alloy available for rolling operation and method

Growing community of inventors

Minoo, Japan

Osamu Watanabe