Most ingots of aluminum wrought alloy have been cast by semi-continuous casting process (DC casting process). DC casting process was invented in 1936. At that time, the casting system already consisted of a water-cooled mold and direct cooling with water. The principles of DC casting have little changed now. However, in order to reduce inverse-segregation and subsurface-band formed underneath the ingot surface, restrict cracks and deformation due to thermal stress and refine cast structure, a number of advanced technologies have been developed. Consequently, the productivity also has improved with increase in the ingot size and the number of ingots in operation at the same time, as well as qualities. This paper describes the elements of solidification which are necessary to understand DC casting and the feature of DC casting process.%アルミニウム展伸材の第1製造工程は「溶解・鋳造」 である。この工程で製造される製品，すなわち鋳塊は展 伸材品質に及ぼす影響が大きく，鋳塊の品質が展伸材の 品質を決めるといっても過言ではない。鋳塊品質は非金 属介在物などの不純物量，形状精度，金属組織などに分 けられ，溶解と溶湯処理の後の鋳造プロセスで最終的に 決定される。
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