US Patent 7182824 Method of manufacturing zinc alloy ingot

A molten zinc alloy, which contains 4–22 mass % Al, 1–7 mass % Mg and optionally one ore more of Ti, B and Si at very small ratios, is held at a temperature Th higher than (a solidification-beginning temperature Ts.b.+85° C.) for homogenization, and then cooled down to a temperature Tc equal to (Ts.b.+20–65° C.). After the molten alloy is poured in a mold, it is naturally cooled and solidified to an ingot, while its upper part is being heated. Once an upper surface of the zinc alloy in the mold begins to solidify, it is optionally cooled with water. The produced ingot has a structure without cracks or cavities, so that it is safely fed to a molten pool for replenishment.