Patent ID: 8870999

Claim:
A method of casting an aluminium alloy comprising: filling a pour ladle with a liquid hypoeutectic aluminum-silicon alloy; cooling the liquid hypoeutectic aluminum-silicon alloy without the presence of an inerting gas in the ladle from the bottom of the ladle to the top of the ladle to a temperature below the solidus temperature of the hypoeutectic aluminum-silicon alloy in order to facilitate an upward migration of hydrogen gas within the hypoeutectic aluminum-silicon alloy; heating the cooled hypoeutectic aluminum-silicon alloy to a temperature above the liquidus temperature of the hypoeutectic aluminum-silicon alloy from the top of the ladle to the bottom of the ladle such that any remaining hydrogen gas that was subject to upward migration is liberated as the hypoeutectic aluminum-silicon alloy liquifies; applying a vacuum while the hypoeutectic aluminum-silicon alloy is being cooled and heated within the ladle; pouring the liquified hypoeutectic aluminum-silicon alloy into a casting mold; and cooling the liquified hypoeutectic aluminum-silicon alloy to below its solidus temperature.