Aluminum casting method with helium insertion

摘要

Helium gas at ambient pressure is inserted into an expendable mold at a fill tube or other port exiting the bottom of the mold. The helium displaces atmospheric air in the mold cavity, and the displaced air exits the cavity through the fill tube. When the air in the mold cavity and fill tube has been completely displaced by the helium, the fill tube is submerged in molten aluminum, and the aluminum is drawn into the mold cavity through the fill tube to form a casting having significantly reduced oxide inclusions and significantly improved fatigue strength.