Airtight aluminum alloy casting and its manufacturing method.

摘要

An aluminum alloy casting comprising 4.0 to 13.0% of Si, 4.5% or below of Cu, 1.5% or below of Mg, and the rest of Al in weight ratio is produced by a production method which adds a metallic hydride to a molten aluminum alloy for casting at a temperature of liquidus line or above. This method makes the shape of pores generated in the casting circular and fine, and an average crystal grain diameter to be 1/3 or below of a thickness of the casting, thereby, an aluminum alloy casting having excellent airtightness can be produced.