Lost foam casting apparatus for reducing porosity and inclusions in metal castings

摘要

Apparatus for the gravity-cast, bottom-fill, "lost foam" casting of metal castings, including a fugitive, pyrolizable pattern (for forming a casting cavity), and a hollow sprue (for conducting melt to the casting cavity) embedded in a bed of loose sand. The sprue is free from pyrolyzable foam and conducts melt from above the pattern to a gating system supplying melt to the pattern. The sprue is constructed so as to cause the melt to approach the gating system from beneath and keep any pyrolysis products from entering the sprue.