Porosity of aluminum alloy in lost foam casting process

The effects of modification, grain refinement, polystyrene pattern, pouring temperature and reduced pressure degree on aluminum alloy porosity in lost foam casting (LFC) process were studied. The results show that the solidification rate of LFC process is lower than that of resin sand process or clay sand process. The effect of modification and grain refinement on the Al alloy casting density in LFC is greater than that on resin sand process. Through alpha -Al phase refinement process with 0.2% Ti for Al melt, the subversive effect of Sr modification in LFC process is decreased greatly, and the Al casting density in LFC process is nearly equal to that in resin sand process. To decrease the porosity of Al castings in LFC process, lower density of polystyrene pattern, higher pouring temperature (760-780 deg C) and lower reduced pressure degree ( < =20 kPa) should be applied.