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 slower than that of resin sand process or clay sand process. The effect of modification and grain refinement on the aluminum alloy casting density in LFC is greater than that on resin sand process. Through α Al phase refinement process with 0.2%Ti for aluminum melt, the subversive effect of Sr modification in LFC process is decreased greatly, and the aluminum casting density in LFC process is nearly equal to that in resin sand process. To decrease the porosity of aluminum castings in LFC process, lower density of polystyrene pattern, higher pouring temperature (760～780 ℃) and lower reduced pressure degree (≤20 kPa) should be applied.[