Compared with ordinary, the solidification characteristics of are also different, mainly in the following aspects:
1) Compared with ordinary sand casting, the cooling and solidification speed of lost foam casting is much slower. The vacuum degree has no significant effect on the cooling and solidification rate of castings;
2) The mold of lost foam casting has good stiffness. Generally, the mold will not expand in volume during pouring. In this way, the self feeding ability of castings is enhanced, so that the shrinkage cavity and shrinkage porosity tendency of lost foam castings are greatly reduced;
3) The cooling speed of vacuum lost foam casting is slow, the temperature difference entering the plastic transformation is small, and the resistance of the mold is much smaller than that of the general clay sand mold. Therefore, compared with other casting methods, the forming stress and hot crack tendency of the casting are much higher.