1.Since the back layer retains the water glass binder, the overall high temperature strength of the shell. The creep resistance is lower than that of the silica sol shell, and the dimensional accuracy and shape tolerance of the cast castings are not as good as that of the silica sol shell.
2.The air permeability is not as good as that of the water glass type shell and the silica sol type shell. The high temperature strength of the type shell is not as good as that of the silica sol type shell, which is easy to cause waste.
3.The quality stability of composite shell castings is worse than that of water glass, but far inferior to silica sol shells.
4.The compound shell can not use medium temperature wax. Medium temperature wax cannot be dewaxed with hot water.
5.Because the composite shell uses high-priced zircon powder as the surface layer, the shell cost is 4.5 times that of the water glass shell. If the back layer is made of mullite sand powder, the shell cost is almost the same as that of the silica sol shell. , The advantage of its low cost is not obvious.
The alloy shrinkage rate of stainless steel precision casting and the deformation of its castings in the process of stainless steel precision casting. Although the dimensional accuracy of ordinary investment castings is relatively high, it needs to be improved in order to achieve consistency. The size and surface quality of stainless steel precision casting castings are higher than other casting methods, and more complicated than other casting methods. The products are resistant to high temperatures during use and are not easy to process. The products can be directly used. Cast by investment casting.
Post time: Apr-29-2021