Material is QT450

At present, many processing factories of EPC casting crafts have changed the first second layers into mixed quartz powder, zirconium corundum powder silica sol shell. The back layer is still processed by the original sodium silicate shell process. It is an improvement measure to combine the high quality process performance of silica sol shell with the advantages of low cost short cycle of sodium silicate. Compared with the sodium silicate shell, the casting process performance has been greatly improved, the roughness is reduced, the surface defects are reduced, the failure rate is reduced. The production cycle is similar to that of sodium silicate shell.

Key problems

(1) Because sodium silicate adhesive is preserved in the cold grid back layer of EPC casting, the overall high-temperature compressive strength stress relaxation resistance of the shell are lower than that of silica sol shell. The specification precision dimension tolerance of casting parts of aluminum alloy casting manufacturer for casting TV support are lower than that of silica gel shell.

(2) The permeability of the shell can be compared with sodium silicate shell silica sol shell, the high temperature compressive strength of the shell is as good as silica sol shell, which is easy to lead to waste.

(3) The quality reliability of composite shell casting is better than that of sodium silicate, but it is as good as that of silica sol shell.

(4) The cost of composite shell is 4.5 times higher than that of sodium silicate shell because the expensive mixed quartz powder is selected as the whole surface layer. If zircon corundum sand powder is selected as the back layer, the cost of composite shell is the same as that of silica sol shell, the advantage of low cost is significant.