Precision casting technology continues to mature, but needs to be improved

Silica sol shell process. The silica sol shell-making process is widely used in the more advanced foundry industry of internal combustion engine parts. The coating used in this method has good stability, does not require a chemical hardening process, is resistant to high temperature, and has better resistance to deformation. However, the disadvantage of this technology is that the wettability of the wax mold is poor. Although it can be improved by adding surfactants, it will increase the investment to a certain extent.

Water glass shell process. The water glass shell process was invented very early, and my country also introduced this technology from the Soviet Union in the 1950s and 1960s. The technology has low cost, relatively simple operation, and low requirements on raw materials, so it is widely used in stainless steel precision casting. However, the biggest problem of this technology compared to the silica sol shell making process is that the surface quality of the resulting castings is general and the dimensional accuracy is low. However, due to its cost advantage, my country still uses this technology in some civilian or low-precision internal combustion engines. Since the introduction of this technology, Chinese researchers have made great improvements to it, mainly in the aspects of improving shell coatings, optimizing hardeners, and using composite shells.