Problems in stainless steel precision casting shell making process

Since the back layer retains the water glass binder, the overall high-temperature strength of the shell is improved. According to the introduction of precision casting manufacturers, the creep resistance is lower than that of silica sol shells, and the dimensional accuracy and shape and position tolerance of cast castings are not as good as those of silica sol shells. The air permeability is not as good as the water glass shell and the silica sol shell, and the high temperature strength of the shell is not as good as the silica sol shell, which is easy to cause waste products.

The quality stability of composite shell castings is worse than that of water glass, but far less than that of silica sol shells. Composite shells cannot use medium-temperature wax materials, and medium-temperature wax cannot be dewaxed with hot water. Because the composite shell uses expensive zircon powder as the surface layer, its shell cost is 4.5 times that of water glass shell. If the back layer uses mullite sand powder, its shell cost is almost the same as that of 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 casting size and surface quality of stainless steel precision casting are higher than other casting methods, and are more complicated than other casting methods.

Castings that are resistant to high temperatures and are not easy to process during the use of the product can be directly cast by investment casting. The stainless steel precision casting process is simply to use fusible materials. The product can be made into a fusible model, which is coated with several layers of special refractory coatings. Melts the model from the shell.

The dimensional accuracy of stainless steel precision casting is high, and the investment casting process of the product is complicated, so there are many factors that directly affect the dimensional accuracy of the casting, such as the change of the wire amount of the shell during the heating and cooling process, and the shrinkage of the alloy. rate and deformation of the casting during solidification.