Casting process of water glass casting

  Water glass casting is also known as water glass casting. The casting process is very similar to investment casting (i.e. lost wax investment casting). It is a shell casting technology with sodium silicate as binder. The process provides a far superior surface finish and dimensional accuracy to achieve through sand casting. More complex shapes can be achieved.

It is especially suitable for large castings, and the production cost is lower. The main raw material is steel.

Water glass casting technology from Russia. It is one of the most commonly used investment casting processes in China. About 75% of the foundries focus on the sodium silicate casting business. The rest are silica sol casting factories.

 Benefits of water glass casting

1. Surface finish is better than sand casting.

2. The dimensional accuracy is higher than that of sand casting.

3. Implement the more complex parts.

4. Compared with the traditional investment casting method, it is suitable for larger parts.

5. Cheaper than investment casting.

6. The construction period is shorter than investment casting.

7. More metal options.

8. Environmental advantages. (Wax is fully recyclable.)

 Water Glass Investment Casting Process

The wax-loss method differs from water glass casting only in the way the wax is taken from the ceramic mold:

Investment casting uses a high temperature autoclave to melt wax while. In water glass casting, the mold is immersed in hot water to remove wax. The wax then melts from the mold and floats on the surface of the water. This allows it to be skimmed off and used for wax purposes.

Obviously, this also offers environmental advantages and the wax is fully recyclable.

 Step 1: Wax injection

For each desired casting, melted wax is injected into the mold to produce a wax pattern for the casting. The wax mold is made of aluminum and has been sized according to the shrinkage of the wax and metal used. Wax moulds range from simple two-piece moulds to multi-chamber automated moulds and complex moulds with water-soluble or ceramic cores.

 Step 2: Wax

Once the wax mold has cooled and stabilized to a stable size and shape. They will be mounted on spouts or trees. The gate, also made of wax, contains all necessary gates, runners, and supports to adequately supply the parts during casting.

 Step 3: Make the shell

Wax gates are now "invested" in ceramics. This forms the mold into which the metal is to be injected. Ceramics consist of two parts. The surface is a liquid mud covered with dry sand. Each sprue is covered with many layers of slurry and sand. Until the ceramic shell is thick enough to withstand during casting. The shell building time is generally 1 day. It can also take two days to a week for the shells to dry completely.

 Step 4: Dewaxing

Once the shell is completely dry, the shell can be fired to remove any remaining wax residue and solidify the ceramic shell. After the shells are fired, they can be poured.

 Step 5: Pouring

Before casting, place the shell in the oven to preheat. When the shell is at the right temperature, the molten metal has been prepared and qualified. Remove the shell from the oven and pour the metal into the shell.

 Step 6: Finishing

The shell is finished by hammering, medium blasting, vibration, water jet, or chemical dissolution (sometimes with liquid nitrogen). The gate is cut off and recycled. The casting can then be cleaned to remove traces of the casting process. Usually by grinding.