Why Silica Sol for Investment Casting?
Silica sol is a kind of milky colloid. Since the colloid grains are minute (10-20micrometer) and have relatively large surface area, so they do not affect the natural color of materials to be covered. Silica sol is mutually soluble with water , but not with organic solvent. It can dissolve in a solution of alcohol or water mixed in any ratio. The distinguished feature is that with low viscosity, it can soak the places where water soaks, therefore, silica sol presents excellent dispersion and permeability when being mixed with other substances. When the moisture contained in silica sol is evaporated, the colloid grains firmly adhere to the material surface and the combination of silicon and oxygen is then formed between grains. It is a good adhesive. That is the main function of silica sol as an molding adhesive for stainless steel investment casting.
Silica sol castings are mainly used for products with high corrosion resistance and precision dimensions, since silica sol steel casting can have much better surface quality and less geometrical deviation of dimensions. The main silica sol steel castings we ever made include meat grinder parts, valve castings, pump castings, marine hardware, and furniture decoration etc.
Silica Sol Casting in Our Foundry
In our foundry, all the stainless steel castings are produced in solica sol casting. Stainless steel 304 and stainless steel 316 are the main material grades for solical sol castings. We can produce unit weight 0.01kg-50kg and mainly exported to international market like USA, Australia, Canada, South Africa, ect. Silica sol casting can be carried out for further machining.
Capability of Silica Sol Casting
- Liner tolerance of silica sol castings can be controlled with ±0.1mm, and the surface finish is Ra6.3.
- Min. weight 0.01kg, Max. weight 50kg.
- Cast min. hole: Φ2mm
- Cast min. round corner: R0.1mm
- Cast min thickness: 0.7mm
Silica Sol Casting vs Water Glass Casting
The silica sol investment castings have better dimensions and surface quality, but just more expensive than water glass casting. Cost of solica sol casting is almost twice than the cost of water glass casting. Both silica sol casting and water glass casting belong to investment casting or lost wax casting. So process of silica sol casting is almost the same as water glass casting. But silica sol investment casting process uses silica sol zircon sand as the molding material, which can stand temperature up to 2000 degree. Below are the main differences between solica sol casting and water glass casting.
|Process||Silica sol casting||Water glass casting|
|Machining||No or less machining||More machining|
|Material||Stainless steel||Carbon steel & alloy steel|