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Steel Investment Casting Process – Ningbo Investment Casting Co., Ltd

By Li Chenyu / hcfire360 July 2021

1. The first step in the Steel Investment Casting Process is to produce a wax replica of the desired part. This is accomplished by injecting wax into an aluminum die cavity.

Automatic Wax Injection

2. After wax injection, the wax replica is removed from the injection tool. The wax patterns are cleaned the excess rough edges, inspected for tolerance and then cleaned for assembly.

Wax Pattern  Removal

3. Wax eplicas also called wax patterns are “wax welded” to a central sprue or cluster to facilitate pouring, looks like a “wax tree”. Many replicas are attached to sprues for increased efficiency, and the reasonable quantity attach in the sprue could ensure the castings quality and save cost.

Wax Pattern Assembly

4. The assembled sprue is then dipped or “invested” in into a ceramic slurry. After draining, the sprue is then coated or “stuccoed” with a fine ceramic sand. This process is repeated several times using progressively coarser grades of ceramic material to “build” sufficient “shell” strength.

Automatic Shell Building

5. The shell built sprue is then de-waxed by rapidly heating in an autoclave leaving behind the perfect shell cavity.


6. The shells are then fired at 1600° to 2000° in furnace. This cures the shells interior into smooth, hard and strong ceramic material. The other reason is to remove the moisture in the shell for a better surface finish of the castings.

Preheating Shell Furnace

7. The hot sprues are then removed from the furnace and poured immediately. The poured shells are then set aside to cool.


8. When cool the shell material is stripped away from the sprue. Parts are then cut from the sprue.
Cooled To Cut Pouring Gate
If you have any steel casting parts, please Contact Us  or contact us by sales@nbinvestmentcasting.com for best price.
Ningbo Investment Casting Co., Ltd
Please see below detail Steel Investment Casting production process in our steel foundry.