The casting expansion defects can be effectively prevented by using part of the ceramic foundry sand in the molding sand and core sand.

In recent years, some manufacturers of coated sand in our country have added some sapphire sand in the raw material sand, so that the shell mold and shell core can have the properties of high temperature resistance, low expansion, easy collapse, high strength and low gas generation. For the core with particularly complex shape, it can also solve the problem that sand shooting is not easy to compact.

In order to meet the requirement of light weight, the problems such as misrun and cold lap can be effectively solved by adding some ceramic foundry sand into the face sand in the production of thin wall iron castings, and the overcooling structure can be avoided.

In the aspect of modeling, using ceramic foundry sand instead of silica sand has the following advantages.

1.The content of dust in the atmosphere of workplace has been greatly reduced, especially the siliceous dust, which will be more and more concerned in the future.

2.The raw sand consumption per ton of casting can be greatly reduced, thus saving resources.

3.Because the fluidity of sand is good, under the same condition of compaction, the compactness of mold and core is improved, and the gas permeability is still good, which is helpful to improve the quality of casting.

4.The drawing property of molding sand can be obviously improved, which can reduce the draft of pattern and drop of sand, and help to improve the dimensional accuracy and surface quality of castings.