The particle composition of Tongliao casting sand is mainly represented by the screen sizes with high residue amounts and the sizes before and after them. While its wet strength and permeability are not major concerns, it is more important to enhance the sand's strength and reduce the amount of binder. Below is a brief introduction to the particle size and permeability of Tongliao casting sand.

On one hand, the permeability of the casting sand should not be too high to prevent the metal liquid from easily渗透 into the pores between the sand grains. Small parts of manually molded products often have many holes and typically use surface sand. This can make the sand grains thinner, and the permeability of the surface sand is usually around 40-60.

Individual sand particles have a diameter of approximately 70/140 mesh, with a porosity typically ranging between 60 and 90. Sand molds used for high-density casting should be relatively dense and possess high permeability, with most having diameters of 50/140 or 140/50 mesh, and the porosity is more concentrated between 100-140 mesh.

For instance, the core sizes used by many foundry sand producers are larger than the molding sand. For example, the particle size of the cylinder core for automotive engines is 50/100 mesh. Over a long production process, a large amount of core sand gets mixed into the foundry sand, causing the molding sand to become thickened.

Therefore, some foundry sand producers offer sand with permeability as high as 160 or even 200. Without shot blasting, the surface of the castings will become rough, and even partial mechanical shot blasting may occur.

With the above introduction, I believe everyone has a better understanding of the particle size and permeability of Tongliao casting sand. If you have any other questions or suggestions, please feel free to contact our company directly.