What is the angular coefficient of Ceramic foundry sand ?
Ceramic foundry sand is a spherical casting sand that can be used as surface sand and molding sand. Many excellent characteristics of ceramic sand come from the morphology of particles. The spherical shape is beneficial for increasing the fluidity and collapsibility of casting sand. The angular coefficient of spherical pearl sand is less than 1.1, while the angular coefficient of silica sand is between 1.2 and 1.45. The advantages of low angular coefficient are as follows:
Firstly, the specific surface area of spherical sand is lower than that of granular casting sand. In casting processes such as coated sand and self hardening sand, the low angle coefficient means that adding less resin can achieve the required molding sand strength.
Secondly, molding sand with a large angular coefficient has granular sharp corners that are easy to break when compressed. After adding resin binder, the gas generation of the molding sand increases. As a result, the molten steel poured into the mold cavity is prone to deformation. That will affect the surface quality of the casting.
Once again, for the sodium silicate no-bake sand casting process, the smaller angular coefficient of ceramic foundry sand is beneficial for increasing the fluidity of the sand. Ceramsite sand has good collapsibility and can improve the efficiency of sand cleaning during casting sand regeneration.
In addition, for thin-walled castings with complex shapes and structures, the angular shape factor of foundry ceramic sand is beneficial for enhancing the molding ability of the sand. Thus it helps to control the accuracy and surface quality of the castings.