To obtain good quality metal castings the minimum content of foreign impurities in the metal is important.
Ceramic filters solve two main problems:
- removal of solid particles from the melt;
- elimination of flow turbulence, which due to oxidation of the metal can become a source of inclusions in the castings.
Non-metallic inclusions in molded products reduce strength, ductility, resistance to creep and corrosion, fatigue strength and wear resistance. Large inclusions increase the risk of destruction. They can influence the fluidity and casting properties of the melt. Inclusions can get into the melt in the melting pot as a result of the erosion of refractory materials or the ingress of slag particles. Sometimes oxidation, sulfidation or other reactions can lead to the formation of foreign particles in the melt.