Erosion phenomena in sand moulds

Authors studied the erosion phenomena in sand moulds poured with cast iron. The study comprises an evaluation of erosion resistance of the three sands: green sand, sand bonded with inorganic or organic binder. It was concluded that the most resistant is the classic green sand with the addition of 5 % coal dust. Resistance of the sand with organic binder is generally weak and depends on kind of used raisin. Special attention was paid to the sands with no organic binder water glass and phosphate. It was found that their resistance depends on dehydratation conditions. When the mould is stored in law humidity of atmosphere the very strong erosion can be expected. It results from the micro fractures in the bridges of binders, joining the grains of the sable. This phenomena facilitates the tearing away of fragments of sand from the surface.