Industrial testing of sand-oil mixtures based on natural oils.

Abstract

Rods made of sand-oil mixtures have high strength and gas permeability, pliability, non-hygroscopicity, good fluidity, are easily knocked out of castings, and do not require more binder. The optimal addition of oil to sand-oil rod mixtures is 1,3‒1,5%. To increase the strength in the raw state, up to 2% of clay is added, and for the unhindered exit of the rod from the rod box, an addition of water in an amount of 2,5% is provided. Drying of these rods is carried out at a temperature of 200‒230 °C. Sand-oil rod mixtures are used in the manufacture of rods for critical castings in conditions of small-scale and large-scale production of castings. The technological disadvantage of sand-oil mixtures is the low strength in the raw state, and hence the need to use drivers, that is, they are laid out on special core plates, on which they enter the dryer. The low strength of sand-oil rods in the wet state is explained by the low surface tension of the oil. Due to the scarcity of cotton and linseed oils, it became necessary to replace them with more affordable and cheaper oils that have the ability to form strong films, and which will be competitive with sand-oil mixtures based on pure linseed binders. The aim of the work is to replace cotton and linseed oils with more affordable natural oils (sun-flower and rapeseed) without reducing the physical and mechanical properties in sand-oil core mixtures. The work was carried out by comparing it with a workshop core mixture, and a lignosulfonate-based core mix. The ultimate goal of the research was the possible introduction of a core composition based on sunflower and rapeseed oils into the produc-tion cycle