Investigation on the Influence of Different Additives on Properties of Green Sand Mould
Green sand mixtures which are used for moulding purposes in foundry industries should possess sufficient green compression strength, flowability, toughness and air permeability. Usually, the aforementioned properties for a particular casting differ due to variation in composition of the moulding sand mixtures, sand grain shape and size, bonding capacity of the binder, type and quantity of additives used, etc. The present work focuses on the effect of various additives namely, camphor powder, coconut shell ash, mixture of camphor powder and coconut shell ash at diverse proportions on permeability and green compression strength of the sand moulds. The quantity of the aforementioned additives for experimentation was varied from 0.5 to 3.5 wt. It was found that the mould's permeability increased on addition of 1 wt. additives for all cases. Similarly, the optimum quantity of additives that needs to be added to the sand mixtures for enhancing green compression strength was found to be 2 wt. Among all the additives used for improving the mould's permeability, substitution of camphor exhibited best results. The green compression strength was found to be highest for the coconut shell ash containing sand mould. The moulding sand containing a combination of camphor powder and coconut shell ash between 1 to 2 wt. exhibited fine mould permeability along with sufficient green strength.