Investigating the Suitability of Local Riverbed Sand as a Mold Material for Foundry Industry: A Comparative Study

The present study aims to assess the viability of using locally available sand (Narmada Riverbed sand (NRS)) for sand casting molds, which can lead to cost and time savings compared to commercial grade silica sand. Physical and mechanical tests of the molds were performed on selected sand samples, and aluminum alloy (A356) was casted. The as cast properties such as porosity, surface roughness (SR), microstructure and phase content was evaluated. The results showed that commercial grade silica sand (CGSS) had the finest quality with the highest grain fineness number (GFN) of 64, while NRS sand was rougher with the lowest GFN of 53. However, all sands exhibited good bonding ability with sodium silicate binders. The study also investigated the impact of different sodium silicate content (6–12%) and time of supply of CO2 gas into the mold on its properties. It is observed that with the increase in the sodium silicate content decreases the mold permeability and increases the strength. The optimum mold properties were observed at 8 wt.% sodium silicate and passing of CO2 gas for a duration of 18 s. Casting of A356 alloy was performed using CGSS and NRS mold. It is observed that NRS can be used for non-ferrous casting in Indian foundries.