Automation in foundry/casting industry

In the present study, the cooling curve analysis or thermal analysis technique during solidification of ferrous and non-ferrous alloys was used. For ferrous alloy, the temperature recording equipment IEEE 488 fitted with an Interface Scanner 740 and a GPIB (General Purpose Interface Bus) programme was used to obtain a continuous record of the temperature during solidification of the casting. The equipment also plotted the temperatures versus time cooling curves automatically. For non-ferrous alloy, the set-up for thermal analysis consisted of hot junctions and cold junctions, both feeding in to a 2-pen recorder. An Oxford (3000), 2-pen horizontal potentiometric recorder was used for calibrating the cooling curves during freezing of the alloy. Cast iron (a ferrous alloy) containing 4.3% C is a eutectic alloy, which melts or freezes (like a pure metal) at a fixed temperature of 1130/spl deg/C, while aluminium-silicon (a non-ferrous alloy) containing about 12% Si is a eutectic alloy, which melts or freezes at a fixed temperature of 577/spl deg/C. The cooling curves during freezing showed the eutectic temperature as well as the 'under-cooling' i.e. the deviation curve from this equilibrium position. Experiments in the present study showed that the more the under-cooling, the more refinement of the structures and thus, the more improvement of the properties in the cast product. Therefore, by looking through the amount of deviation/under-cooling of the cooling curves, it is possible to forecast the expected structural modifications and hence, the resulting properties of the products made by casting process. This technique, thus avoids the various lengthy time consuming and expensive steps used in determining the microstructure and properties of the cast product.