Effects of Using Fins and Carboceramics on the Solidification Characteristics of Aluminum Casting Alloys?
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Abstract
Recent studies have shown that using the cooling fins is one of the most appropriate methods to eliminate the shrinkage porosities in the castings. In fact, Fins play the role of heat exchangers during the solidification and their usage is the same as that of chills. The cooling effect of fins is directly related to their geometry. Also the effect of fin on decreasing the time of local freezing is a function of metal’s thermal conductivity, mould thermal conduction, superheating and fin dimensions. In this research, the effect of three types of fins on local solidification time of a casting of A356 and 6069 alloys as well as the effect of moisture content on cooling rate of sand moulds made of carboceramics have been studied. Results indicate that fin affects severely on solidification time and this influence is more severe in castings produced in moulding materials such as carboceramics which can absorb more moisture. The results show that carboceramics as a new refractory material decrease the solidification time significantly. This is particularly evident when the fins were used. Generally, using fins and carboceramics decrease the solidification time down to 45%. This is good news for casting industry in which the mechanical properties can be easily improved using simple ways.
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