The aim of this work is the study and the development of a specific testing methodology for evaluating the fluidity of aluminium foundry alloys. This method, based on the Archimedean spiral, is intended to be easily and practically used in foundry. The necessary device to perform the tests is made by sand moulds and it reproduces the Archimedean spiral cavity where the molten alloy is poured. An A356 alloy has been used and a series of tests has been carried out with the purpose to make the methodology operative according to a standardized operating sequence. The focus has been the maximum repeatability of the results. Fluidity tests, carried out at different molten metal temperature, have been performed both on the laboratory scale and within a foundry plant, and they have concerned either the EN standard alloy and the grain refined and Sr-modified one. Finally, a specific experimental test has been numerically studied by means of a commercial process simulation software. The obtained results suggest to increase appropriately the initial temperature of the bath to improve the repeatability of the experiments. Furthermore, thin section of the spiral cavity induces high cooling rates able to prevail over the effects of preliminary treatments of the molten bath.
Fluidity of aluminium foundry alloys: Development of a testing procedure
CALIARI, DANIELE;TIMELLI, GIULIO;BONOLLO, FRANCO;
2015
Abstract
The aim of this work is the study and the development of a specific testing methodology for evaluating the fluidity of aluminium foundry alloys. This method, based on the Archimedean spiral, is intended to be easily and practically used in foundry. The necessary device to perform the tests is made by sand moulds and it reproduces the Archimedean spiral cavity where the molten alloy is poured. An A356 alloy has been used and a series of tests has been carried out with the purpose to make the methodology operative according to a standardized operating sequence. The focus has been the maximum repeatability of the results. Fluidity tests, carried out at different molten metal temperature, have been performed both on the laboratory scale and within a foundry plant, and they have concerned either the EN standard alloy and the grain refined and Sr-modified one. Finally, a specific experimental test has been numerically studied by means of a commercial process simulation software. The obtained results suggest to increase appropriately the initial temperature of the bath to improve the repeatability of the experiments. Furthermore, thin section of the spiral cavity induces high cooling rates able to prevail over the effects of preliminary treatments of the molten bath.
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