Change in Porosity of A356 by Holding Time and Its Effect on Mechanical Properties
Uludag, Muhammet and Cetin, Remzi and Gemi, Lokman and Dispinar, Derya
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Abstract
In most of the practical casting operations, it is important to be able
to cast large number of part with one single melt. Therefore, when
quantity of the charge and melting crucible is increased, during casting
process, the liquid is led to settle for a long period of time. In this
work, 10kg charge of A356 was melted at 750 degrees C and held for
240min. A sand mold with different thickness was cast at 30, 60, 120,
and 240min of holding time of the liquid, before and after degassing
conditionss. Melt quality was measured by reduced pressure test, and pore
size and number were measured at each cast part. A correlation between
bifilm index and tensile properties was established. It was found that
melt quality was decreased with increased holding time and pore
formation was enhanced linearly. Additionally, mechanical properties of
the alloy were decreased with decreased melt quality and increased pore
formation due to holding time of the liquid.... Show more Show less