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| The technologies high-integrity castings with fine-grained microstructure and low porosity. | | |
CSIRO says two of its new environmentally friendly technologies can result in stronger conventional die castings.
According to the organisation, the two new technologies, a dynamic gating system and the “ATM runner system”, produce high-integrity castings with fine-grained microstructure and low porosity.
The technologies influence the flow behaviour of the molten metal, the fill pattern of the die and subsequent solidification. They can be used with aluminium and magnesium alloys.
CSIRO says it can take advantage of the high pressure inherent in the die casting process by changing the architecture of the runners and the die cavity gate. This reduces the amount of gas captured during the passage of the molten metal into the die cavity, a factor directly related to porosity.
ATM conditions the melt prior to filling the cavity so that the melt enters the die in a less viscous state, improving melt flow and causing better fusion of separate melt fronts when they meet within the casting.
The improved melt delivery system can be used with existing casting machines, and can reduce the mass of the metal runner, resulting in less metal being wasted.
The researchers say X-ray analysis of test castings made with the dynamic gate showed a significant improvement in density in both thicker and thinner areas of the casting.
Additionally, ATM technology is said to be cheaper to operate than conventional high pressure die casting processes. This development has already been proven by a number of companies in commercial production.
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