| The present investigation was undertaken to study the effect of centrifugal force during centrifuged casting on the soundness of Al alloy investment castings, including studies on gating system, pouring temperative, age hardening, etc. The effect were evaluated by the test of specific gravity, microstructure and mechanical properties of Al alloy investment castings. The alloy selected for this investigation were three Al-base alloys: Al-10%Mg, Al-4%Cu & Al-7%Si. These pre-alloyed pigs were melted in electric resistance crucible furnace and each melt was degassed thoroughly with chlorine before pouring. On the basis of these experimental results, the conclusion as follows can be drawn. 1. Down-tapered sprue would be more effective to eliminate the turbulance of metal stream and non-metalic inclusion. 2. Surface smootheness and dimensional accuracy of Al-alloy centrifugal castings were much better than the gravity investment castings, but they were much more effected by finess of investment material than centrifugal force in centrifuged casting of Al-base alloys. 3. The soundness and mechanical properties was promoted with increase of centrifugal force in Al-alloy investment castings. 4. The optimum pouring temperature was found to be 720℃. 5. Age hardening was accelerated with applied centrifugal force up to 50G. |
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