For decades the best practice was to use centrifugal casting, that provide good quality in respect to voids , porosity   also avoid quick cooling

Hi Nagasai, although you have not mentioned the type of material (plastic/metal), I would say using a better casting setup (play with temperature, cooling rate, and vacuum) to find a better setup that can mitigate the porosity and crack.

Thank you for your suggestion.

Porosity shows usually that something in your cast evaporates. So look for the vapour pressure of the metals and impurities in your alloy. You could reduce the pores also by raising the pressure under which you cast. And finally of course try to cast with the lowest possible temperature. This will also reduce the cracks.

I agree with all recommendations above. Cracks can be produced by high level of residual stresses. Residual stresses are produced in your case by high temperature gradients. Avoid quick cooling is a good advice.

Prof. Paul Barsanescu

Technical Univ. "Gheorghe Asachi" of Iasi

Strength of Materials Laboratory

I'm glad to thank you all for your valuable suggestions.

We are casting Lead-antimony alloys into the gravity die casting molds.

cooling rate and eutectic alloy composition also important to avoid porosity/cracks...I think so..