The Problem of Cavities in Open Mold Conveyor Remelt Ingots

Open mold conveyor casting machines for 8–25kg ingot produce millions of tonnes of remelt ingot every year. However, these ingots suffer from cavity formation. These cavities represent a safety risk during remelting of the ingots due to the possibility of water molten metal explosions if the cavities contain water. The formation mechanisms of these cavities and the effect of alloy, machine design and operational parameters are reviewed. Alternative means of controlling cavities are examined and assessed. The need for a new approach to the problem is highlighted.