Testing the Veining Elimination using Pressure Changes and one Type of Additive in a Cold-box-amine Core Mixture

This article presents a analysis of the impact of varying amounts of a specific additive in the core mixture and adjustments in shooting pressure on the elimination of surface defects in castings, particularly veinings. These defects, often located in inaccessible areas of the casting, cannot be effectively removed through conventional methods like punching, making the optimization of the core mixture composition crucial. Additives are frequently incorporated into the core mixture, as they have become an essential component in its production. For the core mixture to be effective, it is not only essential to identify the appropriate type of additive but also to precisely determine the optimal quantity of the additive and accurately set other critical production parameters, such as shooting pressure.This study investigates the influence of additive concentration and shooting pressure on the surface quality of cast iron castings, employing the cold box method for core production. The findings reveal that higher shooting pressure contributes positively to the reduction of veining defects. However, an increased additive content in the core mixture does not necessarily ensure vein-free castings. The additive also plays a role in reducing the gas content within the core, and increased core hardness is associated with a decrease in the occurrence of veining defects. The casting with the highest surface quality and the fewest veinings was produced using cores made from a mixture with 1% additive content, subjected to a shooting pressure of 4 bars.