A Computational Study of Feeding Rules and Yield Improvement Techniques

The results of a computational study of feeding and the promotion of feeding by yield improvement techniques is presented. The computer simulations were performed using a commercial solidification software package examining the simple plate-like geometries addressed in the SFSA feeding rules. Solidification criteria from the computer model were used to develop simulation determined feeding distances which are then compared with feeding distances determined by the SFSA guidelines. In many cases these comparisons indicate that the present feeding guidelines are overly conservative. The advantages of increasing casting yield through increased feeding distance by using yield improvement methods is also investigated. Improved feeding distances and casting yields resulting from using insulating riser sleeves and block chills (termed passive methods), and active heating and cooling are presented and compared. The benefits of increasing the casting yield through the vertical stacking of castings, and the semi-continuous casting of vertically coupled and stacked castings is also presented.