Sergey Makarov, Reinhold Ludwig¹, and Diran Apelian

Metal Processing Institute, Department of Mechanical Engineering,
¹Electrical and Computer Engineering Department,
Worcester Polytechnic Institute, Worcester, MA 01609-2280.

The role of detecting non-metallic and weakly-conducting inclusions in hot melts is of major importance during the manufacturing process in that every aspect of quality is affected by the presence of secondary phases. However, the weak link is how one quantitatively determines the level of inclusions. In this paper, we present a theoretical model and preliminary experimental results for a magnetic force-based detection system to monitor small inclusions of micron-size. The idea is to force these non-conducting inclusions to a detection location (the free melt surface) by electromagnetic Archimedes forces. Further, an optical imaging system can then be applied to detect them visually. The theoretical modeling efforts include the force model, the surface concentration model, and the escape model of the submerged inclusions.

The developed technique potentially has the best resolution performance when compared to other on-line methods. The application area includes hot melts of metals and other high-conductive non-transparent fluids. Low-temperature experimentation with liquid gallium has been conducted to prove this nondestructive measurement concept.