THEORETICAL-STUDY ON THE SEPARATION OF IN CLUSION PARTICLES BY PINCH FORCE FROM LIQUID STEEL FLOWING IN A CIRCULAR PIPE

The pinch force which is one of the most general electromagnetic force s in the metallurgical field can be generated by impressing an electri cal current in a liquid metal. In this force field, electrically nonco nductive particles suspended in a liquid metal will receive a force in the opposite direction to the pinch force, and be squeezed out from t he liquid metal. In the present study, this principle was applied to t he separation of nonmetallic inclusion particles from liquid steel. Th e separation efficiency eta of inclusion particles from a circular pip e flow of liquid steel was thought to be a function of the following n ondimensional parameters: V-R(=V-Pt/W-m), C-I(=mu(e)I(rms)(2)/rho nu(2 )), D-R(=d(P)/2r(1)), Re=(r(1)W(m)/nu), Z=(Z/r(1)), and r(1)/delta. Th e plug-flow model and the particle-trajectory model were used for calc ulating eta. The results obtained by both models showed that eta was a function of V-R, (CIDR2/Re)Z and r(1)/delta. The particle-trajectory model showed a smaller value of eta than the plug-flow model. The valu e of eta calculated by the former model increased with increasing (CID R2/Re)Z and decreased with increasing V-R. Although eta did not change with r(1)/delta when r(1)/delta<1, it decreased gradually with increa sing r(1)/delta in the region of r(1)/delta>l. The values of eta for a channel induction heater installed in a continuous casting tundish we re estimated to discuss the practicability of the present inclusion se parator. It was found that eta was greater than 95% for inclusion part icles with the diameter greater than 60 mu m.