APPLICATION OF PINCH FORCE TO THE SEPARATION OF INCLUSION PARTICLES FROM LIQUID STEEL

The pinch force which is one of the most common electromagnetic forces in the metallurgical field can be generated by imposing an electrical current on a liquid metal. In this force field, electrically noncondu ctive particles suspended in a liquid metal experience a force in the opposite direction to the pinch force, and are squeezed out from the l iquid metal. In this study, the above principle was applied to the sep aration of nonmetallic inclusion particles from liquid steel. Firstly, the separation efficiency, eta, of nonmetallic inclusion particles fr om the liquid steel flowing in a circular pipe was calculated by the t rajectory method under laminar flow conditions. The value of eta was f ound to be a function of V(R), (C(I)D(R)2/Re)Z and r1/delta, where r1 is the radius of the pipe, delta is the skin depth and V(R), C(I), D(R ), Re and Z are nondimensional parameters. The estimated value of eta in a continuous casting tundish equipped with a channel-induction furn ace was greater than 95% for particles with a diameter over 60 mum. Se condly, the value of eta for a square pipe was computed by the concent ration method. In this case, the value of eta was found to be a functi on of V(R) and (C(I)D(R)2/Re)Z at x1/delta=0, where x1 is the half wid th of the square pipe. However, with increasing x1/delta, secondary fl ows appeared in a cross section of the pipe because of the skin effect . These flows were found to increase the value of eta by transporting the particles in the inner region toward the wall.