MOTIONS OF ALLOYING ADDITIONS DURING FURNACE TAPPING IN STEELMAKING PROCESSING OPERATIONS

Numerical computations were carried out to describe the subsurface tra jectories of spherically shaped particles (alloy additions) during sim ulated furnace to ladle tapping operations in steel-making. Complement ing this, experiments in a 0.15 scale water model ladle of a 250 ton t eeming ladle were also carried out so as to simulate the subsurface tr ajectories and total immersion times of various alloy additions as a f unction of (steel) jet orientation, jet entry locations, particle (all oy additions) entry location, particle shape, density, etc. Similarity criteria for model and prototype were deduced on the basis of Froude modeling. The possibilities of additions of various density being entr ained into the bulk liquid and undergoing prolonged subsurface motion were examined for a variety of operating conditions. It was found, how ever, that buoyant spherical particles with apparent densities ranging between 0.4 and 0.9 would, when projected into a recirculating water bath at velocities of 2.7 m/s, record total immersion times of only 0. 1 to 40 seconds. The implications of the water model study, together w ith some idealized sets of computations for an industrial size 250 ton ladle, are analyzed from the viewpoint of industrial alloy addition p ractices. Finally, the results are examined with reference to differen t shaped particles and multiparticle addition procedures, since the la tter are more typical of industrial practice.