Cleaning Molten Steel with the Centrifugal Flow Tundish

A new process was devised for promoting inclusion separation from the steel in a tundish. The process utilizes electromagnetic force to rotate molten steel in a cylindrical chamber. This process is refered to as the Centrifugal Flow Tundish (CF Tundish). In this work, oxygen content and the number of inclusions in the tundish are examined in an industrial plant to estimate the performance of deoxidation and inclusion separation. A new mathematical model was developed and the deoxidation rate constant in the rotation chamber of the CF tundish is estimated at as much as 0.7 min-1. This large deoxidation rate is considered to be due to the large turbulence energy of the CF tundish. Large inclusions over 10μm in diameter reduce with the CF tundish during the ladle exchange as well as during the steady state casting. 2-phase fluid dynamic simulation using the VOF method revealed that this large inclusion separation in the CF tundish can be explained by the restraint of the short circuit flow. Thus, this process has been commercially used to produce clean Al-killed stainless steel with high quality.