Numerical simulation and application of argon blowing from tundish cover for bloom continuous casting

Abstract

During the continuous casting process, the remaining oxygen in the tundish can be significantly decreased by argon blowing from the tundish cover(ABTC). As a result, the effect of protective casting can be obviously improved, which helps decrease the reoxidation of molten steel in tundish. In the present work, numerical models for ABTC of a six-strand continuous casting machine were established and verified by the measured oxygen mass fraction in tundish during ABTC. The results indicate that the best conditions of ABTC are installing the argon pipes on either side of the tundish cover holes, sealing the baking holes, and keeping stopper rod holes open. The argon flow rate should be ?120m3/h during the period of empty tundish and ?60m3/h during the period of normal casting. Industrial trials of ABTC based on the calculation results were carried out. The results indicated that the increased nitrogen in steel(?w[N]) from the end of RH to tundish decreased by 21.5% from 8.78?10-6 to 6.89?10-6, and the amount of inclusions except for MnS in bloom (scanned size: 8mm?8mm) decreased by 21.3% from 13.43 to 10.57, and the average size of inclusions decreased by 19.0% from 9.27?m to 7.51?m.