Investigation on Al_2O_3-C based nozzle clogging during billet continuous casting of mid-carbon steel

The cause to the clogging of the Submerged Entry Nozzle(SEN) during billet continuous casting of mid-carbon steel as well as the preventative measures have been investigated.The chemical compositions of the clogging materials are analyzed and inclusions in steel samples out of the ladle,tundish and billet observed by the optical microscope and SEM and the total oxygen content across the whole section of the billet quantitatively measured and the nozzle clogging condition numerically simulated.Results show that the clogging materials around the nozzle mainly originate from alumina inclusions and Al2O3-MgO spinels in steel as well as the produce out of the hot metal corrosion on the inner lining of the ladle and tundish and in the meanwhile solutions to the nozzle clogging of the mid carbon steel put forward accordingly.