Studies of new coating materials to prevent clogging of submerged entry nozzle (SEN) during continuous casting of Al killed low carbon steels

摘要

The possibility to reduce clogging in the submerged entry nozzle when casting Al killed low carbon steel has been evaluated. The coating materials have been tested in laboratory trials and pilot plant trials. Totally, two mixes of the coating material have been tested, containing 4.8 and 9.1% CaTiO3 mixed with yttria stabilised zirconia powder. The chemical composition was analysed using a field emission gun-scanning electron microscopy equipped with energy dispersive X-ray spectrometry. The major result showed that alumina reacted with CaTiO3 in the temperature interval from 1550 to 1600 degrees C. In addition, the clogging ratio showed a decreased clogging tendency for coated nozzles compared to standard nozzles. In addition, the results showed that an approximately three times higher steelmass could be teemed through the coated nozzles before clogging occurred compared to trials with uncoated standard nozzles. Overall, it is concluded that plasma sprayed CaTiO3 coatings can reduce the clogging tendency during the continuous casting process.