Energetické fórum

Poznámka: 

Surface temperatures of cast slabs at small radius segments in front of as well as at the un-bending point belong to parameters that affect the surface quality of continuously cast slabs. Older ma-chines for continuous casting were designed with regard to the performance (to amount of cast slabs) rather than to the quality. Therefore, the adaptation of secondary cooling is required in order to accom-plish the desired surface temperatures. The modification consists in the dynamic control of secondary cooling, surface temperatures monitoring by means of the numerical model of temperature field as well as in a prospective replacement of cooling nozzles. In order to optimize and control the secondary cooling, characteristics of nozzles and especially the influences of water flow rate, air pressure, casting speed and surface temperatures to the heat transfer coefficient under nozzles have to be known. Moreover, the heat transfer coefficient can be also influenced by the age of nozzles. The paper deals with relationships of described influences and their impacts to the temperature field of cast slabs. The results are presented for the 1530 x 250 mm slabs that are cast in Evraz Vítkovice Steel where the main author’s dynamic 3D solidification model is used to control the production interface and runs in off-line version. Its results can be used as a preparation tool for the real casting process.