1994 Volume 80 Issue 10 Pages 748-753
An attempt to clarify the clogging mechanism of immersion nozzle from the standpoint of wettability has carried out by preparing the following substrates: substrates of Al2O3 and ZrO2-CaO, which are main components of nozzlematerials, substrates of Al2O3 and Al2O3-MgO, main components of inclusions, and substrate of Al2O3-CaO, reaction product by contact of inclusion with ZrO2-CaO nozzle. Contact angles between these substrates containing CaO orMgO lower than 20mass% and liquid irons were measured at 1873K.
In the cases using irons containing the same level of oxygen as molten steel for continuous casting, the following relations are obtained by comparing the values of contact angle obtained for each substrate;
Contact angle: Al2O3, Al2O3-MgO>ZrO2-CaO≥Al2O3-CaO.
These results indicate qualitatively that the use of ZrO2-CaO refractory instead of Al2$#O213 refractory as immersion nozzle may lead to a retardation of adhesion of Al2O3 inclusions to the refractory, though decrease in force of adhesion dueto the observed changes in wettability is only about 30%.