Abstract: In order to investigate the clogging mechanism of submerged entry nozzle during casting Tibearing IF steel by BOF→RH→CSP process.The composition of clogs on submerged entry nozzle was studied by scanning election microscopy (SEM), energy dispersive spectroscopy (EDS).Finally, the clogging mechanisms of submerged entry nozzle were elucidated by combining with the characteristics of inclusion in tundish.The investigated results indicated that the clogging easily occurs because that wetting angle was decreased due to containing titanium in molten steel.The clogs close to the inner surface of submerged entry nozzle, which was composite oxide of Al2O3-CaO-SiO2-MgO but mainly consists of Al2O3, was resulted from reaction between refractory material of SEN and acidsoluble aluminum in molten steel.However, the clogs close to molten steel comes from the deposition of inclusions containing Al2O3 or spinel of MgO·Al2O3 and iron particles.The rate of clogging was increased because that the molten steel easily adhered to net sintered inclusions.The studied results will provide theoretical guidance for rising the continuous casting heats of tundish and improving the quality of products by means of optimizing the process parameters.

Key words: Ti-bearing IF steel, clogging of SEN, deposition of inclusion