Novel Design of Submerged-Entry Nozzle for Steel Continuous Casting

摘要

Homogenization of molten steel flow in the mould is quite important for assuring quality of steel to be produced in the continuous casting process. Since suppression of the adhesion of Al_2O_3 based inclusion to the ejection port and inner bore of the submerged entry nozzle (SEN) as a final outlet of the molten steel to the mould is considered as a key factor of stabilizing the molten steel flow in the port ejection, development of stepwise type and mogul type geometry of the SEN inner bore, application of SiO_2 or B_2O_3 as a substitution of Al_2O_3-C based SEN materials in conjunction with investigation on the improvement effect of the anti-adhesive in the case of CaF_2 or CaO addition to the ZrO_2 based materials, and multilayer type nozzle structure have been tried in previous research works so far. In the meantime, from another points of view, application research of spinel-C based materials to improve anti-erosion property of nozzle itself in spite of opposite of anti-adhesive property have been carried out, and effect of Ar gas blowing on the adhesion, mechanism of adhesion, device of evaluation method of adhesion and case study of fluid analysis in conjunction with computer simulation using fluid dynamics of molten steel flow have been reported. However, despite of tremendous efforts described above, stabilization of port ejection flow in the SEN has not yet been achieved.