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Influence of submerged entry nozzle on intermixed zone in round blooms with a diameter of 525 mm

Michalek K., Gryc K., Tkadlečková M., Morávka J., Huczala T., Bocek D., Horáková D.

Archives of Metallurgy and Materials

2013

Vol. 58, iss. 1

187-191

This work compares the experimental results of nickel concentration measurements in the intermixed zone of the continuously cast round blooms with a diameter of 525 mm using two types of submerged entry nozzles (SEN) - a straight-through nozzle and one with 5-ports. Based on determination of the system and optical interface in the blooms a detailed study of concentration profiles on the bloom surface in a small radius area, on the right side and then also on a cross-section of the blooms, was carried out. The results were further analysed using approximation models, and were to be used to verify the proposed model for predicting intermixed zones for a continuous casting machine, developed based on the results of physical and numerical modelling.

Praca przedstawia porównanie wyników pomiarów doświadczalnych stężenia niklu we wlewkach okrągłych o średnicy 525 mm odlewanych metodą COS z strefa przejściową, przy użyciu dwóch typów wylewów zanurzanych typu SEN - wylewu osiowego oraz promieniowego 5-strumieniowego. Pomiary wykonano na powierzchni wlewków oraz na ich przekroju poprzecznym przy użyciu metod optycznych. Analizę uzyskanych wyników pomiarów przeprowadzono wykorzystując modele aproksymujace. Uzyskane w ten sposób rezultaty wykorzystano do modernizacji opracowanego wcześniej w oparciu o rezultaty badan o charakterze modelowania fizycznego i numerycznego modelu do prognozowania wielkości strefy przejściowej dla badanego urządzenia do ciągłego odlewania stali.

Possibilities of S-EMS utilization for the improvement of central segregation in continuously cast billets in conditions of TŽ

Cibulka J, Bocek D., Huczala T., Cupek R.

Journal of Achievements in Materials and Manufacturing Engineering

2012

Vol. 55, nr 2

638--643

Purpose: The aim of the paper is to investigate practical possibilities of the strand stirrer (S-EMS) for the improvement of inner quality and central segregation in high carbon billets. An optimal S-EMS setting was proposed for the billet caster producing billets 150x150 mm. Design/methodology/approach: Impact of different S-EMS settings on central segregation and inner quality of as-cast billets was investigated. A set of longitudinal and transverse samples were analysed including evaluation of baumann prints and central segregation by means of LECO method. Samples of wires for segregation survey in rolled products were picked up as well. Findings: It was observed that application of the strand stirrer (S-EMS) is capable to suppress central segregation. However, its impact is visible just to a certain stirring level. Subsequent increasing of stirring intensity does not cause further improvement of segregation in the analyzed central part. On the contrary, stronger white band can be seen in the solidification line. Moreover, concentration gradient between the central part and surrounding ring of negative central segregation is lowered. These two effects can play a significant role in the evaluation of segregation level in rolled wires. Research limitations/implications: Analysis of central segregation in a lower size than used 6 mm. Practical implications: Optimal S-EMS setting seems to be 300 A/14 Hz. Originality/value: Impact of S-EMS setting on changes in central segregation of as-cast billets, relationship between central segregation level in wires and cast structure.