Process metallurgy Operational experience with a mathematical model for temperature prediction in secondary steelmaking Prashanta Deb, Aniruddha MUkhopadhyay, Ahindra Ghosh, Biswajit Basu, Sanjeev Paul, Gopal Mishra, Jayanta Kumar Saha, Rameshwar Sharma and Soumitra Sarkar A previous study has reported the development of flow and thermal model for gas purged ladle and validation of the same by comparison with literature. This paper presents further development of an integrated process model from tapping at LD to teeming at tundish location. The model was tuned and validated with plant data. The model shows a match of temperature within (± SOC) between prediction and measurement for most of heat data. The model was then used to carry out sensitivity test for the various important process parameters in order to find out quantitative influence of these on steel temperatures. The findings have been reported here. Betriebserfahrungen mit einem mathematischen Modell zur Vorausberechnung der Temperatur in der Sekundarmetallurgie. Eine vorangehende Untersuchung beschreibt die Entwicklung eines Modells zur Strornunq und Thermik in gasgespOlten Pfannen sowie die OberprOfung der Ergebnisse mit Literaturwerten. Diese Arbeit zeigt die Weiterentwicklung eines integrierten ProzeBmodelis fOr den ge- samten Bereich vom Abstich eines LD-Konverters bis zum Tundish. Die Feineinstellung und OberprOfung des Modells geschieht mit Anlagendaten. Die Genauigkeit der mit dem Modell ermittelten Temperaturdaten liegt fOr die meisten Werte bei ± SoC (Modellvorausbestimmung gegenOber gemessenen Warmedaten). Das Modell wurde anschlieBend zu Empfindlichkeitstests herangezo- gen, in denen die wichtigsten ProzeBparameter hinsichtlich ihres quantitativen Einflusses auf auf die Stahlschmelzentemperatur unter- sucht wurden. Auch diese Ergebnisse werden prasentiert, Steelmaking process involves operations like ladle preparation, tapping of liquid steel from LD, transfer of ladle, on-line purging (OLP), processing at ladle furnace (LF), final transfer to caster tundish and teeming into the continuous casting mould. The secondary steelmaking route at LD-2 shop, Tata Steel, Jamshedpur, India, from LD tapping to teeming into mould, as chosen in the present study is shown in figure 1. Recently, a parallel processing route involving RH degassing has been commissioned. However, it is not a part of the present investigations. The previous part of this study [I] has described the mathematical modelling of fluid flow and heat transfer and its validation using data from literature. The present paper includes application of the same for prediction of tem- peratures at various stages of secondary steelmaking from LD tapping to teeming into tundish. For this purpose, the following additional studies were carried out. Flow and thermal modelling [I] were extended to ladle furnace, ladle holding and teeming from ladle by incorpo- rating their additional features in the model. Plant data were collected from LD-2 shop of Tata Steel, Jamshedpur and the model was tuned and tested for per- formance. need careful modelling of the ladle in an integrated fash- ion, are: heat transfer modelling of the refractory layer, - heat effects of additions, - heat transfer modelling of top surface. The ladle of Tata Steel LD2 is of 130 t having a porous plug at the bottom and it is located eccentrically. In mod- elling the porous plug, nozzle based correlation for the plume characteristics was used to model the plume in the ladle based on the study of Mukhopadhyay et al. [I] who showed that then prediction based on nozzle-based corre- lation agrees well with the measured flow field in a ladle with porous plug. Since the aim of the present simulation is to predict the temperature field in the ladle, porous plug locations have been assumed to be centric so that two- dimensional simulation could be carried out. Due to the highly turbulent nature of the flow field, heat transfer is largely governed by the turbulent diffusion rather than the effect of three-dimensional swirl due to the eccentric noz- zle. As a result, assumption of centric plug would not have any effect on the thermal field so long as the effect of turbulent flow on thermal diffusion is accurately modelled, as was carried out in the present study. Figure 1. Secondary steelmaking process Mathematical modelling A detailed mathematical modelling for prediction of flow and thermal field in the ladle furnace has been re- ported by Mukhopadhyay et al. [1]. Apart from the flow and thermal transport issues, other major issues which Prashanta Deb; Aniruddha Mukhopadhyay; Biswajit Basu, Tata Rese- arch Development & Design Centre, Hadapsar Industrial Estate, Pune; Ahindra Ghosh, Department of Materials & Metallurgical Engineering, Indian Institute of Technology, Kanpur; Sanjeev Paul; Gopal Mishra; Jayanta Kumar Saha; Rameshwar Sharma; Soumitra Sarkar, Tata Steel, Jamshedpur, India. LD OLP LF CCUnit 200 steel research 72 (2001) No. 5+6