Ladle Furnace Liquid Steel Temperature Prediction Model Based on Optimally Pruned Bagging

For accurately forecasting the liquid steel temperature in ladle furnace （LF）, a novel temperature predic tion model based on optimally pruned Bagging combined with modified extreme learning machine （ELM） is pro posed. By analyzing the mechanism of LF thermal system, a thermal model with partial linear structure is obtained. Subsequently, modified ELM, named as partial linear extreme learning machine （PLELM）, is developed to estimate the unknown coefficients and undefined function of the thermal model. Finally, a pruning Bagging method is pro- posed to establish the aggregated prediction model for the sake of overcoming the limitation of individual predictor and further improving the prediction performance. In the pruning procedure, AdaBoost is adopted to modify the ag- gregation order of the original Bagging ensembles, and a novel early stopping rule is designed to terminate the aggre- gation earlier. As a result, an optimal pruned Bagging ensemble is achieved, which is able to retain Bagging＇s ro- bustness against highly influential points, reduce the storage needs as well as speed up the computing time. The pro- posed prediction model is examined by practical data, and comparisons with other methods demonstrate that the new ensemble predictor can improve prediction accuracy, and is usually consisted compactly.

Influence Factors Analysis of Fe-C Alloy Blocking Layer in the Electromagnetic Induction-Controlled Automated Steel Teeming Technology

In the electromagnetic induction-controlled automated steel teeming(EICAST)technology of ladle,the height and location of the blocking layer are critical factors to determine the structure size and installation location of induction coil.And,they are also the key parameters affecting the successful implementation of this new technology.In this paper,the influence of the liquid steel temperature,the holding time and the alloy composition on the height and location of the blocking layer were studied by numerical simulation.The simulation results were verified by 40 t ladle industrial experiments.Moreover,the regulation approach of the blocking layer was determined,and the determination process of coil size and its installation location were also analyzed.The results show that the location of the blocking layer moves down with the increase in the liquid steel temperature and the holding time.The height of the blocking layer decreases with the increase in the liquid steel temperature;however,it increases with the increase in the holding time.The height and location of the blocking layer can be largely adjusted by changing the alloy composition of filling particles in the upper nozzle.When the liquid steel temperature is 1550℃,the holding time is 180 min and the alloy composition is confirmed,the melting layer height is 120 mm,and the blocking layer height is 129 mm,which are beneficial to design and installation of induction coil.These results are very important for the industrial implementation of the EICAST technology.