The Terminal Prediction Parameter Model Of VD And Its Application

VD (Vacuum Degassing) is the important equipment for reducing the content of hydrogen, nitrogen and nonmetal inclusion in the molten steel. Molten steel is processed in the vacuum, so the steeling-making terminal parameter is very difficult or can hardly be measured continuously. For most VD, the smelting terminal parameter is acquired by the experience of the operator, which influences the operation of smelting process directly. So, the prediction model of the molten steel temperature and the content of the nitrogen are studied in this thesis.To resolve the problem of less precision for the existing temperature prediction model under small samples condition, a VD molten steel temperature prediction model based on SVM is established in this thesis. In this thesis the in-out parameter is fixed by studying the production technics. In order to obtain the SVM (Support Vector Machine) parameter quickly and accurately, the GA (Genetic Algorithm) is adopted to realize the choice of model parameter. The simulation shows that the model is effective under small samples condition.To resolve the problem of less precision for the nitrogen mechanism model, a nitrogen prediction model based on SVM is established in this thesis. In order to improve the precision of the model, the mechanism model is studied carefully, and in this thesis the mechanism knowledge is put into the SVM model; and then the VD nitrogen terminal prediction model is established. The SVM model predicts the inputting parameter demanded by mechanism model, and then takes the parameter into the simplized mechanic model; thereby the prediction of nitrogen is acquired. The simulation shows that the hybrid model gets the better predicting precision.According to the practical production process, the automatic system of VD for the manufacture is designed in this thesis, which includes the design of computer-controlling hardware system, the software design of basic automatic system and process automatic system. The real-time monitoring of VD production is realized by basic automatic system, and the terminal parameter of VD smelting process is achieved by the process automatic system.