Temperature Prediction And Controlling Model In LF Refining Process

In ladle furnace refining process, temperature and component control are the two masterstroke from the beginning to the end. In order to stabilize production and improve the quality of the billet, the temperature of the molten steel is required more strictly by continue casting. Electric supply is the main measure of increasing the molten steel temperature, a reasonable electricity supply system not only can insure the temperature of the molten steel, but also can satisfy the need of production rhythm. The purpose of this search are calculating and forecasting the accurate temperature of the molten steel at different refining process. On the basis of this, in allusion to material conditions and craftwork demands, it can establish the rational temperature controlling system—power supply time.A new mathematical model used for forecasting molten steel temperature during LF refining process is established on the basis of heat transfer principle with theoretical analysis. The heat transfer in ladle wall (including side and bottom) is described with non-steady differential difference equations under one-dimension cylindrical coordinates and rectangular coordinates. Collecting thirty stove data coming from practical refining process, the temperature of molten steel is predicted by program authorized in Visual Basic. It is eighty-eight percent that the error between practical temperature and predicted temperature is no more than±5℃.The temperature of the molten steel is mainly related to electricity,absorbing heat of ladle line,exhaling heat of melting pool surface, convection result from wiping off dust,blowing argon alloy and residue. The former two influence the temperature of molten steel importantly, account for mainly quotient, the temperature diversification of molten steel resulted from blowing argon can be ignored.This model consist of tow parts:temperature prediction and power supply time. In temperature prediction part, the temperature of molten steel is predicted by smelt craftwork parameter at the end of refining, the temperature transformation is also predicted during refining process. On the basis of temperature prediction, the reasonable supply time is calculated according to required refining time,temperature at the begin of refining and at the end of refining, according to this, reasonable power supply time can be put forward. This model is weaved into engineering software, it can reduce the times of power cut and measuring temperature,shorten refining cycle,economize electricity,reduce consumption of thermocouple, it is high practicable.