Дослідження термічної підготовки ковшів

Abstract

The purpose of the work is to develop a computer model of ladle heating with an open torch on a drying and high-temperature heating installation to control the thermal preparation process. The task of managing ladle drying and high-temperature heating installations (USVR) is to implement their operating modes, which ensure obtaining the specified temperature profile of the lining layers of steel castings with minimal fuel consumption. The task of controlling by drying and high-temperature heating unit (SHHS) is to implement their operating modes that provide a given temperature profile of steel pouring ladle lining layers with minimal fuel consumption. Since modern technical means of control do not allow obtaining relevant information about the temperature field of the lining of the walls and bottom of the ladle, it is necessary to create a predictive model of its heating by an open torch at the SHHS. A 68-ton rammed steel-pouring ladle KС-68 was chosen as the object of study. According to the research data, the shape and dimensions of the open torch were evaluated at OCC PrJSC “Evraz- Dnipro Metallurgical Plant”. A digital camera recorded the torch at the burner outlet at a natural gas flow rate of 50 m3/h, which corresponds to the standard mode of drying and warming up the ladle. For modeling purposes, the resulting torch shape was approximated by two truncated cones. Determination of the parameters of convective-radiant heat transfer in the “torch – cover – wall – ladle bottom” system was carried out taking into account the temperature of the torch, the thermophysical properties of the lining materials, as well as the irradiance coefficients and the emissivity of the surfaces. The calculation of the temperature field in the lining of the wall and bottom of the ladle was carried out by the finite element method implemented in the ANSYS package. Based on the simulation, a change in the temperature field of the ladle lining was obtained during its heating at the SHHS with an open torch for 6 hours, which corresponds to the current technology. An analysis of the dynamics of the temperature field of the ladle lining obtained as a result of modeling indicates that when it is heated by an open torch at a drying and high-temperature heating unit, thermal stresses do not occur, which are dangerous from the point of view of cracking in the layers of refractory materials. The maximum temperature gradient in the wall is 10 °С/mm, and at the bottom – 6 °С/mm. It has been established that the working surface of the lining warms up sufficiently to avoid thermal shock when steel is poured into the ladle. The results of the research can be useful for optimizing the process of thermal preparing steel pouring ladles.