Establishment And Study Of Plate Temperature Field Model During Plate Rolling Process

Plate production is the process of thermal processing, heating, rolling, cooling, cutting and other manufacturing processes are all in a range of specific temperature, as production progresses, the plate temperature is changing constantly, the inner structure and stress state of the plate are also constantly evolving. The precise forecasting and control of plate temperature field is not only the foundation to achieve high-precision control of plate size, more important, is the guarantee to achieve microstructure evolution and overall performance prediction and control of steel.The plate temperature field model in rolling process is researched deeply in this paper in the background of a domestic plate production line automatic control system modification project, the effect of various factors in rolling process impact on plate temperature field are considered sufficiently, heat transfer coefficient model in various stages in rolling process are established and solving with absolute convergence of the implicit difference method. Data in rolling log is selected in off-line temperature field calculation, by comparing with calculate results and measured temperature, minify the difference between calculated temperature and measured data. The feasibility of online application of the temperature field model is verified. The major researches are as follows:(1). Base on heat transfer mechanism, the plate temperature field model in rolling process is established. The three heat transfer ways in rolling process are analysis, one-dimensional heat conduction equation is proposed for the characteristic of plate, the plate is discrete in space and time and construct in difference scheme, the formula of surface and inner notes calculated by implicit method are derived.(2). Determination and optimization of heat transfer coefficient in different rolling stage. The heat transfer coefficient are calculated respectively in air cooling stage, descaling stage and rolling stage, the previous assumption that the plate temperature distribution is symmetry to the center line of thickness is broken, the effect of convection with air and conduction with roller table are considered in the calculation of plate surface heat transfer coefficient in air cooling stage, and the heat transfer coefficient is adjusted according to different scale thickness; the plate temperature difference between head and tail is calculated caused by the back flow of descaling water in descaling stage; the temperature variation caused by conduction and deformation are considered at the same time in rolling stage.(3). The development of plate temperature field real-time calculation system in rolling process. The system is programmed base on MFC dialog in VC++6.0and can work as a independent process, the system has a good interactive interface, the instant surface, inner and the average temperature of the plate can be displayed.(4). Offline program simulation. The plate temperature field are calculated off-line in all stages of rolling process with the data in rolling log and the calculate system in this paper, by comparing with calculation results and measured data, the model accuracy is higher than the original model, which instruct the feasibility of online applications of the temperature field model.