Research And Application Of Advanced Cooling Technology For Medium Plate Mill

In the production of medium plate, TMCP (Thermo Mechanical Control Process) is an important technology to improve the performance and the quality of products, the cooling control can not only reduce rolling load, but also reduce the added alloying elements, save energy, reduce consumption and the cost of production. Study shows that the reasonable equipment design and mathematical model, which can improve cooling effect and raise control precision. Be based on the 12th Five-Years national science support plan "Development and Application of New Generation TMCP Hot-Rolled Strip Steel Equipment and Process Technology", and the national key basic research development program (973 Plan) "Structure Control Theory and Technology Research of High Performance Steel "as the background, we deeply research the flux characteristics during the cooling process, the change regulation of the internal temperature,and the main influencing factors of cooling rate, combining with UFC (Ultra-Fast Cooling) system of 3000mm thick plate rolling production line in one steel mill. Main research contents and results are as follows:(1) Be based on actual UFC equipment, we simulate the flow of cooling water on the surface of the steel plate in the cooling process, research the change regulation of impact pressure and velocity of fluid, and analyze the characteristics of different equipment design.(2) Be based on the actual production, we build process control system and deeply research the model of heat exchange coefficient in order to improve precision. According to the actual data, we worked out the relation between coefficient of heat transfer and flux density and temperature by the simulation. To some degree, the calculation precision of final cooling temperature is improved.(3) Be based on new development, we make the cooling process parameters and study the temperature field in the thickness direction under these parameters, such as different flux density, different speed and different thickness of steel plate in cooling process. Draw conclusions:the greater water flux density, the stronger heat transfer ability; the slower speed, the greater temperature drop; the greater thickness, the weaker cooling capacity of heart and the effect on the surface is not obvious.(4) Be based on the actual production, we study the change of internal temperature under different cooling strategies, and analyze the effect of cooling capacity, cooling speed and the influence on the shape by different header status. All of these can give a certain reference value to make cooling process in the industrial production.(5) The research has been used in the actual production process control. Taking Q345 reduction as the example, the results show that the application of UFC technology can greatly reduce alloying elements and obtain the good economic benefit on the basis of meeting the performance and guaranteeing the flatness.