The Casting Of Secondary Cooling Water Heat Transfer And Artificial Intelligence Optimization Model And Control

The first part of this thesis is dealing with the mathematical modeling of a two-dimensional, non-steady-state solidification heat-transfer process, usefl.xl for the automatic control for 4th slab continuous caster in Anyang Iron & Steel Group Co. Ltd.. Based on the consideration of the restriction for the surface temperature of the production target~ a model-solving emulator has been programmed in VC++ language. It can be used to simulate the heat-transfer and cooling process in the secondary cooling zone, and to calculate the target water quantity and controlling parameters for every cooling loop. This model has been used in production practice.Based on the requirements of five kinds of steel products, the slab with two cross-sections, and the concrete conditions of practical casting process, the water quantities of all loops in secondary zone and the relationships between the casting speed and water quantities of all loops are calculated. The influence of casting speed and the degree of overheating on the casting process has been analyzed, in order to obtain the useful information for the consideration of the scheme for optimal automatic control of the water cooling process.Based on the requirements of different production conditions, the preset and preset-feedforward controlling systems for the automatic control of every cooling-water loops have been given. By consideration of the mutual relationships between different cooling loops, the controlling systems with slab surface temperature feedback and that with water quantity compensating formula have been obtained. It is more useful for the stabilization of slab surface temperature and more beneficial for slab quality.The Second part of this thesis is dealing with quality defects of slab produced after the realization of the automatic control based on the above-mentioned two-dimensional cooling-solidification model. The slab surface temperature data were obtained by the measurement of HWSG-2B computer-controlled infrared radiation colorimetric thermometer. Based on the data of surface temperature of slab, the optimal model (involve three kinds of steel grades) of secondary cooling of slab continuous casting has been first worked out in domestic and abroad by pattern recognition methods. This model has been applied into practice over half a year and satisfactory results have been achieved. With tire meantime, an expert system of secondary cooling of slab continuous casting has been built by artificial neural network, it is convenient to be used for the upgrade of the casting products of steel-making mills.