| In Continuous Annealing Process Line (C.A.L.), temperature affects not only internal stress and strain of metal, but also variations of microstructures. As users improving requirements of performance of strip steel, to control cooling rate of the strip precisely by thermometry is becoming more and more important. High speed mixed gases of nitrogen and hydrogen jet cooling process is accompanied with high temperature and pressure. Because of the limitation of inspection equipment, it is hard to acquire temperature distribution of the strip accurately. Therefore, accurate simulation of the strip temperature distribution is the prerequisite of strip quality analyzing and controlling. It also has the significance both in theory and reality.At present, researches of cooling process are focusing on technologies, equipments, experiments etc. However, the research about simulations of the strip temperature distribution is scarce. Hence, it is a relatively new field on simulations.The physical and mathematic model of the strip has been established. Temperature field of the strip which is cooled by high speed mixed gases of nitrogen and hydrogen is simulated with ANSYS. Simulated results provide temperature and stress distributions. Cooling speeds are calculated in different conditions. The availability of the model has been validated by contrasting simulated results with experimental ones. First of all, simulations with respect to influences of gases properties (gases composition, jet velocity and gases temperature), characteristics of nozzle (nozzle type and size) and assembly dimensions of nozzles (separation of nozzles, distance between nozzle and the strip) upon temperature distributions and the strip cooling rates are engaged. Secondly, temperature distributions and cooling rates with different strip thicknesses are obtained. Finally, stress distributions and displacements of the strip are simulated in different cooling rates by the method of thermal-structure coupled. |
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