| Strip laminar cooling process of hot rolled the coiling temperature, and the strip coiling temperature control precision directly influence the mechanical properties of steel and its microstructure and properties,is a decisive factor in ensuring the quality and the shape of the strip. Therefore, it is of great significance to analyze and study the laminar cooling process control system.In this paper, the laminar cooling system of hot rolling mill, steel as the background, how to improve the control precision of coiling temperature and optimization of laminar cooling process of in-depth study of the system.The cooling mechanism of the strip are analyzed, the basic way of the strip(thermal radiation, heat conduction, heat conduction and convection),mathematical model of laminar cooling process of hot rolling mill are analyzed in detail. Water cooling model and air cooling model is a major component of this model, and the heat flux model is an important parameter affecting the cooling effect, therefore, the strip coiling temperature control model is established to improve the control precision of coiling temperature has important significance.For the laminar cooling control strategy in China are analyzed, and a detailed analysis of the various functions of the control strategy of the laminar cooling process of the factory. In the specific implementation process, we can see that the laminar cooling process control is a pre-set calculate and feed-forward correction calculation, feedback control system as control, and the analysis and evaluation of the application of the system in the actual production, the control strategy of some of the deficiencies and the direction of improvement analysis.The main reason for volume control precision and lower temperature in the feed forward and feedback calculation are put in the same level and only use the experience formula to calculate the precision of coiling temperature control model; whether the preset feed forward and feedback are assumed or calculated temperature is uniform in the thickness direction of. We will calculate the feed forward and feedback are placed in the two stage, in the length direction of the sample, the feed forward control for each sample,sample period as far as possible the feedback control, adaptive temperature deviation at the same time according to the length of the strip thickness calculation; we adopt layered in temperature calculation, considering the heat conduction layer the calculation of surface temperature of hot strip rolling at any point on the output of each layer and temperature, provided the conditions for the accurate prediction of the performance of the strip, the strip is more precise control of the temperature.Focus on the description of the hot rolled strip plant of temperature stratification calculation sample period of feed forward, feedback and adaptive control and variable temperature control method. |
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