热轧带钢轧后冷却控制系统优化

为提高热轧带钢超快冷出口温度和卷取温度控制精度,针对超快冷生产调试过程中出现的问题,对轧后冷却控制系统进行了优化.针对超快冷出口纵向温度偏差较大的问题,提出超快冷换热系数多点自学习方法;采用有限差分方法,分析带钢超快速冷却后的返红现象,并在此基础上提出一种超快冷出口返红补偿方法;提出了对进入冷却区的带钢样本段进行温度再计算的方法,来消除速度波动对轧后冷却温度控制精度的影响.现场应用结果表明,优化后超快冷出口温度和卷取温度控制精度均明显提高.

Optimization of Cooling Control System on the Run-out Table of Hot Strip Mill

In order to guarantee high control accuracy of ultra-fast cooling zone delivery temperature and coiling temperature， the run-out table cooling control system was optimized according to the major problems emerging from the tuning process of ultra-fast cooling. Aiming at the longitudinal temperature fluctuations after ultra-fast cooling， a new self-learning method for the heat transfer coefficients of ultra-fast cooling was proposed. The strip surface re-reddening phenomenon after ultra-fast cooling process was simulated with the finite difference method， based on which a compensation for strip surface re-reddening was added to run-out table cooling control system. In order to eliminate the influence of strip conveying velocity fluctuations on temperature， the strip conveying velocity diagram and temperature were recalculated for all strip segments which had entered the cooling sections， as soon as a new strip segment came to the measuring point of finish mills delivery temperature (FDT). With the methods mentioned above， the new run-out table cooling control system are optimized and field application showed that the strip temperature control accuracy are improved obviously.