热轧带钢层流冷却温度优化控制策略研究

在热轧带钢生产过程中,卷取温度是影响成品带钢性能的重要参数之一,其精度的高低对带钢质量至关重要.为保证产品具有良好的性能,采用层流冷却装置对热轧后的板带进行冷却控制,喷水系统的设定是层流冷却过程控制的关键.在冷却过程中带钢的温度不能在线连续检测,其过程具有强非线性和时变性,而且在冷却过程中存在相变,因此难以建立精确的数学模型去描述这一冷却过程.随着带钢厚度,精轧出口温度和轧制速度的变化,单独的前馈/反馈控制很难满足高精度的温度控制需要.在本文的研究中,一系列层流冷却控制策略被采用,包括前馈/反馈控制,自适应算法,以及控制带钢整体温度的均匀性策略.实践应用表明这些控制策略得到很好的检验,能有效地提高卷取温度的控制精度和均匀性.

Research on Optimizing Control Strategy of Temperature for Laminar Cooling during Hot Strip Mills

Coiling temperature,an important factor determining the mechanical properties of hot rolled strips,has a great influence on strip quality.In order to assure better properties,laminar cooling system is implemented in the cooling of hot rolled strip,and the setting of spraying system is a key point of cooling system.The temperature of strip can not be measured continuously along Run-out Table.Mathematical model is insufficient for describing laminar cooling process due to non-linear,time-variation,and phase transition.The conventional control system with forward/feedback does not have a good adaptive capability when the boundary conditions vary,including strip thickness,finish rolling temperature,and rolling speed.Cooling strategies,elements tracking,homogeneity of temperature control and dynamic correction are employed in this study.Rolling tests with various grades of steel covering a wide range of thickness show that the developed model can improve the accuracy of coiling temperature control to obtain an uniform mechanical properties.Good correlation has been found between the predicted temperatures and the actual coiling ones.