Speed control strategy and rule of the FGC stand in a tandem cold rolling mill

According to flying gauge change (FGC) characteristics of a tandem cold rolling mill (TCM), a speed control strategy of the FGC stand with the strip tension set-point before FGC as a control target was put forward. Based on the developed analytic mathematic models of strip elastic deformation under tension between stands, the speed control rule of the FGC stand was derived under the condition of small gauge change by single step, and the speed of the other stands having finished the FGC process was calculated based on the constant mass flow principle. When the dimensions or material properties of two kinds of strips varied great, the method using wedge was also took to carry out FGC, and the control rules of rolling speed and gauge set-point for every thickness of the wedge were derived and calculated by using the developed strategy. The deviations of strip thickness produced by FGC were limited in the stands before and behind the FGC point, and the interference of the FGC stand to the others was eliminated, then the process control for FGC could be implemented easier.