Research On The Control Method Of Molten Steel Level Control And Rolling Force Control For Twin-Roll Casting

Twin-roll casting is the molten steel continuous casting to a pair of oppositely rotating water-cooled rollers, it is a near technology for molten steel being solidified into a thin strip directly. Due to omission of the hot rolling process, production costs of thin strip significantly reduced. Twin-roll strip casting as a new technology is being subject to worldwide steel industry attention in the present. The core control elements of twin-roll casting process are molten steel level control and rolling force control. The key of producing high quality thin strip is the control precision. This article deeply researches on the molten pool liquid level and rolling force control methods of twin-roll casting from the theoretical modeling and simulation experiment respectively.Firstly, the paper introduces the twin-roll casting process, analyses the influence of process parameters (such as pouring temperature, casting speed, height of liquid level and the roll gap distances) on rolling force during the twin-roll casting process, and the overall control scheme is designed for molten pool liquid level and rolling force in the process.Secondly, the control model is established between a DC motor and rolling force, and a fuzzy PID controller is designed by the combination of PID control method and fuzzy control method, theoretically implement the purpose of both ideal transient performance and steady-state performance. The control system of rolling force is designed and simulation researches are carried out by using Simulink Toolbox in MATLAB software. The simulation studies showed that overshoot of molten steel liquid level is about2.7%, settling time is0.45s, steady-state error is0.6%by the control system, and this system has good immunity.Finally, the models of electro-hydraulic servo valve, hydraulic cylinder, stopper flow and molten steel liquid level are set up. The PID controller of stopper, the fuzzy adaptive PID controller of molten pool liquid level and the molten steel liquid level cascade control system are designed. The simulation studies showed that overshoot of molten steel liquid level is about0, settling time is3.7s, steady-state error is1.35%by the control system, and this system has good immunity.