Research On The Control Strategy Of Molten Pool Level In Twin-Roll Thin Strip Vibrating Casting And Rolling

The twin-roll thin-strip vibration casting technology is a new technology proposed on the basis of the traditional thin-strip continuous casting process to improve the microstructure defects of the thin strip.It is related to the quality of thin strip products and whether the whole process can be carried out normally.In view of the different emphasis on the process requirements of different stages in the casting and rolling process,this paper takes theΦ500×350 vibration casting and rolling mill as the object and industrial pure aluminum as the material,and divides the molten pool level control into the unstable casting and rolling stage and the stable rolling stage.Do research.The casting and rolling experiments were carried out,and it was found that in the early stage of casting and rolling,the phenomenon of liquid leakage and rolling would easily occur due to the unreasonable casting and rolling speed.It is found that the mechanical properties of the defect are significantly decreased,which lays a certain foundation for the staged research on liquid level control.A mathematical model of the liquid level control of the molten pool in twin-roll thin-strip casting and rolling was established,and the valve-controlled hydraulic cylinder was used as the stopper rod lifting device and its mathematical model was established;combined with the actual use of the stopper rod and nozzle size,the flow characteristic model of the stopper rod was established,and the stopper rod was analyzed.Effective stroke,combined with experimental verification and measured plug flow correction coefficient C_SR;build molten pool liquid level model according to the law of mass conservation.Finally,the modeling of the molten pool level control system is completed by combining the models.For the non-stable casting and rolling stage,since the liquid level is formed at the beginning of the casting,the heat exchange inside the molten pool has not reached a dynamic equilibrium state,and liquid leakage or jamming is prone to occur.Therefore,the research focus of this stage is to minimize liquid leakage,and Also avoid rolling cards.To this end,a two-dimensional thermal-fluid coupled finite element model of the molten pool area of twin-roll thin strip casting was established,and the influence of the casting speed on the temperature field and flow field of the molten pool with time was explored,and the roll speed was determined according to the influence law.The climbing curve and the matching relationship between the roller speed and the change of the stopper rod during the roller speed climbing process were studied to maintain the stability of the liquid level.It is verified by the established mathematical model of molten pool level.It provides some theoretical guidance for the liquid level control in the unsteady casting and rolling stage of the twin-roll thin strip.For the stable casting and rolling stage,the heat transfer balance in the molten pool does not consider the influence of the temperature field.The research focuses on making the liquid level control have good dynamic response and anti-interference ability.For this purpose,a genetic algorithm is designed to optimize the fuzzy control,and the simulation is carried out.The results show that it is superior in control effect.