Dynamic control of lubrication characteristics in high speed tandem cold rolling

Friction in continuous process varies irregularly depending on the material conditions, lubrication conditions and industrial environment. While control of friction in industrial processes is being improved empirically by trial and error, friction control within the optimum range for each process is essential. The recently proposed hybrid lubrication system is helpful to achieve higher rolling speeds and more stable rolling in order to improve the productivity of tandem cold rolling mills. In this paper, an intelligent lubrication control system for preventing chatter was proposed. In a basic study, the vibration stability of the rolling mill was investigated by using a self-excited vibration model. For stable high speed cold rolling, it is important to optimize the balance of the friction coefficients in a multi-stand rolling mill. Based on this idea, a new actuator for controlling the friction coefficient balance was proposed. Lubrication characteristic control by the flow quantity feedback in hybrid lubrication system was evaluated by a dynamic rolling simulation based on MATLAB/Simulink and demonstration experiments in actual rolling mill. Feedback control of the plate-out oil film from a hybrid lubrication system could be achieved as an actuator for balancing the friction coefficients between the final stand and preceding stand. The results of this research suggest that the hybrid lubrication system with the proposed actuator is possible to prevent chatter efficiently in high speed cold rolling region.