Abstract: The steady operation under extremely low speed of large die forging equipment guarantees the high-performance complex overall die forgings in manufacturing. However, under extremely low speed circumstance, the complex nonlinear friction, hydraulic pressure and material deformation force will cause speed shock even crawling phenomenon. Consequently, the precise control is difficult to obtain at extremely low speed. In view of this question, nonlinear model of complex die forging process is developed at first. Based on the analysis of nonlinear vibration theory, the press speed solving method is proposed, which realizes the approximate solution of the press speed. On this basis, large die forging equipment’s operation rules and reveals the stable operation, speed shock and crawling conditions of large die forging equipment on extremely low speed are analyzed. The simulation results of nonlinear model of complex die forging process verify the correctness of operation rules and the accuracy of speed model. These results provide a theoretical basis for the stable operation precise control of large die forging press under extremely low speed.

Key words: creep, friction, large die forging equipment, low speed, speed shock