The effect of non-sinusoidal oscillation amplitude on liquid friction force in mold with casting speed 2. 0 m/min has been analyzed by a mathematical model of liquid friction combined a non-sinusoidal oscillation waveform with optimum mode virtue to get amplitude selection principle and determination method. The calculated results for 1 270 mm x 210 mm cast bloom of SPHC steel (≤0. 08C) showed that the maximum liquid friction force could be restricted by applied small amplitude

increased flux consumption

decreased negative strip time

and defined optimum amplitude ± 4 mm at cast speed 2. 0 m/min； and amplitude should be increased suitably with increasing cast speed in order to improve oscillation effect at real time.