Abstract: In production practice, some continuous casters suffer from severe resonance during their starting although the vibration frequency of mold is much lower than the natural frequency of the vibration system. The resonance can cause shake of liquid steel level and, more seriously, even industrial accident such as breakout. In view of this phenomenon, the torsional vibration model of non-sinusoidal oscillation system driven by oval gears is built up. And the dynamics equations are deduced. Low-frequency resonance is discussed. Factors which influence the resonance frequency are considered. A solid foundation for solving the running smooth problem of the mold and for better application of the oscillation device is laid.

Key words: Continuous casting, Low-frequency resonance, Mold, Non-sinusoidal oscillation, Oval gears