Characteristic Analysis of Mold Level Fluctuation in Continuous Casting Based on Wavelet Transform

Liquid level fluctuation in the mold has a significant impact on slab quality. As a time‐frequency analysis tool, wavelet transform (WT) has been successfully applied to the analysis of such fluctuation. In this study, the WT is used to decompose the liquid level fluctuation of the mold based on the data of the stable state for a complete casting sequence, and to construct the energy distribution sequence of the liquid level fluctuation. The time‐frequency characteristics of abnormal liquid level fluctuations and their causes are also systematically analyzed in combination with process parameters such as tundish weight and casting speed. The results show that the rate of weight change of the tundish is the key factor inducing the abnormal fluctuation of the liquid level, and the fluctuation of the liquid level is significantly aggravated when the rate of weight decrease exceeds 0.14 t s −1 or the rate of increase exceeds 0.1 t s −1 . When the casting speed is lower than 1.68 m min −1 , it can reduce the frequency of abnormal liquid level fluctuations occurring in the mold when the tundish weight drops during the ladle exchange procedure.