Abstract：Time-frequency analysis is an effective method to explore the characteristics of fluctuation signals and reveal the internal mechanism of fluctuation phenomena. The time-frequency analysis method was applied to study the level fluctuation in argon blowing continuous casting mold, and it was used to process the level fluctuation data obtained by a water model experiment. The effects of various operating parameters such as argon blowing rate, casting speed, nozzle immersion depth and mold width on the level fluctuation were studied to explore the internal mechanism of level fluctuation. Results show that the frequencies with high amplitude are concentrated in 0-2.5 Hz, and the fundamental frequency with the largest amplitude is near 0.1 Hz. In addition, there are high peaks noticed at 1.5 Hz and 2.5 Hz. Based on the time domain analysis, level fluctuation intensity will be aggravated by increase of argon blowing rate and casting speed or decrease of nozzle immersion depth and mold width. Based on the frequency domain analysis, the casting speed, nozzle immersion depth and mold width strongly correlate with the fundamental frequency of level fluctuations, indicating that they are highly related to the main vibration sources.
LI Y, DENG A, ZHANG L, et al. A new type of magnetic field arrangement to suppress meniscus fluctuation in slab casting: Numerical simulation and experiment[J]. Journal of Materials Processing Technology, 2021, 298: 117278.
YU S, LONG M, ZHANG M, et al. Effect of mold corner structures on the fluid flow, heat transfer and inclusion motion in slab continuous casting molds[J]. Journal of Manufacturing Processes, 2021, 68: 1784.
[9]
WU Y, LIU Z, WANG F, et al. Experimental investigation of trajectories, velocities and size distributions of bubbles in a continuous-casting mold[J]. Powder Technology, 2021, 387: 325.
[10]
WU Y, LIU Z, LI B, et al. Numerical simulation of multi-size bubbly flow in a continuous casting mold using population balance model[J]. Powder Technology, 2022, 396: 224.
YANG J, CHEN D, LONG M, et al. Transient flow and mold flux behavior during ultra-high speed continuous casting of billet[J]. Journal of Materials Research and Technology, 2020, 9(3): 3984.
Popescu T D. Time-frequency analysis[J]. Control Engineering Practice, 1997, 5(2): 292.
[19]
REN L, ZHANG L, WANG Q. Measurements of surface velocity and level fluctuation in an actual continuous wide slab casting mold[J]. Metallurgical Research and Technology, 2018, 115(1): 102.
[20]
DU M, JIN N, GAO Z, et al. Analysis of total energy and time-frequency entropy of gas-liquid two-phase flow pattern[J]. Chemical Engineering Science, 2012, 82: 144.
[21]
JIANG Z, SU Z, XU C, et al. Abnormal mold level fluctuation during slab casting of peritectic steels[J]. Journal of Iron and Steel Research International, 2020, 27(2): 160.
[22]
Ebrahimi A, Kleijn C R, Richardson I M. A simulation-based approach to characterise melt-pool oscillations during gas tungsten arc welding[J]. International Journal of Heat and Mass Transfer, 2021, 164: 120535.
[23]
Teshima T, Kubota J, Suzuki M, et al. Influence of casting conditions on molten steel flow in continuous casting mold at high speed casting of slabs[J]. Tetsu to Hagane, 1993, 79(5): 576.
2022, Vol. 32 
