Numerical Simulation Of Initial Solidfication Process In Continuous Casting Mold Of Round Biliels With Electromagnetic Stirring

Mold electromagnetic stirring technique is used to control the casting initial solidification process by applying an alternating electromagnetic field on the outside of the mold, in order to improve solidification organization and the surface quality. Systematic research on electromagnetic field, flow field, temperature field and the initial solidification field helps to further understand the mechanism of the mold electromagnetic stirring, which has important theoretical guiding significance to optimize the continuous casting production process.This paper takes the Φ250mm round billet continuous casting with mold electromagnetic stirrer in a plant as research object. Through the one-way coupling method of sequence, flow field and temperature field distribution of the molten steel in round billet continuous casting was simulated by utilizing ANSYS-CFX. The effects of intensity of electromagnetic stirring, casting speed, nozzle depth of submersion on flow field and temperature field distribution were studied. The results show that flow field and temperature field distribution of molten steel in mold obviously changed under the effect of electromagnetic stirring, The hotspot of liquid steel was improved, the temperature distribution is more uniform. The electromagnetic stirring effect was enhanced with the increase of the intensity of electromagnetic stirring,increasing the intensity of circulating liquid steel, improving the hotspot location.But liquid level fluctuation near the outlet of nozzle will be increasingly intensity with the increase of the stirring intensity,and the slag entrapment phnomenon may happen. Therefore, considering the influence of various factors, the reasonable stirring parameters of the round billet continuous casting mold were 480 A, 3Hz.Based on the CAFE method, The solidification structure of 82 B high carbon steel billet under the continuous casting parameters of a plant was simulated by using the finite element analysis software. The influence of different pouring temperature and maximum nucleation density on the initial solidification organization was studied. The results show that application in continuous casting process with lower pouring temperature contributes to refining the grain and improve the internal quality of billet and the molten steel superheat generally maintains between 15~30℃ in order to guarantee the smooth gating; The grain size will decrease with the increase of maximum nucleation density. Finally, the initial solidfication structures of continuous casting billet were successfully simulated by setting the equivalent parameters of solidification method, based on theoretical analysis.