Analysis on Electromagnetic Field of Continuous Casting Mold Including a New Integral Method for Calculating Electromagnetic Torque

Abstract

Based on the Maxwell's equations, a finite element model is established to study the characteristics of electromagnetic field in the mold of billet and bloom continuous casting with electromagnetic stirring (M-EMS). A novel integral method for calculating electromagnetic torque is proposed to evaluate the stirring intensity of stirrer. In order to verify the accuracy of the model, a well-designed electromagnetic torque detecting device is fabricated. The predicted value of electromagnetic torque and magnetic flux density are consistent with the measured data. The optimum frequency is determined by the maximal electromagnetic torque of the strand. The effect of stirring current intensity and different stirrer positions along the length of mold on the electromagnetic field has been studied numerically. The results show that the optimum frequency is smaller when the copper tube of the mold is thicker and the section size is bigger. Besides, the electromagnetic torque of the strand is a quadratic function of the running current intensity. Moreover, the installation position of stirrer strongly affects the prediction of electromagnetic field distribution, further influencing the optimum frequency and the electromagnetic torque of strand.

Behavior of Mold Electromagnetic Stirring for Round Bloom Castings and Its Eccentric Stirring Problem

“…Each measured value is roughly consistent with the calculated value, which can further indicate the high accuracy of the M-EMS model. The measured value is gradually smaller than the calculated value as the current intensity is increased because the magnetic saturation characteristics of the silicon steel core are not considered in the model, and the measured value is gradually larger than the calculated value as the current frequency is increased because the Joule heating effect of the mold copper tube is not considered in the model, which is consistent with the research of Li [28]. In addition, the opposite variation pattern of magnetic flux density and torque values in the range of 1 Hz to 2 Hz indicates that the magnetic flux density as an intermediate parameter between current and electromagnetic force cannot accurately reflect the strength of the stirrer driving the molten steel flow, and the electromagnetic force cannot be measured in the presence of the steel during the actual production process, as the electromagnetic torque driving the molten steel flow can directly characterize the real electromagnetic stirring performance.…”

“…The electromagnetic force cannot be measured due to the high temperature of molten steel in actual CC production. An [27] and Li [28] both designed electromagnetic torque measurement devices to obtain the induced electromagnetic torque in the strand by experimental measurement and model calculation. In addition, when M-EMS was installed at the position not too far beyond the mold, an optimal stirring frequency corresponding to the maximum stirring intensity of M-EMS was proven to exist.…”

Effect of M-EMS current intensity on the subsurface segregation and internal solidification structure for bloom casting of 42CrMo steel

“…According to Li and Zhang [16], the electromagnetic field (EMF) for the low-frequency operation of M-EMS can be given as follows:…”

A Numerical and Experimental Study on the Solidification Structure of Fe–Cr–Ni Steel Slab Casting by Roller Electromagnetic Stirring

“…The effect of the solid and liquid phases of steel with little different electrical conductivity was ignored in the high-temperature zone on the electromagnetic force. The development of coupled equations for the electromagnetic field, flow field, heat transfer, and solidification behavior are relatively mature, as described in detail by Li et al [14] and Wang et al [15]. The principles of the linear stirrer are shown in Figure 2 [16].…”