Multidimensional electromagnetic modulating device for electromagnetic stirring of slab crystallizer

Abstract

The invention discloses a multidimensional electromagnetic modulating device for electromagnetic stirring of a slab crystallizer. The multidimensional electromagnetic modulating device comprises a stirrer system (1), a crystallizer system (2), metal liquid (3) and a speed measuring system; the stirrer system comprises a PLC control unit and two single-side stirrers distributed on wide faces of two sides of the crystallizer, the single-side stirrers comprise multilayer stirrer units, a magnetic shielding sheet is arranged between the stirrer units arranged on every two layers, the stirrer unit arranged on each layer comprises multiple coils and magnet yokes, the PLC control unit is connected with coil taps, the current amplitude and phase positions of the coils are changed, and transverse magnetic field modulation can be achieved; the stirrers on each layer are independently connected to the PLC control unit, so that the longitudinal magnetic field modulation is achieved; the speed measuring system comprises a speed measuring probe and an intelligent processing unit, the speed measuring probe is arranged on narrow faces of the crystallizer, and the flow velocity of the metal fluid in the crystallizer can be measured in the direction of the wide faces; a measured speed signal is sent to the intelligent processing unit by the speed measuring probe, and the signal is processed by the intelligent processing unit and then output to the PLC control unit.

Description

technical field [0001] The invention relates to an electromagnetic stirring device of a metal slab crystallizer, in particular to a multi-dimensional electromagnetic modulation device for electromagnetic stirring of a slab crystallizer. Background technique [0002] In the production of metal slabs, in order to improve the surface and internal quality of the slab, electromagnetic stirring is usually applied to the liquid metal in the mold. The basic principle of electromagnetic stirring is to generate an alternating magnetic field by inducing an alternating current inside the stirrer. This alternating magnetic field will induce a current in the liquid metal, and a Lorentz force will be generated between the induced current and the alternating magnetic field. Under the action of Lorentz force, liquid metal flows along the direction of the combined external force. On the one hand, the flow field under the action of electromagnetic stirring scours the solid-liquid interface...

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Problems solved by technology

[0003] Chinese patent CN96121903.3 proposes to divide the stirrer into four independent control parts, which can generate different magnetic field distributions by applying different currents. This method has a certain degree of adjustability, but the stirrer can only achieve horizontal adjustment without considering the plate Billet difference in longitudinal direction

[0004] The electromagnetic stirring device proposed in Chinese patent CN87104014 produces a spiral magnetic field, which is beneficial to the floating of air bubbles and inclusions, and can be used for electromagnetic stirring of billets and round billets. The stirring form and the effect of the convective field have certain limitations in slab continuous casting limitation

Chinese patent CN86101657, Chinese patent CN200910226351.3, U.S. patent US4582110, and U.S. patent US5279351A propose stirring technologies that are all rotating magnetic field generators, used for electromagnetic stirring of billets and round billets, and are not suitable for stirring in slab continuous casting process

[0006] Chinese patent CN200910302486.3 proposes an inductor that can realize five stirring modes of single rotation, electromagnetic deceleration, electromagnetic acceleration, two-zone rotation and four-zone rotation. These adjustment modes are essentially two-dimensional magnetic field adjustments, which can only Changes the magnetic field distribution in the cross-section, but cannot be adjusted in the longitudinal direction

In addition, the corner of the slab is a crack-prone area, and none of the five modes can flexibly and effectively adjust the stirring magnetic field at the corner of the slab

[0007] Chinese patent CN200780041938.6 proposes a new electromagnetic stirring method, using two sets of coils, one set generates a rotating magnetic field in the cross section, and the other generates a moving magnetic field in the longitudinal direction. This method can realize three-dimensional electromagnetic stirring, but the main It is suitable for electromagnetic stirring of round billets, but electromagnetic stirring of slabs has not yet been realized

[0008] The electromagnetic stirring method and device mentioned in the above patents are limited to two-dimensional electromagnetic stirring or billet and round billet stirring, and cannot realize fine-tuning of the local stirring magnetic field, and have limited ability to adjust the inner corner of the crystallizer or the local dead zone of the molten metal. It is very easy to become a high-incidence area of ​​inclusions or pores; secondly, although the electromagnetic stirring technology of the slab crystallizer has achieved certain application effects, there are still problems of unstable slab quality, and defects such as inclusions and pores often appear. Electromagnetic stirring The effect needs to be further improved; for slab continuous casting, slabs with different compositions and specifications will be produced on the same continuous casting machine, and there are certain differences in the process parameters of continuous casting, so the electromagnetic stirring process of the mold must be carried out accordingly. Corresponding adjustments, for the flow field in the crystallizer, it is necessary to take measures to adjust the overall or local magnetic field in the horizontal and vertical directions, but there is currently no method and technology for multi-dimensional magnetic field modulation, which is not conducive to the improvement of slab quality

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