Numerical Simulation and Experimental Study of Molten Steel Permanent Magnet Stirring Under Different Rotation Speeds and Magnetic Flux Densities

Compared with electromagnetic stirring, a novel permanent magnet stirring, characterized by high magnetic flux density and low energy consumption, is an effective alternative to produce steel with uniform solidification microstructure. In this study, a mathematical model of PMS is developed based on the multi-physics field analysis software COMSOL and the flow field software FLUENT, and the electromagnetic force and the molten steel flow are calculated under various rotation speeds (50, 150, 300 rpm) and magnetic flux densities (850, 1450, 1800 Gs). The calculated results are consistent with the measured magnetic flux densities. It is found that when the rotation speed enhances from 50 to 300 rpm, the maximum electromagnetic force increases clearly from 1.90 to 11.24 kN/m(3), the maximum tangential velocity varies from 0.09 to 0.47 m/s. Moreover, the maximum electromagnetic force increases from 2.06 to 8.45 kN/m(3) and the maximum tangential velocity varies from 0.11 to 0.38 m/s in a diameter of 50 mm molten steel ingot when the magnetic flux density increases from 850 to 1800 Gs. In addition, the experimental results reveal that the PMS with the rotation speed of 150 rpm and the magnetic flux density of 1450 to 1800 Gs can effectively decrease the size and achieve a uniform distribution of MnS in the solidified 49MnVS3 steel ingot.