FEM Numerical Simulation Of The Low-frequency Electromagnetic Sealing In Hot Galvanizing Process

The requirements of hot dip galvanized sheet are greatly increased with the rapid development of automobile industry, household appliances industry and computer industry, and so on. However, in the traditional hot dip galvanizing process, the surface defects of steel strip and the pollution of zinc liquid resulted from the sinking roll, the self-corrosion of the sinking roll have hindered greatly the improvement of quality and output for the galvanized sheet. Eliminating the sinking roll and realizing the hot dip galvanizing process without the sinking roll is a hot topic. Electromagnetic sealing technology provides a new method to eliminate the sinking roll.At the present, Electromagnetic sealing technology in the hot dip galvanizing process at home and abroad is still studied in the lab. Therefore, in this paper, based on the electromagnetic theory, numerical simulation research for the electromagnetic sealing technology was carried in order to obtain the factors influencing electromagnetic sealing and changing law and provide the theoretical basis for experimental study.Combining numerical simulation with experimental study can get more detailed and accurate results and shorten greatly the study cycle. Therefore, based on the low frequency travel wave magnetic theory, the formula applying for the electromagnetic sealing technology awe derived, and mathematic model was established to simulate the electromagnetic sealing process by using simplified Maxwell electromagnetic equations and ANSYS software in this paper. The experimental device was designed and manufactured according to the mathematic model and the accuracy of the calculating model and methods were verified by contrast of the experimental and calculating results.The numerical simulation of electromagnetic sealing process was realized by direct coupled mode of electric field and magnetic field in the ANSYS software. By studying the variation of the magnetic field around the zinc liquid, the induced current inside the zinc liquid and the electromagnetic force in the zinc liquid, the influence of the current and frequency, the gap and the relative position between the sealing tube and magnetic pole, and the width and the material of the sealing tube on the electromagnetic force was obtained. The results show that in this paper the optimal electromagnetic force is obtained when the current is 80A and the frequency is 50Hz, and the gap between the sealing tube and magnetic pole is not more than 7.5mm and the sealing tube is placed in the middle of the electromagnetic pole, the electromagnetic force in the zinc liquid is large and stable. In addition, the material of the sealing tube decided the distribution of transverse current in the zinc liquid, then it contributes to reach the better results of electromagnetic sealing that the suitable material of the sealing tube is selected and the width of the tube is not less then 300mm when manufacturing the electromagnetic sealing equipment.