| The Aluminum continuous roll-casting process is a relatively new technology of press processes in recent decades, which has a series of excellent characters comparing with traditional hot-rolling technology with the cast ingot, for example, fewer investment, short production period, low cost, less energy-consuming and so on. In the Aluminum continuous roll-casting process, the molten aluminum has the character of directional solidification, that is to say, the directionality of crystal growth is strong and the deep draw performance is far less than that of obtained with traditional hot-rollig technology which restricts its use badly. The Aluminum electromagnetic roll-casting is a new technology with high efficiency and less energy-consuming by introducing the electromagnetic technology into the Aluminum continuous roll-casting process. For different Aluminum alloy or different molten aluminum having different frequency response, this paper focus on the mechanism of electrolytic molten Aluminum electromagnetic roll-casting. By analyzing the basic structure and the power supply system of electromagnetic roll-casting, confirms that the electromagnetic inductor adopts two-phase low frequency alternating current power supply, the iron core loop to be focus-winding and the power supply system of the Aluminum electromagnetic roll-casting to be designed alter-alter frequency conversion device without logic loop. Based on the mass experiments and industry trials, analyzes and discusses the solidification mechanism of electrolytic molten Aluminum under electromagnetic field environment, sets up the dynamical model of the roll-casting section molten aluminum and puts forward the mechanical rub domino offect to explain the effects of the Aluminum electromagnetic roll-casting on the microcosmic structure and the mechanical performances of the electromagnetic roll-casting Aluminum strips. According to the mechanical relax peculiarity, confirms the optimal electromagnetic field frequency to be 10 to 20 Hz and the optimal direction conversion cycle of excitation current to be 3-5 times of that of the excitation current by theoretically calculation and analysis. Studying the mechanism of the Aluminum electromagneticroll-casting without analyzing the electromagnetic field is impossible, so this paper also focuson analyzing the electromagnetic field. On the one hand, In the light of vector calculusprinciple and electromagnetics theory, explains the generation of traveling wave and pulsewave in detail and illustraters the work principle of the Aluminum electromagnetic roll-casting,which by producing an alternating complex electromagnetic field required to electrically stiror to electrically disturbance the molten aluminum in the stuff-supply mouth and roll-castingsection so as to fine the grains and improve the integrated performance of the continuousroll-casting strips. On the other hand, drawing lessons from the linear induction meteranalytical method, divides the complicated three-dimension electromagnetic field into atwo-dimension and a one-dimension electromagnetic field and sets up correspondinganalytical models. In the one-dimension analytical model, deduces the mathematic formulas ofthe gas gap magnetic flux density and the push force of the electromagnetic inductor. Byanalyzing and calculating the Y-Z two dimensional electromagnetic field of the Aluminumelectromagnetic roll-casting with finite element method, the result shows that the roller dragsthe magnetic lines of flux forwards so as to lead the magnetic lines of flux to the formersolidification-crystallization border of the roll-casting section, which is favourable forgrain-fining and destroying the mechanism of molten aluminum directional solidification.However, the roller aggravates the side electromagnetic loop as a result of being made offerroelectric substance. We can optimize the gas gap electromagnetic field so as to maximizeths magnetic flux density of the former solidification-crystallization border of t... |
PDF Full Text Request