Simulation Of Preparing Al-Sc Alloy From Sc Ore By Electro Magnetic Tirring

Because the Sc segregation in the Al-Sc master alloy and the lower ratio of Sc can not be solved efficiently in the China, there are not large-scale factory of Al-Sc master alloy. The needed Al-Sc master alloy on industry still mainly depends on imports. And the price of the Al-Sc master alloy is very expensive. Through investigation, we found these problems can possibly be solved by using the continuous casting of electromagnetic crystallizer. So the study of the technology of the using the continuous casting of electromagnetic crystallizer preparing the Al-Sc master alloy seems very important.Since there were many factors which influenced the results of the continuous casting of electromagnetic crystallizer, using the method of the real object test could cost a lot of experimental expense and lengthen the experimental period. After reviewing the mechanism of electromagnetic crystallizer and the development and present situation of the technology of computer simulation of electromagnetic crystallizer, this paper offers the method of the simulation of electromagnetic crystallizer, which could be used emulation of the preparing Al-Sc master alloy. It could order to optimize the operating parameters, save the experimental expense, shorten the experimental period and effectively guide the study of the preparing the Al-Sc master alloy and the manufacture of Al-Sc master alloy in the future. There is the following study in this paper mainly:1) We build the geometric model of preparing the Al-Sc master alloy firstly. We derived the scalar quantity of magnetic quasi-static vector equation in the electromagnetic crystallizer in the cylindrical coordinates by assuming condition for the mathematical modeling of the electromagnetic crystallizer and dimensionless method and reduction of parameters of electromagnetic governing equations. Then we derived the expression of electromagnetic force in the electromagnetic crystallizer in the cylindrical coordinates.2) After analyzing the magnetic field distribution of arbitrary shape coil, we study the distribution of analytical model of traveling magnetic field, rotating magnetic field and electromagnetic force in difference case in the electromagnetic crystallizer. According to the induced electromagnetic field model which has the melt of Al-Sc master alloy, we get the revision of formula of 3-D electromagnetic force.3) After dimensionless method and reduction of parameters of electromagnetic and flow field governing equations, we get the motion equation of the melt of Al-Sc master alloy in the electromagnetic crystallizer. And after considering many complex factors, we derived the expression of FDTD temperature field by conversion and difference of fundamental equation, the expression of simulation of microstructure of solidification process and the expression of 3-D model of evolution of dendrite morphology.4) Representing the description of question of software engineering, the reseau-dividing algorithm that affect the FDTD method, development block diagram and interface of software of the computer simulation of electromagnetic crystallizer in preparing Al-Sc master alloy, we simulate what the loading current and frequency affect magnetic field intensity and magnetic field distribution. We found there was linear relationship between intensity of electromagnetic field and loading current. And intensity of loading current does not change the magnetic field distribution. And intensity of electromagnetic field of the wall surface was larger than the center in the surface position of the electromagnetic crystallizer. And intensity of loading current does affect the decay rate of intensity of electromagnetic field from the edge to center in the circular of the electromagnetic crystallizer. But the frequency affects it largely. The intensity of eectromagnetic field increases as natural exponents with the frequency. The requiring frequency is lower in the electromagnetic crystallizer of preparing Al-Sc master alloy. The optimum of frequency is 2. 5Hz. We discover that Al atom spreads easily than Sc atom by simulating the alternating electromagnetic field effect the melt diffusion of the electromagnetic crystallizer, and periphery atom influence is greater. The activation energy of high diffusion concentration is larger than low diffusion concentration.5) When we simulate what the casting temperature, the cooling rate, the loading current and frequency affect the crystallization temperature of crystallization structure of Al-Sc master alloy in the electromagnetic crystallizer, we discover the difference between the crystallization temperature and the natural temperature of crystallization structure of Al-Sc master alloy in the electromagnetic crystallizer increases as linear relationship, and increase as quadratic polynomial relationship. We point out the crystallization structure is dendrite if the frequency is 1 Hz, and the crystallization structure is coarsening and spheroidization if the frequency is over 3 Hz when we simulate what the loading current and frequency affect the crystallization structure of Al-Sc master alloy in the electromagnetic crystallizer.6) For the verification of the simulation system of the electromagnetic crystallizer of preparing Al-Sc master alloy is reliability, the result of comparison of the magnetic field of the simulatal results and the experimental results that use our experimental device of 3-D magnetic field are basically in accordance. As the melt of Al-Sc master alloy is opaque and high temperature, the verification of the simulation of water could be proved reliability for the simulation of the flow field of the electromagnetic crystallizer of preparing Al-Sc master alloy. The graph of the flow field of computer simulation is similar for the graph of the flow field of the simulation of water. And the result of comparison of the temperature field of the simulated results and the experimental results are basically in accordance. These prove that the rules of temperature field distribution of the continuous casting of electromagnetic crystallizer of preparing Al-Sc master alloy are accurate.7) Processing treatment of Al-Sc master alloy of continuous casting of electromagnetic crystallizer and photography, the result of comparison of the macrostructure and microstructure of the simulated results and the experimental results are basically in accordance. And while the same is true with tests for electromagnetic crystallizer or no electromagnetic crystallizer, the results are the Sc segregation in the Al-Sc master alloy is 43.91% when there is no electromagnetic crystallizer, the Sc segregation in the Al-Sc master alloy is 9.5 percent when there is electromagnetic crystallizer. So the computer simulation of electromagnetic crystallizer in preparing Al-Sc master alloy could help the preparing Al-Sc master alloy.