Electromagnetic Rapid Casting Composite Magnetic Field Analysis And Aluminum Billet Microstructure And Properties Of Experimental Study

The technology of rapid electromagnetic roll-casting has advantages of both the rapid roll-casting and electromagnetic roll-casting technology, it not only improves the quality of roll-casting products but also promotes the efficiency of production. So this technology will balance the contradiction between the supply and demand of high quality aluminium products in our country, which makes the technology of aluminium machining catch up with the developed countries or even better. With the method of combining theory and experiments, this paper studies the character of electromagnetic force, the distribution of electromagnetic field and the mechanical performance of rapid electromagnetic roll-casting strip. In addition, the paper discusses the rules of the solidification process and solidified structure under different technical and electromagnetic parameters. The main conclusions are as follow:1. The paper analyzes the electromagnetic form when the inductor is electrified with three-phase symmetrical current. By altering the current of each phase or its phase shift, it can reach the aim of adjusting the component of pulsating and travelling magnetic field.2. This paper discusses the character of electromagnetic force in the molten aluminium: the traveling magnetic force cuts the solidifying front to break down the growing columnar crystal;to intensifies structure fluctuation energy fluctuation, the pulsating magnetic force makes molten aluminium vibrating up and down in the solidifying front. The magnitude of electromagnetic force declines with the depth of the molten aluminium increasing, and this trend depends not only the current frequency of inductor, but also on the pole distance of inductor. The result of calculation shows that the electromagnetic field produced by inductor used in the laboratory can meet the need of penetration.3. By improving the test method used before, we test the electromagnetic field again. In addition, the electromagnetic field of the cast-rolling area is analyzed by complex vector method, which provides the distribution of electromagnetic field with theoretical calculation basement.4. By analyzing the metallurgical phase of aluminium strip produced with and without electromagnetic field and in different cast-rolling speed, the results show that the crystal grain of strip is smaller and more dispersing with the technology of rapid electromagnetic roll-casting. By means of stretching test of aluminium strip produced by the technology of rapid electromagnetic roll-casting and its cupping test after cold working, we also find that the mechanical performances and draw ability of strip produced by the new technology are much better than those by the technology of rapid roll-casting and electromagnetic roll-casting.5. In the technology of rapid electromagnetic roll-casting, the commutating period is one of the important electromagnetic parameters, which influences solidification structure seriously. Based on analysis of solidified structure of aluminium strip in different laboratorial conditions, we find that the effect of refinement is the best when the commutating period coefficient is 1, random frequency is ±1, and the frequency of electromagnetic field is 13Hz.