| AINiCo permanent magnet has better temperature stability, time stability and corrosion resistance property than other permanent magnets and is widely applied to instrument and meter's permanent magnetic devices which are used in armaments and spacecrafts, such as torpedo, guided missile, airplane and satellite and so on. Besides, it is the principal material manufacturing high-end medical apparatus and instruments and electronic alloys. The aerospace technology's, rapid development requires higher and higher performance and machining precision of key electromagnetic components and parts which determine controllers'precision and performance. For instance, there is an domestic aerospace research institute which is producing the magnet rings used in some part of the plane at present, it demands the material's formation is well-closed, the single plane's edge broken area of the magnet ring is not more than 0.3mm2 and the surface roughness must reach nanometer level, but because of the little know about the material's microstructure and deficient study on the material property, we can not established effective material evaluate method and standard. Meantime, the existing process leads to severe edge broken and high defective index which can not satisfy the requirements for the lack of theory guidance, it has become a burning bottleneck problem in producing the magnet ring of the institute.In view of above problems, this paper brings forward and checks solve schemes based on the in-depth analyzing the material property and machining process flow. The main work of this paper is summarized as follows:(1) studied the metallographic phase analysis method of cast LNGT80J magnetic steel, defined the preparing process of metallographic phase samples including grinding time, grinding parameter and corrosive and so on, besides, observed and analyzed the microstructure of cast LNGT80J magnetic steel with the Olympus MX40 metallographic phase microscope.(2) Programmed relevant programs to analyze the metallographic images, calculated the y (orαγ) phrase content, grain's cross section area and porosity which is harmful to the material property of cast LNGT80J magnetic steel.(3) Analyzed the micro hardness and its uniformity of cast LNGT80J magnetic steel. Measured the average Vickers Hardness HV200=759.17 from the experiment and the result indicates the material belongs to hard materials. We found the hardness distribution is not even by analyzing the distribution of Vickers Hardness along the samples'length direction which in the 17 tested points the different value between the maximum and minimum Vickers hardness is 47.(4) In view of the present process flow causing the serious edge broken of magnet ring, analyzed the reason of edge broken and improved the present process flow including adjust the turn of process flow and ameliorate the key process. The result indicated that adopting the new process flow to produce the cast LNGT80J magnet ring can reduce edge broken greatly.(5) Researched the key process in the cast LNGT80J magnet ring's new process flow-solid abrasive lapping, analyzed the relationship between the Material Removal Rates (MRR), machined surface roughness and lapping pressure, lapping speed, abrasive grain size. Got the best lapping process parameters when the surface roughness and MRR is evaluation index separately from optimizing the process parameters, and they can be used in primary lapping and precision lapping cast LNGT80J magnet ring.(6) Build the surface roughness and MMR lapping process parameter models of solid abrasive lapping cast LNGT80J magnetic steel, and verified the correctness of the parameter models with the experiments. |
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