Preparation method of high-fusion-welding-resistance copper-chromium fine-grain composite contact

Abstract

The invention relates to a preparation method of a high-fusion-welding-resistance copper-chromium fine-grain composite contact, and belongs to the technical field of copper-chromium contact manufacturing. The preparation method comprises the steps of powder mixing, 3D printing, heat treatment, wire cutting and surface treatment, wherein a composite layer is CuCr (0.5-2%) alloy powder, a contact layer is CuCr (10-50%) Te (0.2-1%) composite powder. The as-cast composite contact is prepared on the basis of a 3D printing process, and therefore, the interface between the contact layer and the composite layer can be flush, and the density is greatly improved. A Cr phase dissolved in Cu in a solid mode is separated out through shock cooling and heat treatment, the Cr phase is extremely fine, meanwhile, a CuTe phase is separated out, a CuTe brittle phase is formed, and the problem that the fusion welding resistance of an as-cast structure is poor is solved.

Description

technical field [0001] The invention relates to the technical field of manufacturing copper-chromium contacts, in particular to a method for preparing a high-resistant fusion welding copper-chromium fine-grain composite contact. Background technique [0002] Copper-chromium alloy contact material is currently recognized as the best material for vacuum circuit breakers due to its excellent comprehensive performance, and CuCr / Cu series composite contacts have higher electrical conductivity and thermal conductivity than conventional CuCr contacts , and only about 1.5 mm of CuCr layer can meet the requirements, which greatly reduces the thickness, and at the same time, the common AgCu solder can meet the requirements in the welding process with the conductive rod, instead of expensive PdAgCu solder, so the cost can be reduced . [0003] However, at present, CuCr / Cu series composite contacts are mostly prepared by powder metallurgy method. Compared with contacts prepared by conv...

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Problems solved by technology

[0003] However, at present, CuCr / Cu series composite contacts are mostly prepared by powder metallurgy method. Compared with contacts prepared by conventional casting method, although they have good anti-welding performance, they have low density and coarse Cr phase, so their overall performance is poor. , limiting the scope of application of this type of product

Moreover, due to the low strength of the Cu layer, it is easy to deform during use, causing problems such as breaking failure. At the same time, it is difficult to ensure that the joint surface of the CuCr layer and the Cu layer is even, and the preparation is difficult. Finally, the blank prepared by this process still needs to be processed. Subsequent machining with multiple processes such as turning and milling not only has a single and simple style, but also results in a long process and many processes, which greatly increases the manufacturing cost

[0004] Patent CN109355524A discloses a copper-chromium contact material for vacuum circuit breakers and its preparation method, which is composed of the following components by weight percentage: Cr is 20-60%, and the balance is Cu; the raw materials are 30-350 μm respectively Compared with the existing mold pressing and sintering process, the chromium powder and copper powder below 350 μm can be stably produced in large quantities, and large-scale copper-chromium contacts can be produced in batches. The process is simple and the heating process only takes 30-90 minutes , the produced contacts have dense structure, no pores and other defects, and good arc erosion resistance, but the high temperature difference softening temperature is low, and the welding resistance is weak, which cannot meet the requirements of special occasions.

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