A kind of aluminum-chromium alloy and its powder metallurgy forming method

Abstract

The invention discloses an aluminium-chromium alloy and a powder metallurgic forming method thereof. The aluminium-chromium alloy comprises the following components in percent by weight: 70-75 percent of aluminium and 25-30 percent of chromium. The powder metallurgic forming method comprises the following steps of (1) preparing raw materials, auxiliary materials, tools and devices; (2) conducting vacuum induction melting on the alloy; (3) preparing master alloy powder; and (4) conducting powder metallurgic forming. The aluminium-chromium alloy is low in impurity content, fine in crystal particle, homogeneous in component, and high in chromium content, and the powder metallurgic forming method is high in purity, free of pollutants and waste gas, easy to control, stable in quality, and high in finished product ratio.

Description

technical field [0001] The invention relates to the field of aluminum alloy forming, in particular to an aluminum-chromium alloy and a powder metallurgy forming method thereof. Background technique [0002] In the current non-ferrous metal industry standards of the People's Republic of China, the standards for aluminum-chromium master alloys only include aluminum-chromium master alloy AlCr 2 , aluminum-chromium master alloy AlCr 2 Composition standards: Cr content is 2.0-3.0wt%, the balance is Al, impurity Cu content ≤ 0.2wt%, Fe content ≤ 0.5wt%, melting temperature is 900-1000°C, easy to segregate; the national standard stipulates that its production process is : Using aluminum ingots and chromium as raw materials, first melt the aluminum ingots, then add chromium, when the smelting temperature of chromium is reached, manually stir, do low-power analysis, pass the inspection, and cast. The chromium content of the aluminum-chromium master alloy produced by the national st...

AI Technical Summary

Problems solved by technology

Among the relevant patents that have been applied in China, the patent "Aluminum-chromium master alloy and its preparation method" (application number: 200910028727.X, publication date: 2009-01-09) discloses an aluminum-chromium master alloy and its preparation method, but in its production process, because there is no vacuum environment, degassing and impurity removal are insufficient; because there is no restriction on the crucible material for melting, it is possible to use a conventional cast iron crucible, which will make it difficult to control the content of impurity iron. Non-vacuum smelting is used, and electromagnetic stirring equipment and powdering process are not used, and the original grains are not refined enough, which leads to the small number of nucleation that the final aluminum-chromium alloy can provide when used as a grain refiner. The distribution is uneven and the grown grain size is large. At the same time, because the method of powder metallurgy is not used, the ratio of chromium supersaturation cannot be adopted (if it is supersaturated, it is easy to segregate, which will lead to uneven composition of the intermediate alloy ingot. Application Inaccurate weighing), so the chromium content is low, that is, the efficiency of the product is low; on the other hand, compared with the conventional method, the method adopted in this invention will still produce waste gas and waste residue that are difficult to handle, and because there is no high-efficiency equipment, The whole process is not easy to control, and the quality of the final aluminum-chromium alloy is not stable

The patent "An Aluminum-Chromium Master Alloy AlCr20 and Its Preparation Method" (Application No.: 201510191542.6, Publication Date: 2015-07-29) discloses a formula that uses a supersaturated chromium ratio for production, but due to no powder process, its segregation is difficult to guarantee, and because the high-temperature electric furnace is directly used for smelting, the degree of oxidation of the molten metal must be high, and the temperature rises to 1865°C-1890°C, the aluminum has already been burned or gasified, and it is no longer possible to continue smelting

Images