Permanent modifier capable of improving electrical conductivity of hypo eutectic Al-Si alloy as well as preparation method and using method of permanent modifier

Abstract

The invention belongs to the metallurgical field and particularly relates to a permanent modifier capable of improving electrical conductivity of a hypo eutectic Al-Si alloy as well as a preparation method and a using method of the permanent modifier. The permanent modifier comprises the following components in percentage by weight: 1-4% of Sr, 5-20% of lanthanum-cerium-rich mixed rear earth and the balance of Al, wherein a weight ratio of the Sr to the lanthanum-cerium-rich mixed rear earth is 1 to (5-10). The preparation method for the permanent modifier comprises the following steps: firstly, preparing materials and smelting the prepared materials; and then, carrying out alloying and carrying out thermal extrusion by virtue of billets prepared by extruding and casting to prepare a modifier wire, thus obtaining the permanent modifier product capable of improving electrical conductivity of the hypo eutectic Al-Si alloy, wherein effective modifying time is at least 5 hours. The permanent modifier disclosed by the invention is convenient to use, stable in effect, long in effective modifying time, free of a modifying incubation period, and has effective modifying time of at least 5 hours according to detection. And moreover, the electrical conductivity of the alloy treated by virtue of the modifier wire is obviously improved.

Description

technical field [0001] The invention belongs to the field of metallurgy, and in particular relates to a long-acting modifier for improving the electrical conductivity of a hypoeutectic Al-Si alloy and a preparation and use method. Background technique [0002] Aluminum-silicon alloy is one of the most widely used cast aluminum alloys, widely used in high-voltage power transmission equipment, such as high-voltage switches, high-voltage tanks, etc. [0003] The addition of silicon in the aluminum-silicon alloy makes the alloy not only maintain the advantages of metal aluminum, but also improve the fluidity and wear resistance of the alloy, reduce the tendency of thermal cracking and shrinkage of the alloy, and ensure the good casting performance of the alloy; but The eutectic silicon of the unmodified hypoeutectic aluminum-silicon alloy is in the form of thick plates or strips, which severely splits the aluminum matrix and reduces the strength and plasticity of the alloy. [...

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Problems solved by technology

[0006] At present, the commonly used modifiers for hypoeutectic Al-Si alloys mainly include Na modification, Sr modification, Sb modification, Te modification and RE modification, among which Na modification and Sr modification are the most common in industrial production, and the modification effect is the most ideal, but Na modification The effective metamorphic time is only about 40 minutes. During the metamorphic process, equipment will be corroded and harmful gases will be generated. Therefore, its application in industrial production is limited; Sr metamorphism has an incubation period of about 30 min, and it is easy to produce inclusions of strontium-containing compounds, and the metamorphic process has a tendency to get gas. Causes a large number of pores in the casting, thereby reducing the mechanical properties of the alloy

[0007] However, it is found through experiments that the improvement of the electrical conductivity of the hypoeutectic aluminum-silicon alloy after the above-mentioned modification agent is modified is not ideal. Taking the ZL101 alloy as an example, the electrical conductivity of the ZL101 alloy after the above-mentioned modification agent is modified is shown in Table 2. For this reason, It is necessary to study a long-acting modifier for improving the electrical conductivity of hypoeutectic Al-Si alloys

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