Aluminum-silicon-magnesium casting alloy mechanical property improving method

Abstract

The invention discloses an aluminum-silicon-magnesium casting alloy mechanical property improving method. Light rare earth is adopted and cooperates with heavy rare earth to process alloy melt, and the iron content is 0.09-0.20 wt% of the alloy melt mass. According to the improving method, based on the difference, in the aspect of physicochemical property, between light rare earth elements and heavy rare earth elements as well as the influence on the alloy crystallization process, the method of utilizing the light rare earth and the heavy rare earth to be combined and modified to control the microstructure and mechanical property of alloy is provided, the light rare earth and the heavy rare earth give play to advantage separately, namely, the light rare earth is focused on enriching on thealpha-Al and Si crystal solidification front and being adsorbed on the surface of crystal, and achieves the effects of refining and modifying; and the heavy rare earth is focused on adsorbing or conducting solid solution on iron-rich Al-Fe and Al-Fe-Si group harmful compound, influencing the microstructure of the compound, impeding growth of crystal, and promoting the compound to be decomposed into short rod-like shape or granular shape at the high temperature; and the light rare earth and the heavy rare earth achieve mutual complementarity in the aspect of controlling the microstructure of the alloy, and substantially, the quite good modifying effect is achieved.

Description

technical field [0001] The invention relates to the technical field of alloy smelting. Specifically, it is a method for improving the mechanical properties of aluminum-silicon-magnesium casting alloys. Background technique [0002] ZL101 casting alloy has good fluidity and low thermal expansion coefficient, and is used to manufacture castings with complex shapes, such as automobile hubs, housings, boxes and mechanical brackets. In order to solve the problem of coarse eutectic silicon and coarse aluminum grains in industrial production, the modification method of adding aluminum-titanium-boron refiner and aluminum-strontium modifier to the melt is often used. This process can better improve the structure and improve the mechanical properties, but because the low-melting point strontium is prone to volatilization and oxidation during high-temperature smelting and pouring, resulting in pores, inclusions and even reduced metamorphic effects in the alloy, resulting in fluctuatio...

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Problems solved by technology

In contrast, the metamorphism of heavy rare earths is better than that of light rare earths, but the cost of raw materials is relatively high

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