Method for improving fluidness of magnesium alloy melt and special agitating apparatus

Abstract

The invention discloses a method for improving fluidity of magnesium alloy melts on the basis of revealing the isothermal viscosity changing law of magnesium alloy melts containing calcium and also discloses a special stirring device. The method composes the following steps: (1) the magnesium alloy and Mg-Ca master alloy are heated and melted to obtain overheat magnesium alloy melt containing calcium; and (2) the overheat magnesium alloy melt containing calcium is transferred to a holding furnace for stirring treatment. The 'modification+stirring' composite technology processing treatment is carried out on the overheat magnesium alloy melt and the effect is not a simple cumulative effect but a superimposed compound effect, so the method makes full use of advantages of two melts processing treatment and effectively improves the structure property and fluidity of alloys. The method has the advantages of simple technology, wide application scope, and the like.

Description

technical field [0001] The invention belongs to the technical field of magnesium alloy production, and relates to the viscosity change rule and processing method of magnesium alloy melt, in particular to a method for improving the fluidity of magnesium alloy melt and a special stirring device. Background technique [0002] Magnesium alloys are widely used in automobiles, communications, electronics and other fields due to their excellent shock absorption performance, good casting performance, high specific strength and specific stiffness. At present, with the rapid development of lightweight technology, higher requirements are put forward for the comprehensive performance of magnesium alloys. How to further improve the alloy structure and formability is a common concern of the majority of researchers. [0003] AZ91D magnesium alloy is one of the most widely used casting magnesium alloys, and the amount used in die casting magnesium alloys alone accounts for nearly 90%, showi...

AI Technical Summary

Problems solved by technology

By increasing the content of Al in AZ91D magnesium alloy, its fluidity can be improved, but when the content of Al exceeds 10%, the plasticity of magnesium alloy will be greatly reduced; adding a small amount of calcium element in AZ91D magnesium alloy can significantly reduce its oxidation tendency, refine Grain and grain boundary structure, improve fluidity and reduce heat treatment sensitivity, but when the added calcium element exceeds a certain amount, it will greatly increase the tendency of the alloy to produce brittleness and hot cracking; and the method of compound addition of alloy elements can also improve AZ91D The fluidity of the magnesium alloy melt, but the ratio of the added elements is not easy to control reasonably, and may even bring about other effects, such as Ti element is unfavorable to corrosion resistance, Be element is toxic, etc.

Therefore, the ideal effect is often not achieved only by reasonably controlling the addition of alloying elements, and it needs to be supplemented by other melt processing methods.

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