Variable frequency ultrasonic semi-continuous casting method for magnesium alloy

Abstract

The invention belongs to the field of light alloy machining, and particularly relates to a variable frequency ultrasonic semi-continuous casting method for magnesium alloy. The method comprises the steps of alloy smelting, melt delivery and consolidation forming under ultrasonic treatment. Magnesium alloy melt is treated in a real-time variable frequency ultrasonic field introduced in the semi-continuous casting process, and the quasi real-time tracking of the resonant frequency of metal melt is achieved; and liquid cave melt is subjected to the ultrasonic resonance treatment continuously in the whole semi-continuous casting process, so that the continuous ultrasonic high-efficiency treatment of the magnesium alloy melt is achieved in the solidification process. In the method provided by the invention, an ultrasonic radiation rod is extended into the magnesium alloy melt in the magnesium alloy semi-continuous casting process, so that the cavitation effect and acoustic streaming effect produced by the variable frequency ultrasonic field directly act on the magnesium alloy melt solidifying. With the method provided by the invention, the magnesium alloy solidification behavior can be changed obviously, the structure is refined, and the uniformity of the billet solidification structure as well as the mechanical property of magnesium alloy billets are improved; and the billet casting defects are reduced obviously, and the quality of the magnesium alloy billets is improved greatly.

Description

technical field [0001] The invention belongs to the field of light alloy processing, in particular to a magnesium alloy frequency conversion ultrasonic semi-continuous casting method. [0002] technical background [0003] Magnesium alloy has the advantages of light density, high specific strength and specific stiffness, good electromagnetic shielding, good damping performance, etc., making it widely used in many fields such as transportation, aerospace, national defense technology and 3C electronics, and is known as "21 The green engineering material of the century". [0004] Semi-continuous casting is the main production method of magnesium alloy ingots at present. Its basic principle is to introduce the magnesium alloy melt into the crystallizer cooled by circulating water. It is pulled out and water spray cooling is continued until an ingot is formed. Semi-continuous casting has the advantages of high productivity, low casting cost and simple operation. [0005] Howeve...

AI Technical Summary

Problems solved by technology

Due to the severe attenuation of the ultrasonic field in the magnesium alloy melt, the range of action of the ultrasonic field is limited, so that the range of action is limited to a small area near the ultrasonic emitting surface, which is not conducive to the production of large-diameter ingots

At the same time, since the physical parameters of the melt in semi-continuous casting production are not constant, the resonant frequency of the melt will change. The existing fixed-frequency ultrasonic field is difficult to overcome the weakening of the acoustically induced nonlinear effect due to the change of the resonant frequency. The phenomenon

Therefore, the effects of grain refinement and uniform structure brought by the ultrasonic field cannot be fully utilized.

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