Research on vibration technology in casting forming

More than 100 years ago, Chernoff applied vibration during ingot forming, and the grain of ingot casting was refined. With the development of vibration technology, vibration has been applied in extrusion forming, vibration welding, vibration stress relief and casting forming technology. Through the research of scholars from various countries, the vibration theory has developed rapidly. Vibration is applied in the solidification process of liquid metal, which breaks and refines the crystalline structure of the casting, reduces the residual stress of the casting, and improves the mechanical properties of the casting. In the casting process, it is generally expected to obtain fine equiaxed crystal structure. The principle is that new crystal nuclei are constantly generated in the liquid, which hinders the unidirectional extension of dendrites and obtains fine grain structure.

Foreign scholars have studied the application of vibration technology in casting and forming. Chaowalit limmaneevichitr and other B knives have studied aluminum alloy casting, observed the solidification structure of castings under the condition of vibration, and studied whether vibration casting can replace semi-solid casting. S. Maleksaeedi et al. 9 studied the effect of vibration on filtration rate and blank density by applying vibration to the forming process of submicron aluminum oxide powder. 5. Oabramov et al. Studied the effects of electromagnetic force and ultrasonic vibration on the properties of aluminum lead alloy in the casting process, and came to the conclusion that the best comprehensive mechanical properties and wear resistance can be obtained by treating the evenly distributed aluminum lead alloy with electromagnetic force and ultrasonic vibration.

Domestic experts have also done a lot of work on the influence of vibration technology on casting forming. Pandy et al. Used vibration in the casting of zlioi aluminum alloy. The research results show that the grain size is large when the mold is stationary. When vibration is applied, only the dendrite is broken, the grain size becomes smaller and the tensile strength increases. With the increase of vibration frequency, the pinhole rate in the casting decreases, and the tensile strength first increases and then tends to be stable. Yang Zhijie and others studied the effect of vibration on the microstructure of copper castings. The results showed that when there was no vibration, there was almost no equiaxed crystal in the casting, and the equiaxed crystal increased with the increase of frequency. Wang Chengjun and others studied the influence of vibration on casting forming by using the multi degree of freedom vibration platform. The research results show that when the amplitude changes, the average grain area and the number of equiaxed grains of solidification structure change irregularly. When the amplitude is 5mm, the vibration effect is the best, and the influence of frequency on casting structure is more obvious than that of amplitude. In order to explore the change of graphite morphology, Li Junwen and others applied ultrasonic to the melt of gray cast iron. The research results showed that the microstructure treated by ultrasonic was mainly composed of coarse graphite; With the increase of ultrasonic treatment time, graphite becomes smaller, but the treatment time is not too long.

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