Alumium alloy low frequency electromagnetic semi-continuous casting method and device

Abstract

The present invention belongs to the field of material processing technology. The equipment includes one crystallizer, one coil outside or inside the crystallizer with low-frequency current passing through. The semi-continuous aluminium alloy casting process in low-frequency electromagnetic field has electromagnetic field frequency of 15-50 Hz, casting temperature 680-750 deg.c, casting speed 50-150 mm / min and cooling water pressure 0.06-0.12 MPa. The present invention has fined crystal grains, full solid dissolving of alloy elements inside the crystal, no crack, no segregate, improved surface quality and high ingot quality.

Description

Technical field [0001] The invention belongs to the technical field of material processing Background technique [0002] Modern material preparation technology pursues low cost and high performance, that is, high performance price ratio. Modern material science tells us that a large number of defects in materials are produced during alloy casting, and a considerable part of the defects are difficult to repair in subsequent processing and heat treatment. Therefore, melting and casting is no longer just a means of material shaping, but more importantly, it is the first important link in material quality control. Fine grain and homogeneity are the basic directions for improving the performance of modern metal materials. The modern aluminum processing industry has higher and higher requirements for the quality of ingots. It is usually hoped to avoid cracks on the basis of ensuring the composition and size, so as to improve the yield; grain refinement, improve processability an...

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Problems solved by technology

Because this method has extremely high requirements on the stability of the casting machine, if the casting machine shakes slightly, there will be ripples on the surface, and the establishment of the casting start process is very difficult, thus limiting the industrial application of this technology

After that, new methods such as DC electromagnetic field, AC, and DC current were produced, but none of them became industrial technologies due to ineffective effects and complicated processes.

[0009] In 1986, the Frenchman Vives et al realized the electromagnetic casting of Φ320mm ingot of 2024 aluminum alloy by using the power frequency electromagnetic field, and found that the surface segregation was improved and the grains were refined. However, due to the limited penetration depth of the power frequency magnetic field, it had little effect on the internal structure. Especially the solid solution and segregation of alloying elements have little improvement

They also further used the electromagnetic oscillation technology [7] with the coexistence of DC and AC electromagnetic fields to make the grains of the ingot significantly refined. However, since the main frequency of the oscillation is twice the power frequency, the penetration depth of the magnetic field is limited. The structure has little effect, especially the solid solution and segregation of alloying elements have little improvement

In the future, over-pulse current and pulse magnetic field casting technology will be invented in China. However, due to the complexity of the pulsed magnetic field and the current device, the agitation is large when applied. Although the structure can be refined, the other properties of the ingot are not improved much, so the application is limited.

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