The ingot produced by hot top casting for aluminum has good internal quality, uniform structure, and high mechanical properties, especially the edges of the ingot. This is because the effective crystallization height of the hot top mold is very small, the cooling rate of the ingot is increased, the liquid cavity of the ingot becomes shallower, and the excessive band is narrowed, so the density of the ingot is increased, and the chemical composition is distributed along the cross-section of the ingot. The hot top casting method can achieve the same level of casting, it is convenient to use the melt purification treatment device, and can control the re-contamination of the melt during the casting, and the oxide on the surface of the melt is not easy to be involved in the melt during the casting process.
In terms of metal transfer, hot top casting for aluminum eliminates the funnel and realizes lateral flow. The metal liquid level in the hot top and the metal liquid level in the flow plate is kept at the same level, realizing stable short mold casting and same level casting. The oxide film on the liquid surface in the crystallizer is stable without agitation, thus effectively preventing the secondary pollution of the melt and improving the internal purity of the metal.
The surface of the produced ingot is smooth, and the degree and depth of inverse segregation around the ingot are greatly reduced. Because during hot top casting, the countercurrent cooling effect of the secondary cooling water is relatively sufficient, which effectively prevents the secondary remelting of the condensate, thereby inhibiting the generation of segregation tumors. At the same time, during the casting process, the ingot head always maintains the stable liquid column, reduces the solidification position of the melt in the crystallizer, effectively prevents the premature cooling of the metal surface, stabilizes the meniscus, and effectively inhibits the formation of cold barriers.