Papers by Keyword: Hot-Top Casting

Abstract: Low frequency electromagnetic (LFE) field was applied during the conventional hot-top casting process. Thermocouples were used to measure the cooling curves from the border to the center of the ingot during steady-state of casting process, cooling curves were obtained, and effects of low frequency electromagnetic field on the solidification, macrostructure during the conventional hot-top casting for 6063 aluminum alloy process were analyzed. The experimental results show that the forced convection caused by the low frequency electromagnetic (LFE) filed can make the melt temperature uniform, promote the evacuation of superheat, make the temperature in the liquid pool lower than the liquidus temperature of 6063 aluminum alloy, increase the number of floating nuclei, make the ingot with fine and homogeneous macrostructure, though there is no addition of any grain refiners.

Abstract: Surface segregation layer are frequently encountered during aluminium alloy direct chill casting process, and the removal of the surface segregation layer before further processing of the ingot decreases the ingot yield. In this work, the low frequency electromagnetic field was applied to study the effects of low frequency electromagnetic field on segregation layer during the direct chill casting process. The results show that under the effect of the low frequency electromagnetic field, the surface quality of ingot is improved, the structure of the ingot is refined, and the thickness of segregation layer is decreased.

Abstract: On the basis of conventional hot-top casting, low frequency electromagnetic field was applied in the process of hot-top casting to produce 7050 aluminum alloy ingot, the influences of low frequency electromagnetic field on cold-shut have been studied. The experimental results show that under the effect of the low frequency electromagnetic filed, the depth of cold folding has been decreased, and the as-cast structure has been refined. The reasons for low frequency electromagnetic field improving the surface quality, refining the structure of the ingot were summarized.

Abstract: Hot tear is one of the main defects during the aluminium casting process, and it usually occurs during solidification. In this work, the low frequency electromagnetic field was applied to study the effects of low frequency electromagnetic field on hot tear during the conventional hot-top casting process. The results show that under the effect of the low frequency electromagnetic field, the structure of the ingot is refined, the flow direction is changed, and the depth of the sump becomes shallow. All these factors can decrease the hot tear susceptibility.