Papers by Author: Jian Zhong Cui

Abstract: The aluminium alloy bar is mainly obtained by hot extrusion in the past. In order to increase the production efficiency and reduce the cost, a new mold is designed, and horizontal continuous casting is used to produce the aluminium alloy bar in this work. The results show that aluminium alloy bar can be cast by horizontal continuous casting. The asymmetry of the sump is overcome by optimizing the design of the mold. When the temperature of the melt was 730°C, casting speed is 650 mm/min, cooling water is 15 L/min, the quality of lubricating oil is 0.5 ml/min, and the ingot with good surface quality can be cast.

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: The effects of DC and AC magnetic field on the phase composition, morphology and distribution of the ternary Al-Fe-Si alloy were investigated. The solidification structures of the alloy solidified with and without the application of magnetic fields were confirmed by DSC and structural measurements. The results showed that, in this Al-Fe-Si alloy the fine needle-like Al3Fe phase dominated the microstructure at the grain boundaries with the minor amount of Chinese script-like α-AlFeSi. Distribution of Al₃Fe phase was almost homogeneous in the volume of the sample when alloy was solidified in the conventional condition. When the DC magnetic field was imposed, distribution of Al₃Fe phase was more homogeneous. However, the Al₃Fe and α-AlFeSi phases were accumulated towards the center of the sample with the application of the AC magnetic field. This is due to the difference of Lorentz force between Al matrix and iron-containing intermetallics. Furthermore, the amount of Chinese script-like α-AlFeSi was increased remarkably under AC magnetic field.

Abstract: The rules of the distribution of magnetic field were carried out by numerical simulation. The distribution of magnetic field was got, and the effects of current intensity and frequency on the distribution of magnetic field were analyzed by constructing three-dimensional finite element model and using ANSYS software which is a kind of commercial FEM analysis software. The results show that the intensity of magnetic field is proportional to current intensity, magnetic field is mainly localized in the surface region of liquid melt and there is a notable edge effect in the corner.

Abstract: On the basis of conventional hot-top casting and Casting, Refining and Electromagnetic process, a lower frequency electromagnetic field was applied during the hot-top casting process. A comprehensive two-dimensional (2-D) mathematical model based upon the ANSYS and FLUENT has been developed for the computation of the electromagnetic field, solidification, fluid flow and heat transport during conventional and low frequency electromagnetic hot-top casting processes. The results show that there is a good agreement between the experimental results and calculated results.