Thermal characteristics of induction heating with stepped diameter mold during two-phase zone continuous casting high-strength aluminum alloys

With the rapid surge in demand for high-strength aluminum alloy materials, there is an urgent need to address the different problems associate with the manufacturing of such materials to ensure the production of high-performance aluminum alloys. Conventional continuous casting is one of the widely used methods for the preparation of high-strength aluminum alloys. Unfortunately, aluminum alloys produced by this technique are highly susceptible to hot tearing and poor cold workability due to defects induced by nonuniform and weaker mechanical properties. Recent studies have revealed that the problem of hot tearing during continuous casting of high-strength aluminum alloys can be avoided by effectively controlling the temperature filed and solidification in the mushy zone – a zone that comprises solid and liquid phases.

Two-phase zone continuous casting (TZCC) has been recently identified as a promising technique for controlling the temperature of the mold and solidification in the mushy zone during the processing of alloys due to the advantage of the wide solidification interval. Consequently, induction heating has exhibited the great potential of ensuring uniform temperature distribution, considering that it is highly affected by the electromagnetic field as well as the workpiece and coil structures. Equipped with this knowledge, a team of researchers from the University of Science and Technology Beijing: Dr. Yaohua Yang, Professor Xuefeng Liu, and Dr. Siqing Wang studied the influences of mold structures on the induction heating and temperature field during the two-phase zone continuous casting process. Their main objective was to provide a guideline for the continuous casting of high-performance alloy materials. Their work is currently published in the International Journal of Heat and Mass Transfer.

In their approach, a three-dimensional two-phase zone continuous casting model was first established and verified to determine the temperature field during the casting process. Moreover, the finite element method was used to analyze the influence of the mold structure and temperature on the magnetic field and melt zone. Furthermore, the designed molds were used to cast 2D12 aluminum alloy continuously. Lastly, the surface quality and microstructures of the resulting aluminum alloy were analyzed, and the calculated and measured results were compared to validate the feasibility of the proposed model.

Results showed that the calculated temperature field was comparable to the measured values, an indication of the reliability and feasibility of the proposed model for calculating the temperature. Moreover, the authors observed an enhanced uniformity in the magnetic field in the mold attributed to the weakening of the electromagnetic coupling by the grooves in the stepped diameters molds. Similarly, stronger electromagnetic coupling exhibited in the convex plate in the stepped diameter mold led to an increase in the vertical temperature gradient in the mushy zone. Using the calculated results, a high-performance 2D12 aluminum alloy bar was successfully processed using the two-phase zone continuous casting technique.

In summary, the study investigated the thermal characteristics of induction heating during the two-phase zone continuous casting of high strength aluminum alloys. Based on the calculation results, the proposed technique was successfully used to process a high-performance 2D12 aluminum alloy bar. In a statement to Advances in Engineering, the authors acknowledged that the insights provided in the study would advance the design and fabrication of high-performance materials alloys for various applications.