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

Significance 

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.

Thermal characteristics of induction heating with stepped diameter mold during two-phase zone continuous casting high-strength aluminum alloys - Advances in Engineering
Fig. 1 The FE model of TZCC for preparing aluminum alloys bar (a) 3 D FE model, model and real object of the graphite mold (b) and (d) A type, (c) and (e) B type, (d) and (f) C type.
Thermal characteristics of induction heating with stepped diameter mold during two-phase zone continuous casting high-strength aluminum alloys - Advances in Engineering
Fig. 2 2D12 aluminum alloy bars prepared by TZCC technique under controlled mold temperature of 823 K for different molds (a) surface quality and microstructures of the aluminum bar by (b) OM and (c) SEM in BSE mode.

About the author

Xuefeng Liu is a professor in the Department of Materials Processing and Control Engineering, School of Materials Science and Engineering at University of Science and Technology Beijing (USTB). He received his BS and PhD from Department of Metallurgical and Material Engineering at Chongqing University in 1993 and 2001, respectively. In 2002, he was promoted to associate professor during his post-doctoral research in Sichuan University. In 2003, he began to work in the School of Materials Science and Engineering at USTB. In 2006, he was promoted to professor and now he is the dean of Research Institute of Science and Technology at USTB. He has long been engaged in the research of new technology and theory of high performance and difficult-to-machine metal materials in short process with high efficiency.

He has opened up new fields of Temperature controlled mold continuous casting, Intelligent semi-constrained plastic forming, Short-process controlled forming of metal laminated composites, Liquid metal flow rapid cooling additive manufacture and Nanometer photocatalytic plating at the forefront of international research. He has authored or coauthored more than 160 peer-reviewed journal papers, applied one international PCT invention patent and 66 invention patents have been authorized. More than 10 invention patents have been transferred to many enterprises, and a variety of high-performance new materials and precision parts have been applied in the major and key projects.

About the author

Yaohua Yang is lecturer in the Department of Materials Processing and Control Engineering, School of Materials Science and Engineering at University of Science and Technology Beijing (USTB). He received his BS from Shenyang University of Technology in 2012, MS from Northeastern University in 2014 and PhD from Harbin Institute of Technology in 2018. He began his post-doctoral research in School of Materials Science and Engineering, USTB, and his postdoctoral co-supervisor is Professor Xuefeng Liu.

He is mainly engaged in the research of new technology and theory of controlled solidification and forming of high-performance metal materials, and has authored or coauthored more than 20 peer-reviewed journal papers, applied 3 invention patents. For more information.

Reference

Yang, Y., Liu, X., & Wang, S. (2020). Thermal characteristics of induction heating with stepped diameter mold during two-phase zone continuous casting high-strength aluminum alloysInternational Journal of Heat and Mass Transfer, 152, 119479.

Go To International Journal of Heat and Mass Transfer

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