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Improvement of mechanical properties of Al6061 extrudate by die cooling with N2 gas during hot extrusion

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Abstract

In this study, the mechanical properties of the extrudate are improved by correcting the defects such as abnormal grain growth (AGG). Die cooling with N2 gas is conducted to control the extrusion temperature during the hot extrusion of Al6061 in order to obtain fine grains of the extrudate. Computational fluid dynamics (CFD) is conducted to evaluate the effect of die cooling with N2 gas and to determine the relationship between AGG and the extrusion temperature. The optimal cooling channel with a high cooling effect is designed by using the design of experiment (DOE) method, and thermo-mechanical analysis is performed to predict the extrusion temperature. A hot extrusion experiment is also carried out to measure the extrusion temperature and to observe the microstructure of the extrudate. The extrusion temperature predicted from the thermo mechanical analysis is found to be in good agreement with the measured extrusion temperature. The process condition required to reduce the AGG is determined on the basis of the distribution of the evolved microstructure in the hot extrusion experiment. The results confirm the relationship between the distribution of AGG and the mechanical properties of the extrudate. It is confirmed that the mechanical properties of Al6061 can be improved by the application of die cooling with N2 gas during the hot extrusion process.

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Correspondence to Byung-Min Kim.

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Recommended by Editor Sung-Lim Ko

Dae-Hoon Ko is currently a Ph.D candidate at the Precision Manufacturing Systems Division at Pusan National University in Busan, South Korea. His current research interests hot extrusion and heat treatment of aluminum alloys.

Byung-Min Kim received his B.S., M.S. and Ph.D degrees from Pusan National University, South Korea, in 1979, 1984 and 1987, respectively. He is currently a professor at the School of Mechanical Engineering at Pusan National University in Busan, Korea.

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Ko, DH., Kang, BH., Ko, DC. et al. Improvement of mechanical properties of Al6061 extrudate by die cooling with N2 gas during hot extrusion. J Mech Sci Technol 27, 153–161 (2013). https://doi.org/10.1007/s12206-012-1213-x

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  • DOI: https://doi.org/10.1007/s12206-012-1213-x

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