Investigation of the Formability of Flanged Parts of Magnesium Alloy under Hot Forging Process

Abstract:

This study investigated the mechanical properties and forming characteristics of flanged parts made of AZ61 magnesium alloys via hot working. The bearing cover of the gearbox in cars was selected as a carrier in hot forging to probe into the formability of magnesium alloys. A high-speed metal test machine was used for compression tests under different forming temperatures and strain rates to obtain stress-strain curves. The stress-strain data are applied to the Finite Element Method to analyze the formability of the bearing cover. Finally, based on the comparison of simulation and experimental results, we conclude that under the same billet heating temperature and low strain rate, the forming load was small and no cracks developed on the flanges of forged parts. However, under the same condition, the microstructure of the part was coarse. This study also attempted to identify a method for manufacturing a bearing cover with a low forging load, and determined how temperature influences hardness and microstructure of the bearing cover.

• Periodical: Advanced Materials Research (Volumes 83-86)
• Pages: 67-76
• DOI: https://doi.org/10.4028/www.scientific.net/AMR.83-86.67
• Online since: December 2009
• Authors: Huey Lin Ho, Su Hai Hsiang, Zun Yao Huang
• Keywords: Compression Test, Gearbox Bearing Cover, Magnesium Alloy, Strain Rate

References

[1] H. Friedrich and S. Schumann , Research for a new age of magnesium, in the automotive industry, J. Mater. Process. Technol. Vol. 117 (2001), p.276 ~ 281.

[2] E. Aghion, B. Bronfin and D. Eliezer, The role of the magnesium industry in protecting the environment, J. Mater. Process. Technol. Vol. 117 (2001), p.381 ~ 385.

DOI: 10.1016/s0924-0136(01)00779-8

[3] N. Ogawa, M. Shiomi and K. Osakada, Forming limit of magnesium alloy at elevated temperatures for precision forging, J. Mater. Process. Technol. Vol. 42 (2002), p.607 ~ 614.

DOI: 10.1016/s0890-6955(01)00149-3

[4] R. Ye. Lapovok and M. R. Barnett, Construction of extrusion limit diagram for AZ31 magnesium alloy by FE simulation, J. Mater. Process. Technol. Vol. 146 (2004), p.408 ~ 414.

DOI: 10.1016/j.jmatprotec.2003.12.003

[5] Margam Chandrasekaran and Yong Ming Shyan John, Effect of materials and temperature on the forward extrusion of magnesium alloys, Materials Science and Engineering A Vol. 381 (2004), p.308 ~ 319.

DOI: 10.1016/j.msea.2004.04.057

[6] L. Li, J. Zhou and J. Duszczyk, " Determination of a constitutive relationship for AZ31B magnesium alloy and validation through comparison between simulation and real extrusion, J. Mater. Process. Technol. Vol. 172 (2006), p.372 ~ 380.

DOI: 10.1016/j.jmatprotec.2005.09.021

[7] Hu Yamin, Lai Zhouyi and Zhang Yucheng, The study of cup-rod combined extrusion process of magnesium alloy (AZ61A), J. Mater. Process. Technol. 187-188 (2007), p.649 ~ 652.

DOI: 10.1016/j.jmatprotec.2006.11.054

[8] K. Mueller and S. Mueller, Severe plastic deformation of the magnesium alloy AZ31, J. Mater. Process. Technol. Vol. 187-188 (2007), p.775 ~ 779.

DOI: 10.1016/j.jmatprotec.2006.11.153

[9] G. Liu, J. zhou and J. Duszczyk, Prediction and verification of evolution as a function of ram speed during the extrusion of AZ31 alloy into a rectangular section, J. Mater. Process. Technol. Vol. 186 (2007), p.191 ~ 199.

DOI: 10.1016/j.jmatprotec.2006.12.033

[10] C. H. Lee and T. Altan, Influence of flow stress and friction upon metal flow in upset forging of ring and cylinders, J. Engineering for industry, Trans ASME, (1972), pp.775-782.

DOI: 10.1115/1.3428250

[11] M. R. Barnett, Influence of Deformation Conditions and Texture on the High Temperature Flow Stress of Magnesium AZ31, Journal of light Metals Vol. 1 (2001), pp.167-177.

DOI: 10.1016/s1471-5317(01)00010-4

[12] S. E. Ion, and F. J. Humphreys, Dynamic Recrystallisation and the Development of Microstructure During the High Temperature Deformation of Magnesium, Acta Metallurgica Vol. 30 (1982), p.1909-(1919).

DOI: 10.1016/0001-6160(82)90031-1