Studies on the Hot Forming and Cold-Die Quenching of AA6082 Tailor Welded Blanks

Abstract:

An advanced forming process involving hot forming and cold-die quenching, also known as HFQ®, has been employed to form AA6082 tailor welded blanks (TWBs). The HFQ® process combines both forming and heat treatment in a single operation, whereby upon heating the TWB, it is stamped and held between cold tools to quench the component to room temperature. The material therefore undergoes temperature, strain rate or strain path changes during the operation. In this paper, a finite element model (FEM) was developed to investigate the formability and deformation characteristics of the TWBs under HFQ® conditions. Experimental results, i.e. strain distribution, were used to compare and validate the simulation results. A good agreement between the experiment and simulation has been achieved. The developed temperature, strain rate and strain path dependent forming limit prediction model has been implemented into FE simulation to capture the complicated failure features of the HFQ® formed TWBs. It is found from both experiment and simulation that the forming speed has important effects on the occurrence of failure position, where the failure mode for the 1.5-2 mm TWBs may change from localised circumferential necking to parallel weld necking.HFQ® is a registered trademark of Impression Technologies Ltd.

• Periodical: Key Engineering Materials (Volume 716)
• Pages: 941-947
• DOI: https://doi.org/10.4028/www.scientific.net/KEM.716.941
• Online since: October 2016
• Authors: Jun Liu, Ai Ling Wang, Hao Xiang Gao, Omer El Fakir, Xi Luan, Li Liang Wang*, Jian Guo Lin
• Keywords: Aluminium, Failure Prediction, Finite Element Model, Hot Stamping, Tailor Welded Blank

References

[1] J. Liu, L. Wang, J. Lee, R. Chen, O. El-Fakir, L. Chen, J. Lin, T.A. Dean, Size-dependent mechanical properties in AA6082 tailor welded specimens, J. Mater. Process. Tech. 224 (2015) 169-180.

DOI: 10.1016/j.jmatprotec.2015.05.004

[2] A.A. Zadpoor, J. Sinke, R. Benedictus, Mechanics of Tailor Welded Blanks: An Overview, Key Eng. Mater. 344 (2007) 373-382.

DOI: 10.4028/www.scientific.net/kem.344.373

[3] J. Liu, H. Gao, O. El Fakir, L. Wang, J. Lin, Hot stamping of AA6082 tailor welded blanks: experiment and FE simulation, Manufacturing Rev. 3 (2016) 8.

DOI: 10.1051/mfreview/2016009

[4] Z. Marciniak, K. Kuczyński, Limit strains in the processes of stretch-forming sheet metal, Int. J. Mech. Sci. 9 (1967) 609-620.

DOI: 10.1016/0020-7403(67)90066-5

[5] R.W. Davies, G.J. Grant, M.A. Khaleel, M.T. Smith, H.E. Oliver, Forming-limit diagrams of aluminum tailor-welded blank weld material, Metall. Mater. Trans. A 32 (2001) 275-283.

DOI: 10.1007/s11661-001-0259-7

[6] O. El Fakir, L. Wang, D. Balint, J.P. Dear, J. Lin, Predicting Effect of Temperature, Strain Rate and Strain Path Changes on Forming Limit of Lightweight Sheet Metal Alloys, Procedia Eng. 81 (2014) 736-741.

DOI: 10.1016/j.proeng.2014.10.069

[7] M.S. Mohamed, A.D. Foster, J. Lin, D.S. Balint, T.A. Dean, Investigation of deformation and failure features in hot stamping of AA6082: Experimentation and modelling, Int. J. Mach. Tool. Manu. 53 (2012) 27-38.

DOI: 10.1016/j.ijmachtools.2011.07.005

[8] X. Luan, O.E. Fakir, H. Gao, J. Liu, L. Wang, Formability of AA6082-T6 at warm and hot stamping conditions, 16th International Conference Metal Forming, Kraków, Poland, (2016).

DOI: 10.4028/www.scientific.net/kem.716.107

[9] J. Lin, T.A. Dean, Modelling of microstructure evolution in hot forming using unified constitutive equations, J. Mater. Process. Tech. 167 (2005) 354-362.

DOI: 10.1016/j.jmatprotec.2005.06.026