A New Coupled Thermal Stress FE-Model for Investigating the Influence of Non-Isothermal Conditions on Bond Strength and Bonding Status of the First Pass in Roll Bonding

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Abstract:

Roll bonding is a joining-by-forming process to permanently join two or more layers of different materials by hot or cold rolling. One of the typical industrial applications is aluminium sheets for heat exchangers in automobiles. During roll bonding the layers are fed into the rolling stand with parallel surfaces. Due to the plastic deformation in the roll gap metallic bonds between the layers are achieved. Several theoretical models have been published to describe the process, e.g. Zhang & Bay. These models have mostly been developed for cold rolling and describe the bond strength based on surface enlargement, contact pressure and flow stress. Since these models are developed for cold rolling, they are not temperature depending. Heat exchange is usually neglected and de-bonding after the roll gap is not accounted for. However, for hot roll bonding the above mentioned assumptions do not hold true. To understand the mechanisms of hot roll bonding industrial and laboratory scale investigations have previously been conducted. Based on the findings a FE framework for hot roll bonding was developed. This FE framework accounts for the possibility of de-bonding after the roll gap but is restricted to isothermal conditions. However, for a roll bonding simulation it is essential to take the temperature influence into consideration. Therefore, this paper presents an extended version of the FE framework which accounts for temperature dependent material flow, compatible definition of thermal & mechanical interactions and bonding status related heat exchange. To verify the new features of the extended FE framework a roll bonding test case is employed. Mechanical and thermal interactions as well as the current flow stress are calculated in subroutines in order to enable a fully coupled thermal stress simulation. The results show that with this extended FE framework the influence of non-isothermal conditions on material flow and bonding status as well as the feedback effects of bonding status to heat exchange have been successfully integrated in hot roll bonding simulations. This fully coupled thermal stress simulation is the first step towards multi-pass roll bonding simulations.

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301-308

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April 2018

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[1] N. Bay, C. Clemensen, O. Juelstrop, Bonding stress in cold roll bonding, Annals of the CIRP Vol. 34/1/(1985).

DOI: 10.1016/s0007-8506(07)61760-0

Google Scholar

[2] J. Hirsch, Walzen von Flachprodukten, Wiley-VCH, Weinheim, (2001).

Google Scholar

[3] L. Chen, Z. Yang, B. Jha, G. Xia, J. W. Stevenson, Clad metals, roll bonding and their applications for SOFC interconnects, Journal of Power Sources 152 (2005) 40–45.

DOI: 10.1016/j.jpowsour.2005.01.055

Google Scholar

[4] M. Bambach, M. Pietryga, A. Mikloweit, A finite element framework for the evolution of bonding stress in joining-by-forming processes, Journal of Material Processing Technology 214 (2014) 2156-2168.

DOI: 10.1016/j.jmatprotec.2014.03.015

Google Scholar

[5] W. Zhang, N. Bay, A Numerical Model for Cold Welding of Metals, Annals of the CIRP Vol. 45/1/(1996).

Google Scholar

[6] A. Mikloweit, M. Bambach, M. Pietryga, G. Hirt, Development of a testing procedure to determine the bonding stress in joining-by-forming process, Advanced Material Research Vols. 966-967 (2014) pp.481-488.

DOI: 10.4028/www.scientific.net/amr.966-967.481

Google Scholar

[7] M. Pietryga, J. Lohmar, G. Hirt, A New FE-Model for the Investigation of Bond Formation and Failure in Roll Bonding Process, Material Science Forum 854, 2016, 152-157.

DOI: 10.4028/www.scientific.net/msf.854.152

Google Scholar

[8] C. Yue, L. Zhang, J. Ruan, H. Gao, Modelling of recrystallization behavior and austenite grain size evolution during the hot rolling of GCr15 rod", Applied Mathematical Modelling 34 (2010) 2644–2653.

DOI: 10.1016/j.apm.2009.12.001

Google Scholar

[9] D. R. Cooper, J. M. Allwood, The influence of deformation conditions in solid-state aluminium welding processes on the resulting weld strength, Journal of Materials Processing Technology 214 (2014) 2576–2592.

DOI: 10.1016/j.jmatprotec.2014.04.018

Google Scholar

[10] Information on http://abaqus.software.polimi.it/v6.14/books/usb/default.htm.

Google Scholar

[11] R. Kopp, H. Wiegels, Introduction to forming technology, second ed., Mainz, Aachen, (1999).

Google Scholar

[12] H. Yüncü, Thermal contact conductance of nominaly flat surfaces, Heat Mass Transfer (2006) 43: 1–5.

DOI: 10.1007/s00231-006-0087-9

Google Scholar

[13] A. Melzner, G. Hirt, Determination of thermal boundary conditions for modeling the hot roll bonding process, Key Engineering Materials Vol. 651-653 (2015), pp.1357-1362.

DOI: 10.4028/www.scientific.net/kem.651-653.1357

Google Scholar