Effect of shielding gas on microstructure and mechanical properties in AA6061-T6 alloy MIG welding

Eren Yılmaz, Fehim Fındık

Abstract


Due to its properties such as high strength/weight ratio, enhanced corrosion resistance, low density, AA6061-T6 aluminum alloy welding is widely used in structural, automotive and rail industry. In this study, AA6061-T6 alloy was welded with robotic metal inert gas technique using ER5356 filler wire. The effects of different shielding gas composition ratios (argon/helyum) on the macro / microstructre, mechanical properties (hardness, tensile strength) of the weld joint were investigated. Welding porosity decreased with the addition of helium gas to argon gas. Accordingly, the tensile strength of welded joints increased from 190 MPa to 221 MPa with the addition of helium gas. The strength of the welded joints (190-221 MPa) was obtained lower than that of the base material (290 MPa) due to the changes in the microstructure as a result of the weld thermal cycle and grain coarsening in the heat affected zone. Dentritic, columnar and coarse shaped grains were observed along the weld section, respectively in the weld bead, partially melted zone and heat affected zone. The differentiation of the shielding gas composition did not cause these regions to change, but the heat affected zone expanded with the increase in the helium content. The change in hardness of the cross section of welded joint has increased from around 60 HV to 90 HV from the welding area to the base material. 25% Argon-75% Helium gas mixtures provided optimum combination in terms of microstructure, mechanical properties and cost.

Keywords


6061-T6 Aluminum alloy, MIG welding, Shielding gas, Porosity, ER5356

Full Text:

PDF

References


C.C. Menzemer, E. Hilty, S. Morrison, R. Minor, T.S. Srivatsan, ''Influence of post weld heat treatment on strength of three aluminum alloys used in light poles'', Metals (Basel), vol.6, pp. 1-15, 2016.

P. Li, F. Nie, H. Dong, S. Li, G. Yang, H. Zhang, ''Pulse MIG Welding of 6061-T6/A356-T6 aluminum alloy dissimilar T-joint'', Journal of Materials Engineering and Performance, vol.27, pp. 4760–4769, 2018.

M. Dewan, J. Liang, M. Wahab, A. Okeil, ''Post-weld residual stresses and heat treatments of Gas Tungsten Arc Welded aluminum alloy AA6061-T651'', World Journal of Engineering ,vol.10, pp. 11–22, 2013.

L. Purushothaman, P. Balakrishnan, ''Wear and corrosion behavior of coconut shell ash (CSA) reinforced Al6061 metal matrix composites'', Materials Testing, vol.62, pp. 77–84, 2020.

L. Zhang, H. Zhong, S. Li, H. Zhao, J. Chen, L. Qi, ''Microstructure, mechanical properties and fatigue crack growth behavior of friction stir welded joint of 6061-T6 aluminum alloy'', International Journal of Fatigue, vol.135, 105556, PP. 1-11, 2020.

R. Manti, D.K. Dwivedi, ''Microstructure of Al-Mg-Si weld joints produced by pulse TIG welding'', Materials and Manufacturing Processes, vol.22, pp. 57–61, 2007.

A. C. Munaz, G. Rückert, B.Huneau, X. Sauvage, S. Marya, ''Comparison of TIG welded and friction stir welded Al-4.5Mg-0.26Sc alloy'', Journal of Materials Processing Technology, vol.197, pp. 337-343, 2008.

A. Khoshroyan, A.R. Darvazı, ''Effects of welding parameters and welding sequence on residual stress and distortion in Al6061-T6 aluminum alloy for T-shaped welded joint'', Transactions Nonferrous Metals Society of China, vol.30, pp. 76–89, 2020.

K. S. Kumaran, S. O. N. Raj, ''Optimization of parameters involved in robotic MIG welding process based on quality responses'', IOP Conference Series: Materials Science and Engineering, vol.402, pp. 1-13, 2018

S. Baskutis, A. Žunda, R. Kreivaitis, ''Mechanical properties and microstructure of aluminium alloy AW6082-T6 joints welded by double-sided MIG process before and after aging'', Mechanika, vol.25, pp. 107–113, 2019.

J. Yı, G. Wang, S. L. Kang, Z. W. Lıu, Y. L. Gong, ''Effect of post-weld heat treatment on microstructure and mechanical properties of welded joints of 6061-T6 aluminum alloy'', Transactions of Nonferrous Metals Society of China, vol.29, pp. 2035–2046, 2019.

M. Toozandehjani, F. Mustapha, N.I. Zahari, M.K.A. Ariffin, K.A. Matori, F. Ostovan, W.F. Lim, ''Characterization of Aging Behavior of AA6061 Aluminum Alloy Through Destructive and Ultrasonic Non-destructive Testing Techniques'', Transactions of the Indian Institute of Metals, vol.68, pp. 561–569, 2015.

I. Guzman, E. Granda, J. Acevedo, A. Martinez, Y. Davilla, R. Velazquez, ''Comparative in mechanical behavior of 6061 aluminum alloy welded by pulsed GMAW with different filler metals and heat treatments'', Materials, vol.12, pp. 2-14, 2019.

M. Ishak, N.F.M. Fakhriah, ''The Effect of Filler ER4043 and ER5356 on Weld Metal Structure of 6061 Aluminium Alloy by Metal Inert Gas (MIG)'', International Journal of Engineering, Science and Technology, vol.3, pp. 1–7, 2015.

V.A. Mosneaga, T. Mizutani, T. Kobayashi, H. Toda, ''Impact toughness of weldments in Al-Mg-Si alloys'', Materials Transactions, vol.43, pp. 1381–1389, 2002.

Y. Liang, J. Shen, S. Hu, H. Wang, J. Pang, ''Effect of TIG current on microstructural and mechanical properties of 6061-T6 aluminium alloy joints by TIG–CMT hybrid welding'', Journal of Materials Processing Technology, vol.255, pp. 161–174, 2018.

C. Cai, S. He, H. Chen, W. Zhang, ''The influences of Ar-He shielding gas mixture on welding characteristics of fiber laser-MIG hybrid welding of aluminum alloy'', Optics Laser Technology, vol.113, pp. 37–45, 2019.

X. Cai, S. Lin, B. Wang, H. Dai, C. Fan, C. Yang, ''Droplet transfer and weld formation of MIG welding with Ar-He alternating gas for aluminum alloy'', Journal of Manufacturing Processes, vol.49, pp. 94–101, 2020.

B.Y. Kang, Y.K.D.V. Prasad, M.J. Kang, H.J. Kim, I.S. Kim, ''Characteristics of alternate supply of shielding gases in aluminum GMA welding'', Journal of Mater Processing Technology, vol.209, pp. 4716–4721, 2009.

M. Pakdil, G. Çam, M. Koçak, S. Erim, ''Microstructural and mechanical characterization of laser beam welded AA6056 Al-alloy'', Materials Science Engineering A., vol. 528, pp. 7350–7356, 2011.

P. Kah, J. Martikainen, ''Influence of shielding gases in the welding of metals'', International Journal Advanced Manufactring Technology, vol. 64, pp. 1411–1421, 2013.

V. Fahimpour, S.K. Sadrnezhaad, F. Karimzadeh, ''Corrosion behavior of aluminum 6061 alloy joined by friction stir welding and gas tungsten arc welding methods'', Materials Design, vol. 39, pp. 329–333, 2012

Y.M. Zhang, C. Pan, A.T. Male, ''Improved microstructure and properties of 6061 aluminum alloy weldments using a double-sided arc welding process'', Metallurgical and Materials Transactions A, vol.31, pp. 2537–2543, 2000.

N.K. Othman, S.R.S. Bakar, A. Jalar, J. Syarif, M.Y. Ahmad, ''The effect of filler metals on mechanical properties of 6 mm AA 6061-T6 welded joints'', Advanced Materials Research, vol. 154–155, pp. 873–876, 2011.

H.F. El-Labban, E.R.I. Mahmoud, ''Welding of AA 6028 aluminum alloy and its nanocomposite using different filler materials'', Materials Transactions, vol. 56, pp. 113–119, 2014.




DOI: http://dx.doi.org/10.21533/pen.v10i1.2159

Refbacks

  • There are currently no refbacks.


Copyright (c) 2022 Eren Yılmaz, Fehim Fındık

Creative Commons License
This work is licensed under a Creative Commons Attribution 4.0 International License.

ISSN: 2303-4521

Digital Object Identifier DOI: 10.21533/pen

Creative Commons License
This work is licensed under a Creative Commons Attribution 4.0 International License