AZ91 magnezyum alaşımlarının sürtünme karıştırma nokta kaynağı; eksenel kuvvet ve dönme hızının kaynak kalitesine etkisi ve muayene planlamasına ilişkin bir yaklaşım

Bu çalışmada magnezyum alaşımlı (AZ91) sac malzemeler için sürtünme karıştırma nokta kaynağı işlemi incelenmiştir. Sürtünme karıştırma nokta kaynağı, katı hal kaynak işlemidir ve özellikle otomotiv bileşenlerini birleştirmek için kullanılan yenilikçi kaynak yöntemlerinden biridir. Son yıllarda magnezyum alaşımları, otomotiv uygulamalarına yönelik yapısal malzemelerde araç performansını artırmak ve emisyonları ve yakıt tüketimini azaltmak için yüksek mukavemet ve düşük yoğunluk kombinasyonunun gözlenebildiği umut verici malzemelerdir. Otomotiv uygulamalarında eksenel kuvvet ve dönme hızının malzeme üzerine etkisini anlamak için bir sonlu elemanlar modeligeliştirilmiştir. Sonlu elemanlar modeli ile 1 kN ile 8 kN arasında değişen eksenel kuvvetin ve 1000 rpm - 4000 rpm arasındaki dönme hızlarının etkisini araştırılmıştır. Model, işlem sonrasında süreksizlik oluşumuna yol açan ısı akışını ve sıcaklık artışını analiz etmektedir. 4,5 kN, 6 kN ve 8 kN eksenel kuvvetler ve 3000 rpm-4000 rpm dönme hızları, belirlenen sınır şartları altında süreksizlik oluşumu açısından kritik işleme parametreleri olarak değerlendirilmiştir. Son olarak, sürtünme karıştırma nokta kaynağı işleminden sonra yüzey ve hacimsel süreksizliklerin zararlı etkilerini ortadan kaldırmak için ve yapısal bütünlüğü sağlamak amacıyla çeşitli tahribatsız muayene yöntemleri önerilmiştir.

Anahtar Kelimeler:

Sürtünme karıştırma nokta kaynağı, Sonlu elemenalar analizi, Magnezyum alaşımı (AZ91), Eksenel kuvvet, Dönme hızı, Tahribatsız muayene

Friction stir spot weld (FSSW) of AZ91 magnesium alloys; effect of axial force and rotational speed on weld quality and an approach on inspection planning

In this study, the friction stir spot welding (FSSW) process for the magnesium alloy (AZ91) sheet materials are investigated. Friction stir spot welding (FSSW) is a solid-state welding process and one of the innovative methods to join specifically automotive components. Recently magnesium alloys are promising materials where combination of high strength and low density can be observed to improve vehicle performance and reduce emissions and fuel consumption in structural materials for automotive applications. A finite element model (FEM) established to understand the effect of axial force and rotational speed during the simulation in automotive applications. The FEM investigates the effect of axial force ranging from 1 kN to 8 kN and rotational speeds of 1000 rpm - 4000 rpm. The model analyses the heat flux and the temperature rise that leads defect formation after the process. 4.5 kN, 6 kN and 8 kN axial forces and 3000 rpm-4000 rpm rotational speeds are evaluated as the critical values in terms of defect and crack formation during the process under specified boundary conditions. Finally, several non-destructive inspection methods are suggested to secure structural integrity after the FSSW process to eliminate the harmful effects of surface and volumetric discontinuities.

Keywords:

Friction stir spot weld (FSSW), Finite element analysis (FEM), Magnesium alloy (AZ91), Axial force, Rotational speed, Nondestructive testing,

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X. W. Yang, T. Fu and W. Y. Li, Friction stir spot welding: a review on joint macro and microstructure, property, and process modelling. Advances in Materials Science and Engineering, 697170, 1–11, 2014. https://doi.org/10.1155/2014/697170.
M. A. Omar, The Automotive Body Manufacturing Systems and Processes. John Wiley & Sons Ltd., Chichester, UK, 2011.
J. Chen and Z. Feng, IR-based spot weld NDT in automotive applications. Proceedings, Thermosense: Thermal Infrared Applications XXXVII; 9485, Baltimore, United States, 2015. https://doi.org/10.1117/12.2177124.
M. M. Shtrikman, Current state and development of friction stir welding Part 3. Industrial application of friction stir welding. Welding International, 22, 806–815, 2008. https://doi.org/10.1080/09507110802593620.
O. Torun and I. Celikyurek, The effect of the friction pressure on the friction welding of AZ91 and Fe3Al alloys. The Eurasia Proceedings of Science, Technology, Engineering & Mathematics, 7, 175–180, 2019.
C. Blawert, N. Hort and K. U. Kainer, Automotive applications of magnesium and its alloys. Transactions of The Indian Institute of Metals, 57, 397–408, 2004.
M. Ciniviz and H. Köse, Hydrogen use in internal combustion engine: a review. International Journal of Automotive Engineering and Technologies, 1, 1–15, 2012.
P. Su, A. Gerlich, M. Yamamoto and T. H. North, Formation and retention of local melted films in AZ91 friction stir spot welds. Journal of Materials Science, 42, 9954–9965, 2007. https://doi.org/10.1007/s10853-007-2061-4.
A. Gerlich, P. Su and T. H. North, Peak temperatures and microstructures in aluminium and magnesium alloy friction stir spot welds. Science Technology of Welding and Joining, 10, 647–652, 2005. https://doi.org/10.1179/174329305X48383.
M. Yamamoto, A. Gerlich, T. H. North and K. Shinozaki, Liquid penetration induced cracking in Mg-alloy spot welds. Materials Science Forum, 580–582, 409–412, 2008. https://doi.org/10.4028/www.scientific.net/msf.580-582.409.
M. Yamamoto, A. Gerlich, T. H. North and K. Shinozaki, Cracking in dissimilar Mg alloy friction stir spot welds. Science and Technology of Welding and Joining, 13, 583–592, 2008. https://doi.org/10.1179/174329308X349520.
H. F. Zhang, L. Zhou and W. Li, Effect of tool plunge depth on the microstructure and fracture behavior of refill friction stir spot welded AZ91 magnesium alloy joints. International Journal of Minerals, Metallurgy and Materials, 28, 699–709, 2021. https://doi.org/10.1007/s12613-020-2044-x.
M. A. Constantin, A. Boşneag, M. Iordache, C. Bădulescu and E. Niţu, Numerical simulation of friction stir spot welding. Applied Mechanics and Materials, 834, 43–48, 2016. https://doi.org/ 10.4028/www.scientific.net/AMM.834.43.
P. Jedrasiak, H. R. Shercliff and A. Reilly, Thermal modeling of Al-Al and Al-Steel friction stir spot welding. Journal of Materials Engineering and Performance, 25, 9, 4089–4098, 2016. https://doi.org/10.1007/s11665-016-2225-y.
C. Ji, J. K. Na, Y. S. Lee, Y. Do Park and M. Kimchi, Robot-assisted non-destructive testing of automotive resistance spot welds. Welding in the World, 73, 6, 753–763. 2021. https://doi.org/10.1007/s40194-020-01002-1.
P. Buschke, W. Roye and T. Dahmen, Multiple NDT methods in the automotive industry. Huerth, Germany, 2002.
S. A. Titov, R. G. Maev and A. N. Bogachenkov, Pulse-echo NDT of adhesively bonded joints in automotive assemblies, Ultrasonics, 48, 6–7, 537–546, 2008. https://doi.org/10.1016/j.ultras.2008.07.001.
Z. Wu, X. Zhou, N. Ao, X. Han, Z. Zhu and S. Wu, Tensile and fatigue behaviors of hybrid laser welded A7N01 alloy with repairing for railway vehicles. Engineering Failure Analysis, 143, 1–15, 2023. https://doi.org/10.1016/j.engfailanal.2022.106930.
M. Thornton, L. Han and M. Shergold, Progress in NDT of resistance spot welding of aluminium using ultrasonic C-scan. NDT&E International, 48, 30–38, 2012. https://doi.org/10.1016/j.ndteint.2012.02.005.
H. Taheri, M. Kilpatrick, M. Norvalls, W. J. Harper, L. W. Koester, T. Bigelow and L. J. Bond, Investigation of nondestructive testing methods for friction stirwelding. Metals (Basel), 9, 6, 1–22, 2019. https://doi.org/10.3390/met9060624.
Y. K. Zhu, G. Y. Tian, R. S. Lu and H. Zhang, A review of optical NDT technologies. Sensors, 11, 8, 7773–7798, 2011. https://doi.org/10.3390/s110807773.
S. U. Khosa, T. Weinberger and N. Enzinger, Thermo-mechanical investigations during friction stir spot welding (FSSW) of AA6082-T6. Welding in the World, 54, 134–146, 2010. https://doi.org/10.1007/BF03263499.
P. Jedrasiak and H. R. Shercliff, Small strain finite element modelling of friction stir spot welding of Al and Mg alloys. Journal of Materials Processing Technology, 263, 18, 207–222, 2019. https://doi.org/10.1016/j.jmatprotec.2018.07.031.
M. Awang, V. H. Mucino, Z. Feng and S. A. David, Thermo-mechanical modeling of friction stir spot welding (FSSW). SAE International, 724, 2006. https://doi.org/10.4271/2006-01-1392.
M. Awang, Simulation of friction stir spot welding ( FSSW) process : study of friction phenomena, West Virginia University, USA, 2007.
Y. Sarikavak, An advanced modelling to improve the prediction of thermal distribution in friction stir welding (FSW) for difficult to weld materials. Journal of Brazilian Society of Mechanical Sciences and Engineering, 43, 4, 1-14 2021. https://doi.org/10.1007/s40430-020-02735-2.
M. Yamamoto, A. Gerlich, T. H. North and K. Shinozaki, Mechanism of cracking in AZ91 friction stir spot welds. Science and Technology of Welding and Joining, 12, 3, 208–216, 2007. https://doi.org/10.1179/174329307X177900.
M. Yamamoto, A. Gerlich, T. H. North and K. Shinozaki, Cracking in the stir zones of Mg-alloy friction stir spot welds, Journal of Materials Science, 42, 18, 7657–7666, 2007. https://doi.org/10.1007/s10853-007-1662-2.
T. J. Luo, B. L. Shi, Q. Q. Duan, J. W. Fu and Y. S. Yang, Fatigue behavior of friction stir spot welded AZ31 Mg alloy sheet joints. Transactions of Nonferrous Metals Society of China, 23, 7, 1949–1956, 2013. https://doi.org/10.1016/S1003-6326(13)62682-5.
F. Dahmene, S. Yaacoubi, M. E. Mountassir, G. Porot, M. Masmoudi, P. Nennig, U. F. H. Suhuddin and J. F. Santos, Dataset from healthy and defective spot welds in refill friction stir spot welding using acoustic emission. Data in Brief, 45, 108750, 2022. https://doi.org/10.1016/j.dib.2022.108750.
K. Zhang, Z. Zhou and J. Zhou, Application of laser ultrasonic method for on-line monitoring of friction stir spot welding process, Applied Optics, 54, 25, 7483, 2015. https://doi.org/10.1364/ao.54.007483.
Z. Zhou and K. Zhang, Evaluation of friction stir spot welding process by laser ultrasonic method with synthetic aperture focusing technique. 19th World Conference on Non-Destructive Testing, Munich, Germany, 13-17 June 2016.