A Novel Technique for Keyhole-Less Reinforced Friction Stir Spot Welding of Polyethylene Sheets

Document Type: Original Article


1 Department of Mechanical Engineering, University of Birjand, Birjand, Iran

2 Department of Mechanical Engineering, University of Birjand, Iran


Two main problems exist with friction stir spot welded joints; remaining of a keyhole after welding and low strength of joints. In this paper, a novel method is proposed to address both problems in a simple and cost-effective way. This process is named “Reinforced Friction Stir Spot Welding” or “RFSSW” which is based on recently introduced “TFSSW” process. SiC powder was added to the friction stir spot joints of polyethylene sheets with a thickness of 3 mm. First, the sheets were welded using conventional friction stir spot welding tool with a cylindrical pin. Then, the keyhole was filled with SiC powder. In the second stage, for stirring of SiC particles in the nugget and refilling the keyhole as well, a pinless tool was utilized. A homogenized distribution of reinforcing powder was obtained in the nugget. The effect of welding parameters including refilling tool shoulder diameter, refilling dwell time, and refilling tool rotational speed were evaluated in both TFSSW and RFSSW. In both processes, the refilling tool shoulder diameter was the most effective parameter. The strength was increased by 40% applying TFSSW and a further increase by 20% was obtained by reinforcing. Optimized parameter levels are refilling tool shoulder diameter of 24 mm, refilling tool rotational speed of 800 rpm, and refilling dwell time of 50s which result in shear strength of 1079 N.


[1]     Sattari, S., Bisadi, H., and Sajed, M., Mechanical Properties and Temperature Distributions of Thin Friction Stir Welded Sheets of AA5083, International Journal of Mechanics and Applications, Vol. 2, No. 1, 2012, pp. 1-6, DOI. 10.5923/j.mechanics.20120201.01.

[2]     Reimann, M., Gartner, T., Suhuddin, U., Göbel, J., and dos Santos, J. F., Keyhole Closure Using Friction Spot Welding in Aluminum Alloy 6061–T6, Journal of Materials Processing Technology, Vol. 237, 2016, pp. 12-18, DOI. 10.1016/j.jmatprotec.2016.05.013.

[3]     Dong, H., Chen, S., Song, Y., Guo, X., Zhang, X., and Sun, Z., Refilled Friction Stir Spot Welding of Aluminum Alloy to Galvanized Steel Sheets, Materials & Design, Vol. 94, 2016, pp. 457-466, DOI. 10.1016/j.matdes.2016.01.066.

[4]     Uematsu, Y., Tokaji, K., Tozaki, Y., Kurita, T., and Murata, S., Effect of Re-Filling Probe Hole on Tensile Failure and Fatigue Behaviour of Friction Stir Spot Welded Joints in Al–Mg–Si Alloy, International Journal of Fatigue, Vol. 30, No. 10, 2008, pp. 1956-1966, DOI. 10.1016/j.ijfatigue.2008.01.006.

[5]     Dourandish, S., Mousavizade, S. M., Ezatpour, H. R., and Ebrahimi, G. R., Microstructure, Mechanical Properties and Failure Behaviour of Protrusion Friction Stir Spot Welded 2024 Aluminium Alloy Sheets, Science and Technology of Welding and Joining, Vol. 23, No. 4, 2017, pp. 1-13, DOI. 10.1080/13621718.2017.1386759.

[6]     Sajed, M., Parametric Study of Two-Stage Refilled Friction Stir Spot Welding, Journal of Manufacturing Processes, Vol. 24, No. 1, 2016, pp. 307-317, DOI. 10.1016/j.jmapro.2016.09.011.

[7]     Jeon, C. S., Jeong, Y. H., Hong, S. T., Tariqul Hasan, M., Tien, H. N., Hur, S. H., and Kwon, Y. J., Mechanical Properties of Graphite/Aluminum Metal Matrix Composite Joints by Friction Stir Spot Welding, Journal of Mechanical Science and Technology, Vol. 28, No. 2, 2014, pp. 499-504, DOI. 10.1007/s12206-013-1153-0.

[8]     Hong, S. T., Das, H., Oh, H. S., Nur-E-Alam-AlNasim, M., and Chun, D. M., Combination of Nano-Particle Deposition System and Friction Stir Spot Welding for Fabrication of Carbon/Aluminum Metal Matrix Composite Joints of Dissimilar Aluminum Alloys, CIRP Annals - Manufacturing Technology, Vol. 66, No. 1, 2017, pp. 261-264, DOI. 10.1016/j.cirp.2017.04.115.

[9]     Bilici, M. K., Yukler, A. I., Effects of Welding Parameters on Friction Stir Spot Welding of High Density Polyethylene Sheets, Materials & Design, Vol. 33, 2012, pp. 545-550, DOI. 10.1016/j.matdes.2011.04.062.

[10]  Bozkurt, Y., The Optimization of Friction Stir Welding Process Parameters to Achieve Maximum Tensile Strength in Polyethylene Sheets, Materials & Design, Vol. 35, 2012, pp. 440-445, DOI. 10.1016/j.matdes.2011.09.008.

[11]  Bilici, M. K., Yükler, A. İ., and Kurtulmuş, M., The Optimization of Welding Parameters for Friction Stir Spot Welding of High Density Polyethylene Sheets, Materials & Design, Vol. 32, No. 7, 2011, pp. 4074-4079, DOI. 10.1016/j.matdes.2011.03.014.

[12]  Bozkurt, Y., Bilici, M. K., Application of Taguchi Approach to Optimize of FSSW Parameters on Joint Properties of Dissimilar AA2024-T3 and AA5754-H22 Aluminum Alloys, Materials & Design, Vol. 51, 2013, pp. 513-521, DOI. 10.1016/j.matdes.2013.04.074.

[13]  Bilici, M. K., Application of Taguchi Approach to Optimize Friction Stir Spot Welding Parameters of Polypropylene, Materials & Design, Vol. 35, 2012, pp. 113-119, DOI. 10.1016/j.matdes.2011.08.033.

[14]  Rezaee Hajideh, M., Farahani, M., Alavi, S. A. D., and Molla Ramezani, N., Investigation on the effects of Tool Geometry on the Microstructure and the Mechanical Properties of Dissimilar Friction Stir Welded Polyethylene and Polypropylene Sheets, Journal of Manufacturing Processes, Vol. 26, 2017, pp. 269-279, DOI. 10.1016/j.jmapro.2017.02.018.

[15]  Aghajani Derazkola, H., Simchi, A., Experimental and Thermomechanical Analysis of Friction Stir Welding of Poly (Methyl Methacrylate) Sheets, Journal of Manufacturing Processes, Vol. 34, 2018, pp. 412-423, DOI. 10.1016/j.jmapro.2018.06.015.

[16]  Khodabakhshi, F., Haghshenas, M., and Chen, J., Bonding Mechanism and Interface Characterisation During Dissimilar Friction Stir Welding of an Aluminium/Polymer Bi-Material Joint, Science and Technology of Welding and Joining, Vol. 22, No. 3, 2017, pp. 182-190, DOI. 10.1080/13621718.2016.1211583.

[17]  Singh, R., Kumar, V., Feo, L., and Feraternali, F., Experimental Investigations for Mechanical and Metallurgical Properties of Friction Stir Welded Recycled Dissimilar Polymer Materials with Metal Powder Reinforcement, Composites Part B: Engineering. Vol. 103, 2016, pp. 90-97, DOI. 10.1016/j.compositesb.2016.08.005.

[18]  Gao, J., Li, C., Shilpakar, U., and Shen, Y., Improvements of Mechanical Properties in Dissimilar Joints of HDPE and ABS via Carbon Nanotubes During Friction Stir Welding Process, Materials & Design, Vol. 86, 2015, pp. 289-296, DOI. 10.1016/j.matdes.2015.07.095.

[19]  Sajed, M., Bisadi, H., Experimental Failure Study of Friction Stir Spot Welded Similar and Dissimilar Aluminum Alloys, Welding in the World, Vol. 60, No. 1, 2016, pp. 33-40, DOI. 10.1007/s40194-015-0268-6.