Available online at www.sciencedirect.com ScienceDirect Materials Today: Proceedings 5 (2018) 4175–4182 www.materialstoday.com/proceedings 2214-7853 © 2017 Elsevier Ltd. All rights reserved. Selection and/or Peer-review under responsibility of 7th International Conference of Materials Processing and Characterization. ICMPC 2017 Effect Of Different Tool Pin Profiles On The Joint Quality Of Friction Stir Welded AA 6063 Mohd Azmal Hussain a *, Noor Zaman Khan b , Arshad Noor Siddiquee b , Zahid Akhtar Khan b a Department of Mechanical Engineering, Noida Institute of Engineering and Technology, Greater Noida, U.P, India b Department of Mechnaical Enginenring, Jamia Millia Islamia, New Delhi, India Abstract In the present paper an attempt has been made to investigate the effect of different tool pin profiles on the joint quality in terms of tensile strength during Friction stir welding (FSW) of 6063 aluminium alloy. 4.75 mm thick plates of AA6063-T6 were welded using FSW. Five different pin profiled tools of hot die steel were employed. Results of the study revealed that tapered cylindrical tool pin profile exhibited maximum tensile strength. Also, formation of tunnelling defect in the welded joint was discussed and recommendations of elimination/minimization of this defect were made. © 2017 Elsevier Ltd. All rights reserved. Selection and/or Peer-review under responsibility of 7th International Conference of Materials Processing and Characterization. Keywords: Tool pin profile; FSW; Tensile strength; Tunneling defect; AA 6063 1. Introduction Friction stir welding (FSW) is a new entry into the arena of solid state joining processes, which have been showing a lot of potential in welding technology. FSW was developed in 1991 [1] and as the temperature during the welding process is lower than the melting point of the respective work-piece thus it is fundamentally a solid state welding process [2], widely used for the welding of light and difficult-to-weld metals and their alloys like aluminium, * Corresponding author. Tel.: +91-11-26981259; E-mail address: ajmal0201@gmail.com