The Effect of Pin Profiles and Process Parameters on Temperature and Tensile Strength in Friction Stir Welding of AL6061 Alloy S. Emamian, M. Awang, F. Yusof, Patthi Hussain, Bahman Meyghani and Adeel Zafar Abstract The main source of the heat generation during the Friction Stir Welding (FSW) is the friction force between tool and workpiece and the plastic deformation. The geometry of the tool including the pin and the shoulder highly affects the friction force. In this study, the effects of different pin profiles with different rotational and traversing speed are evaluated in order to obtain the optimum pin profile using heat generation and tensile strength. Three different rotational speed and welding speeds are applied with threaded cylindrical, conical, stepped conical and square pin pro- files. Thermocouples K type have been embedded in order to record the temperature during the welding at the advancing and the retreating side. Moreover, tensile test and microstructure analysis are performed in order to study the microstructure. The results of experimental process and design of experiments are correlated well. The better joint produced with threaded cylindrical tool pin profile with rotation speed of 1600 rpm and welding speed of 40 mm/min. Keywords FSW · Pin profile · Friction stir welding · Heat generation · Tensile strength 1 Introduction Friction Stir Welding (FSW) was invented and patented by Thomas et al. at The Welding Institute (TWI) [1, 2]. There are three stages in the process plunging; welding stage and plunging out step. In the plunge stage, FSW tool which is made up of a pin and a shoulder, penetrates the plates. In some cases, there is a dwell time in which S. Emamian · M. Awang (B ) · P. Hussain · B. Meyghani · A. Zafar Department of Mechanical Engineering, Universiti Teknologi PETRONAS, Bandar Seri Iskandar, Malaysia e-mail: mokhtar_awang@utp.edu.my F. Yusof Department of Mechanical and Manufacturing, University of Malaya, Kuala Lumpur, Malaysia © Springer Nature Singapore Pte Ltd. 2019 M. Awang (ed.), The Advances in Joining Technology, Lecture Notes in Mechanical Engineering, https://doi.org/10.1007/978-981-10-9041-7_2 15