Variation of Tool Offsets and Its Influence on Mechanical Properties of Dissimilar Friction Stir Welding of Aluminum All

The tool offset parameter’s influence on joint strength of friction stir welding (FSW) of aluminum alloy 6061 and S235JR steel performed on a conventional belting milling machine was evaluated. The type of welding defects that arose at different tool offs

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Abstract The tool offset parameter’s influence on joint strength of friction stir welding (FSW) of aluminum alloy 6061 and S235JR steel performed on a conventional belting milling machine was evaluated. The type of welding defects that arose at different tool offset values and how they affect the ultimate tensile strength (UTS) of the joints produced are also studied. It was found that at +0.2 and 0 mm offset, welding was incomplete and tunnel defects were formed, with average tensile strengths of 22.91 and 41.62 MPa for joints welded at each tool offset values respectively. Tool offset value of −0.2 mm was found to produce the best joints in terms of tensile strength, at an average of 95.73 MPa. For all joints, in terms of defects it was found that incomplete welding severely reduced tensile strength of joints, while tunnel defects also deteriorated tensile strength of joints albeit to a lesser degree.

1 Introduction Friction stir welding (FSW) is a welding technique that was first introduced by The Welding Institute (TWI), London in 1991 [1]. Its solid-state nature means it offers a few improvements over other conventional welding techniques, the most notable one being the reduction of heat input. Several solid-state bonding techniques have W.M. Syafiq (&)  M. Afendi  R. Daud School of Mechatronic Engineering, Pauh Putra Campus, Universiti Malaysia Perlis (UniMAP), 02600 Arau, Perlis, Malaysia e-mail: wmsyafi[email protected] M.N. Mazlee School of Materials Engineering, Centre of Excellence for Frontier Materials Research, Universiti Malaysia Perlis, 01000 Kangar, Perlis, Malaysia N.A. Jaafar Advanced Technology Training Center (ADTEC), Lot 635, Jln Mahang, 09500 Karangan, Kulim, Kedah, Malaysia © Springer Nature Singapore Pte Ltd. 2017 M. Awang (ed.), 2nd International Conference on Mechanical, Manufacturing and Process Plant Engineering, Lecture Notes in Mechanical Engineering, DOI 10.1007/978-981-10-4232-4_3

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gained interest because of this, such as ultrasonic joining, friction welding and diffusion bonding [2–4]. However, friction welding is limited because at least one-half of the joint must be circular. Diffusion welding is a long joining process, while ultrasonic welding is only applicable on thin plates. Compared to FSW, in addition to its solid-state nature it is also a relatively quick process and is able to weld different thicknesses and joint shapes such as lap joints and T-joints [5, 6]. Honda Motor Co. Ltd. incorporated FSW in their fabrication of the Accord 2013 and took advantage of the technique’s various perks to weld the front sub-frame of the model, subsequently making Honda the first company in the automotive industry to apply the technique in mass production [7]. One important consideration when welding hard materials like steel is tool durability, as the tool gets severely damaged due to friction with steel and the resulting high temperature. Kimapong et al. found that for FSW of AA5083 and SS400 steel, a tool that was offset 0.2 mm into the steel produced joints with t