Influence of tool pin profile on the mechanical strength and surface roughness of AA6061-T6 overlap joint friction stir welding

This study presents the tensile strength and surface roughness resulting from friction stir welding (FSW) on the lap joint method using AA 6061 –T6. FSW is conducted by comparing three different tool pin shapes: hexagon, thread, and square. Overlap welding using the FSW method is challenging if machine parameters, such as spindle speed and feed rate, are incompatible. The experiment was conducted using a conventional milling machine with a spindle speed of 1400 -1750 rpm and a feed rate of 20 – 30 mm/min. The results show that a spindle speed of 1750 rpm and a feed rate of 30 mm/min using a square tool pin results in 83.5088 MPa ultimate tensile strength and 0.85 µm surface roughness (Ra), which is much better than hexagon and thread type tool pins. In addition, the overall results on all three tool pin shapes show that higher processing parameters increase tensile strength and surface roughness. This study revealed the effect of parameters on AA6061 –T6 and the resulting implications of mechanical strength and surface roughness.