Improving Weld Joint Quality Using Friction Stir Welding Technique

The use of friction stir welding (FSW) in welding ASTM A536 Grade 60-40-18 cast iron was carried out in this research work. This was with a view to ascertain and improve the quality of the welded joint produced using FSW when compared with other conventional welding processes like tungsten inert gas welding (TIG) and manual metal arc welding (MMA). Taguchi method for design of   was adopted to determine the effects of the various process parameters such as welding speed, travel speed and tilt angle on the quality of the welded joints produced. There was the need to select FSW parameters that give the optimum quality of welded joints. Results obtained indicate that better hardness and impact strength values were obtained when FSW was used in welding cast iron than the conventional welding processes such as Tungsten inert gas (TIG) and metal inert gas (MIG). The hardness of FSW obtained was 175HRB and those of TIG weld and MIG welded joints were 102HRB and 90HRB, respectively. It was also observed that the ultimate tensile strength of FSW is slightly lesser than that of TIG welded joint with a percentage deviation of 3.49%. Generally, the results of
non-destructive test (NDT) carried out on all the welded
joints indicate good visual and magnetic particle test results
with the absence of porosity and surface cracks.