Investigation of the effect of tool geometry on friction stir welding of 5083-O aluminum alloy

In this paper, effect of pin position (relative to tool shoulder position) on welded joint in friction stir welding (FSW) of aluminum 5083-O was investigated. FSW is a new solid-state welding process used to join metals and alloys (especially unweldable aluminums). To do this study, a FSW process was prepared by designing and fabricating tool and workpiece fixture and installing them on a milling machine. Then, some experiments were performed using the tool with a pin coaxial with the axis of tool shoulder. Hence, the tool enters edges of joint location and moves along joint line. Achieved results showed heat generation, severe plastic deformation, and material displacement in joint location which led to completeness of joint’s edges. It was also found that the tool temperature for tools with half pin and arched pin had a significant increase with the increase of rotational speed. Tools with more ability of mixing materials and forging of transferred material from the front of the pin to its back showed more ultimate tensile strength.