Experimental Analysis of Tool Rotational Speed Effect on Strength and Microstructure in Friction Stir Welding of (AA6061) Aluminium Alloy

Friction Stir Welding (FSW) is a popular solid-state joining technique, particularly useful for aluminum alloys because it avoids issues associated with melting during traditional welding. This research focuses on AA6061 aluminum alloy, a material commonly used in industries like aerospace, automotive, and marine. The primary goal is to understand how the speed at which the welding tool rotates affects the strength and internal structure of the FSW joints. Experiments were conducted by changing the tool's rotational speed while keeping other factors like travel speed, axial force, and tool angle constant. The joints were created using a Milling Machine with a specially shaped H13 steel tool and cold work die steel. The welded samples were then tested for tensile strength and hardness, and their internal structure was examined using optical microscopy to assess the quality of the joint. The results indicated that the tool's rotational speed has a considerable impact on heat creation, material movement, and grain size. An ideal rotational speed was found, resulting in the highest tensile strength and a consistent, fine-grained internal structure. This investigation offers important knowledge for optimizing FSW parameters to produce reliable and strong joints in AA6061 alloy.