Aluminium alloy AlMg4.5Mn has got comprehensive acceptance in the manufacturing of light weight frames, marine structures which require high strength and worthy corrosion revulsion. The present investigation work focuses on friction stir welding process in which influences of operating parameters have been studied on friction stir welded butt joints. The FSWed joints specimens have been produced by experimentation at three levels of tool traverse speed and tool rotational speed keeping input force and tool tilt angle constant. Mechanical properties and microstructure of welded joints have been investigated in the present study. Change in the microstructure at different zones which transforms the mechanical properties of welded joints was due to the asymmetrical flow of material and thermal cycles around the pin. The second phase beta grains are formed as the very high temperature reached due to input parameters combinations. Traverse speed (TS) and tool rotational speed (TRS) are taken in a range of 16-40 mm/min and 500-1400 rpm, respectively. The best combination of parameters results in higher tensile strength which is well supported by the micro-hardness curve and the compact grains microstructure profile. Microstructure at different points and physical properties exhibited by the welded joint are well brought into line to summarize the effects of different parameters.

In the present experimental study, two dissimilar sister aluminum alloys, 5083 and 5086, are welded through friction stir welding process. Different experiments are conducted on vertical milling machine through a fixture design and firm holding welding plates on it. These experiments are performed by varying welding parameters including welding speed, rpm, different pin profiles, tool tilt angle at five levels each. Two different mechanical properties of the welded specimen (i.e. tensile strength and percentage of elongation) have been tested and compared with the base metals to find out the joint efficiency. Also it is observed that rpm, tool tilt angle and different pin profiles make significant impacts on friction stir welded joints. Tool rpm increases the tensile strength to an extent. Also, tool pin profile affects the stirring or plastic flow of material under tool shoulder. It is shown through visual and optical analysis that surface finish and weld quality of joints depend on tool tilt angle.