OPTIMIZATION OF FRICTION STIR SPOT WELDING PARAMETERS OF DISSIMILAR WELDED JOINTS OF ALUMINUM ALLOY (AA2024T3) WITH PURE COPPER SHEETS

Friction stir spot welding (FSSW) was performed for welding of an aluminum alloy AA2024T3 sheet to commercial pure copper sheet of 2mm thick. Friction stir spot welding are carried out at different tool rotational speeds( 800,1000 &1250 ) rpm ,plunging ti mes (30 ,60 &90) sec and tool pin profile or geometry ( Threaded cylindrical with flute, Tapered cylindrical and straight cylindrical). Process parameters were optimized by using Taguchi technique and depending on design of experiment (DOE). The aluminum a lloy sheet was overlapped on the copper sheet . It was found that maximum shear force was (1527 N) obtained at optimum welding parameters : 1250 rpm rotation speed ,90 sec plunging time and straight cylindrical pin profile which are obtained from the ana lysis of response optimizer. Pareto chart the standardized effects of tensile shear results showed that the plunging time was the most effect parameter than other welding parameters( rotation speed and pin profile). From temperatures distributions measure ments in three points in nugget zone of spot weld , base aluminum alloy(AA2024T3) and base pure copper, it was found that maximum measured temperature was 383 C? in nugget zone of weld