Influence of friction stir welding parameters on metallurgical of AA6061-T651 aluminum alloys

This study aims to determine the effect of variations in process parameters on the aluminum microstructure of FSW AA6061-T651 using a butt joint with a hexagonal pin geometric tool. Aluminum alloy AA6061-T651 has a melting point of 600oC and is widely used for the manufacture of trains, ships, aircraft, and others. Friction Stir Welding (FSW) is the latest innovation in solid-state welding suitable for low melting point aluminum. The FSW process uses the Taguchi Orthogonal Array experimental design method to study all FSW parameters and minimize the experiments carried out. In this study, the process parameters used were tool rotation speed 765, 1208, 1907, 3022 (rpm), welding speed 24, 43, 65, 90 (mm/min), tool tilt angle 2, 2.5, 3, 3.5 (deg.), and a concave shoulder angle of 2, 5, 8, 11 (deg.). Microstructural testing in this study used the ASTM e407-07 standard. The results of this study indicate that the weld metal has an equiaxed structure and has Al, AlFeSi, and Mg2Si phases. The results of FSW with a tool inclination of 2 degrees found in specimens 1, 6, 11, and 16 have the best microstructural results because they have more Mg2Si phases, thereby changing their mechanical properties for the better. The results of microstructure testing on specimen 5 have the worst microstructural results because they have the lowest hardness values. The results of the microstructure test on the test object 15 had the best microstructure results because it had the highest hardness value.