Investigation of mechanical and microstructural characteristics of friction stir spot welded joints of aluminum sheets

In this work, the principle of (Friction Stir Welding ,FSW) process used to produce spot welded lap joint aluminum sheets with (2.5 mm) thickness sheet different welding parameters. Different rotational speed have been selected show effect change, tool was (710, 900, 1400 RPM) same time (15 sec.). Another experiment conducted and (30 sec) time. Mechanical microstructural properties joints studied also. Results that; there is an optimum for maximum shear stress when all other parameters are constant .The results grain size in stirred zone smaller than that parent material which improve weld properties. Based on study obtained, welds can be produced using good mechanical sheets.