Effect of pin shape and rotational speed on the mechanical behaviour and microstructures of friction stir spot welding of Aa6061 aluminum alloy

Abstract EN

Friction stir spot welding (FSSW) is a modern solid-state joining process able to weld similar and dissimilar overlap joints in different classes of materials and is widely being considered for automotive industry.

In this work, the mechanical behavior ) i.e.

tensile shear tests, Microhardness(, and microstructure of friction stir spot welded joints were studied for AA6061-T6 aluminum alloy sheets with thickness of 1.6 mm.

Series of FSSW experiments were conducted using vertical CNC milling machine type "C-tek".

FSSW is carried out at different pin profiles (cylindrical, taper, and triangular) and tool rotational typically speeds, i.e.

800, 1000, 1200 and 1400 rpm.

Based on the welding experiments conducted in this study, the results show that sheets welded by triangular pin tool have highest tensile shear load, of 3.2 kN, followed by welds with cylindrical pin, while welds made using taper pin has the tensile shear load 2.1 kN at optimum speed of 1200 rpm.

Also the pin shape and rotational speed had an obvious effect on microstructural parameters i.e.

hook height and bond width