In this work, the parameters, which have a large influence on the surface quality of Aluminum
alloy 6082-T61 welded joints when using (UAFSW) and (CFSW), are studied. These
parameters are; rotational speed (600-1200 rpm), welding speed (80-160 mm/min), and
amplitude (40-100 µm). The analysis of the welding process results for the ultrasonic assisted
friction stir welding (UAFSW) and the conventional (CFSW) methods show that the ultimate
tensile strength at low and medium welding speeds (80 and 120 mm/min) is generally high in
both two methods of welding, and it is increased by about 16% in UAFSW than the
conventionally (CFSW). The increase of the welding speed to 160 mm/min, leads to the
obvious increase in the surface roughness (Ra). The values of (Ra) are high at the beginning of
the welding span for all use of the rotational speeds and the welding speeds. But in the middle
distance of span, the improvement of the surface quality is clear, and at the end of the welding
operation, the values of (Ra) is increased but with small values of roughness as compared with
the values at the beginning of welding operation. The rotational speed of the tool is the
important factor that has a large influence on the resultant surface roughness (Ra) of the welded area of the joint and the increase in tool rotary speed decreases the surface roughness (Ra). The increase in US power decreases the surface roughness and gives better surface quality.