A systematic approach was presented to discuss the modeling of tool geometry effects on the
friction stir 6061 aluminum pipes welds using response surface methodology(RSM). The tool
design with the different pin probe geometries tool designing was made for two pins of tools, based
on two types of probes such as conical Pin, and triangular Pin. Then, the influences of pin
geometries on friction stirred aluminum welds were experimentally scrutinized with respect to
hardness(HVN) , tensile strength(UTS) and surfaces roughness(Ra) in order to demonstrate the
feasibility of friction stir welding for joining Al 6061 aluminum alloy welding was performed on
pipe with different axial force 1 ,1.5 and 2 KN, rotational speeds 1000,1400 and1800 rpm and a
traverse speed 4 ,8 and10 mm/min was applied, The response surface methodology was found to
be appropriate for locate the FS weldment properties. The developed mathematical model can be
used effectively at 98% and 99% confidence level D1( conical pin) and level D2(triangular pin).
The result conical pin profile is better than the triangular pin profile because the obtained hardness
values are higher for friction stir welded joint. The surfaces roughness created by FSW of conical
profile tool better than triangular pin profile