Forthefirst time,asystematicstudyoftheinfluenceoftoolgeometryonthe frictionstirwelding(FSW)processofInconel700throughresponsesurface methodology(RSM)formodelingpurposeswasinvestigated.Thetooldesign implemented twodistinct pinprobegeometries: a threadedpinwith three intermittent flat faces (D1) anda fully threadedcylindrical pin (D2). The presentstudyprimarilyexaminestheeffectsof thesevaryingpingeometries on FSWperformance in Inconel 700 joints. Additionally, experimental analyses, i.e., Vickers hardness number (VHN), ultimate tensile strength (UTS), and surface roughness (SR), were conducted to evaluate key mechanical properties. The response surface methodology (RSM) was evaluatedas asuitableapproachfor determining theweldproperties,with mathematicalmodelsachievingconfidencelevelsof93%and98%fortheD1 andD2 tool configurations, respectively.Meanwhile, theD1pingeometry