Optimization of Welding Condition for Nonlinear Friction Stir Welding

Theinfluenceofnonlinearfrictionstirwelding(FSW)toolcontrolonjointpropertieswasinvestigated.AlthoughFSWiswidelyappliedtolinear joints, it is impossible for five-axis FSW machines to maintain all FSW parameters in optimum conditions during nonlinear welding.Nonlinear FSW joints should be produced according to an order of priority for FSW parameters. Tensile test results of butt joints withrectangularchangeintheweldingdirection ontheplateplane(L-shapebuttjoints)changewithvariousweldingparameters.Resultsshowthataturntotheretreatingsideisencouragedwhentheweldingdirectionchanges.Themethodofzeroinclinationtoolanglesiseffectivefornonlinearand plane welding. [doi:10.2320/matertrans.L-MRA2008807](Received January 4, 2008; Accepted February 28, 2008; Published April 16, 2008)Keywords: friction stir welding, nonlinear welding, aluminum alloy, microstructure, mechanical properties