On friction stir welding of a medium manganese austenitic steel

The plates of an Fe–12%Mn–0.5%C–1.5%Al austenitic steel with an original grain size of 80 µm were subjected to friction stir welding using a spherical welding pin. The fine grained microstructures with a grain size being dependent on the welding feed speed were evolved in the stir zones. The microstructure evolution in the stir zone resulted from a kind of post-dynamic recrystallisation. An increase in the welding pin motion along the seam...