Structural response of superaustenitic stainless steel to friction stir welding

Electron backscattering diffraction was employed to study grain structure development and texture evolution during friction stir welding (FSW) of a low stacking fault energy material, S31254 superaustenitic stainless steel. Formation of the final stir zone (SZ) microstructure was deduced to be primarily governed by discontinuous recrystallization occurring during the FSW cooling cycle. The textural pattern formed in the SZ was interpreted in the terms of {1 1 1}〈u v w〉 and {h k l}〈1 1 0〉 partial simple shear fiber textures.

► Grain structure evolution was mainly governed by discontinuous recrystallization.
► The recrystallization was static in nature and occurred during weld cooling cycle.
► Material flow was mainly induced by the tool shoulder.
► The texture was a superposition of {1 1 1} 〈u v w〉 and {h k l} 〈1 1 0〉 partial simple-shear fibers.