Microstructure, texture and mechanical properties of a nickel-free high nitrogen duplex stainless steel processed through friction stir spot welding

A nickel-free high nitrogen duplex stainless steel holding Mn-content was friction stir spot welded under the various rotational speeds. The microstructure/texture evolutions of joints and correlated mechanical properties were investigated in detail. ferrite austenite constituent massive phases refined down to mean grain size 0.9 μm 1.1 μm, respectively. microstructure revealed activation continuous dynamic recrystallization as main restoration mechanism. This further verified through formation Β- Α-fiber shear texture specimens processed processing condition. Besides different micro-mechanisms both austenite, phase transformation also contributed refinement. facilitated by providing more diffusional paths substructure development local bulk assessed. outstanding tensile-shear peak load 12.8 KN obtained for sample at 400 rpm discussed relying on developed ultrafine-grained maximum extension 1.7 mm achieved 600 attributed role strain accommodation.