Friction stir processing of austenitic stainless steel cold spray coating deposited on 304L stainless steel substrate: feasibility study

In this work, the feasibility test of friction stir processing (FSP) 1.5-mm-thick austenitic stainless steel cold spray coating deposited on 304L substrate was performed using tungsten carbide tool. Applied FSP parameters (advance speed 50 mm/min, rotation 300 rpm, axial force 20 kN, tilt angle 1.5°) allowed to perform treatment with a higher depth than thickness. As result, material mixing at coating-substrate interface observed. The microstructure observation revealed that in zone significantly modified. EBSD analysis confirmed full recrystallization during formation dense and uniform fine-grained structure mean grain size 1.9 mm. Average microhardness decreased from 406 299 HV. Further parameter optimization should be carried out order improve process reliability avoid any failure treatment.