Electropolishing study of metastable austenitic steel AISI 347 for EBSD analyses

Abstract For the metastable austenitic steel AISI 347 (X6CrNiNb18-10), various electropolishing parameters were evaluated by means of hardness testing, electron backscatter diffraction (EBSD), and atomic force microscopy. Depending on the chosen parameters, different surface characteristics could be achieved simply by only varying voltage, flow rate, and polishing time, although EBSD indexing was always possible. Differences in hardness of up to 20 HV0.5 and in microscopic roughness could be detected on otherwise comparable samples. Finally, the microstructure distribution of a hot rolled bar material with a diameter of 153 mm made from AISI 347 was characterized over the cross section using the previously determined parameter set. Here, insights about recrystallization during forming were concluded and δ-ferrite was differentiated from α’-martensite by kernel average misorientation and morphology.