Armco Nitronic 60 (trademark of Armco Inc.) austenitic stainless, supplied in 76.2-mm-diameter annealed round bar, was tested for fretting behavior in its “as-received” and “solution heat treated” conditions. In the “as-received” condition, the microstructure showed a profusion of precipitates (nitrides, carbides, and carbonitrides), in the main, confined to grain boundaries. Solution heat treatment reduced the precipitate concentration but did not eliminate the second phase entirely. Fretting was carried out both in artificial seawater and 0.1 M H 2SO 4 to show the comparative effects of solution type. In artificial seawater, the form of scars in both “as-received” and “solution heat-treated” conditions, and the friction behavior, were broadly similar, reflecting the influence of solid precipitates, forming from the electrolyte outside the scar, becoming compacted back into the scar as fretting proceeds. In 0.1 M H 2SO 4, the absence of solid precipitate outside, and the continuous disruption of a passive oxide film inside the scar, gives rise to a different form of corrosion, i.e., severe crystallographic etching and intergranular attack. Friction results are unique under these conditions. Solution heat treatment only marginally improved the condition.