The unlubricated fretting wear of mild steel in air

Fretting experiments were carried out on mild steel in air to long sliding distances over a range of loads and stroke amplitudes. For peak-to-peak fretting amplitudes greater than 5 μm, three fretting stages were identified: an initial adhesive transfer stage, an intermediate stage where both metallic and oxide debris were produced and a terminal stage characterized by extensive oxide debris beds and continuing wear rates some 50 times smaller...