Design Metallurgist, NEI Parsons Ltd., Meaton Works, Newcastle Upon Tyne,
Senior Lecturer, School of Technology, Sunderland Polytechnic, Sunderland,
Pages: 12 Published: Jan 1992
An experimental assembly has been developed to enable aqueous fretting fatigue tests to be performed with an orthogonally crossed cylinder arrangement of fatigue specimen and fretting pad. The equipment has been employed in a study of the fretting fatigue behavior of the high strength, low alloy steel, Corten A, in both air and synthetic seawater environments.
The use of impressed cathodic protection has identified electrochemical dissolution processes as having a significant influence on fatigue life. Normal corrosion fatigue in seawater produces a 60% reduction in fatigue life compared to that in air, while the imposition of fretting causes a further 24% reduction in fatigue life.
The initiation sites of fretting fatigue cracks occur at the boundary between slip and non-slip regions in both air and aqueous environments. Cracks propagate at an oblique angle to the surface of the fatigue specimen. On leaving the zone of influence set up by the alternating shear stress, the cracks propagate perpendicular to the applied cyclic stress.
fretting corrosion, fretting fatigue, seawater corrosion, high strength steel, cathodic protection
Paper ID: STP25838S