FRETTING DAMAGE IN LOCKED COIL STEEL ROPES

Locked coil steel ropes are used for high duty applications in aggress ive environments, such as those encountered in the mining industry. Th e service life of this class of rope can be variable. This paper exami nes the design features of the rope, and the operating regime, which m ay contribute to this variability in service life. These ropes are con structed from cold drawn eutectoid and hypo-eutectoid steel wires. A r ope is examined after a period in service close to its design life. Of the degradation mechanisms considered, fretting is found to produce s ignificant wear at points of contact between the layers of the rope, n ear its outer surface. Initiation of fretting wear is encouraged by th e breakdown of the added lubricant and the magnitude of the contact st resses. Two further papers will examine the fretting behaviour of a ty pical eutectoid steel wire used in this class of rope. In the first of these papers the residual lubricant coating from the wire manufacturi ng process is identified as playing an important role in the fretting behaviour. The second paper covers the influence of low viscosity oils , and solid additives, on the fretting behaviour.