Abstract
Steel wire ropes widely used in the marine environment are subjected to aggressive species of corrosive attack. The surface of the steel wire ropes is usually protected by galvanizing. The thickness of the zinc coating depends on the class of galvanizing. Case studies presented will illustrate how service life can be influenced by the local conditions including the type of zinc coating. This paper presents typical corrosion failure analysis investigations performed on steel wire ropes used in the marine industry of Trinidad and Tobago. Case study 1 shows the stranded wire rope attached to a mooring buoy located at a remote location in the ocean. The wire rope failed approximately one year after installation at a point at the base of the socket. Case study 2 showed a spiral strand steel wire rope installed on a Link belt crane located in a marine environment. The rope also failed after one year in service. The analysis performed on the failed components comprised a number of analytical techniques and testing methods that resulted in the determination of the root cause of failure being a lack of lubrication that eventually caused coating damage, peening, embrittlement, inter-strand nicking and fretting wear of the wire ropes. Recommendations were suggested to prevent the occurrence.
