Marine corrosion of selected small wire ropes and strands

The breakage loads of nine different small mooring lines are experimentally related to time of immersion in a marine environment. Samples of a single steel wire, five different strands ranging from 0.05 inch 1 × 7 to 7/64 inch 1 × 19, and three small wire ropes 3/32 inch 7 × 7 were fully immersed in Puget Sound for 38, 115, and 150 days. Tensile test data from the immersed samples are analyzed and compared with data from control samples. The time rate of change of breakage load during approximately 6 months of exposure is given for bare lubricated steel wire and strand, galvanized steel strand, aluminized rope, and PVC coated wire rope. Results indicate that the rate of corrosion damage of bare lubricated steel wires and strands decreases from a high initial value to a lower constant value. An expression in terms of time, initial wire radius and a pseudo corrosion rate for the corrosion damage (as measured by breakage load) is developed on the assumption that the lost area can be modeled as an annulus.