Galvanized steel wire rope

Steel wire ropes with different amounts of zinc coating (galvanizing) and different types of construction were exposed in Pacific Ocean seawater at depth to determine their corrosion behavior. Some were stressed in tension to determine their susceptibility to stress corrosion or whether stress increased their rates of corrosion. The corrosion behavior of these galvanized steel wire ropes is given in Table 3.24. 

Table 3.24 Corrosion of Galvanized Steel Wire Ropes in Pacific Ocean Seawater Exposed at Various Depths for up to 3 Years W SJ 00... 

The life of rope made from galvanized steel wires is, however, greater than that of the individual wires (Schikorr, 1943-1944 ASTM, 1956). Schi-korr explains this by pointing out that the parts of the wire that lie on the outside are corroded more rapidly and, when the zinc film is penetrated in... 

Schikorr, G. (1943/1944). Die Witterungsbestandigkeit verzinkter Stahldahte und Drahtseile (The behavior of galvanized steel wire and wire rope). Arch. Eisen-huttenwes., 17, 147-150 (in German). 

Galvanized wire guy strand shall conform to ASTM A-475 Zinc-Coated Steel Wire Strand. Aluminized wire guy strand shall conform to ASTM A-474 Aluminum Coated Steel Wire Strand. Galvanized structural strand shall conform to ASTM A-586 Zinc-Coated Steel Structural Strand. Galvanized structural rope shall conform to ASTM A-603 Zinc-Coated Steel Structural Wire Rope. ... 

Reinhart (1976) has reported on the use of zinc alloys and zinc wire ropes that were exposed in the Pacific Ocean at depths of 720-2070 m for periods varying from 123 to 1064 days. The zinc alloy composition was 99.9% zinc, 0.9% lead, and 0.1% iron. The wire ropes were galvanized steel cables of various types. The data obtained from the study are given in Tables 3.23 and 3.24. From the data shown in Table 3.23, the corrosion rate of zinc in Pacific Ocean seawater is seen to decrease with the duration of exposure, except for zinc at the 2400 ft depth, at which the corrosion rate increased with increasing time of exposure. Also, the corrosion of zinc was greater at depth than at the surface. In addition, the report indicated that the corrosion of zinc was not uniformly influenced by changes in the concentration of oxygen in seawater between the limits of 0.4-5.75 mL/L. 

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