If you work with wire rope, you probably know how important it is to limit the effects of corrosion. Proper corrosion resistance techniques will help you increase the longevity of any piece of wire rope. It is vital to have a strong grasp on the definition of corrosion itself. Corrosion is defined as the gradual degradation of a material due to exposure to natural chemical reactions that occur within a given environment. Atmospheric oxygen slowly corrodes materials over time, but certain environmental catalysts can expedite this process. For example, salt water is a catalyst that causes metals, such as steel, to corrode much faster than normal. Steel located near a source of salt water will degrade much quicker than a piece of steel that is inland.
In order to limit the ill effects of corrosion, most wire ropes are galvanized. In the past, Galvanization was a process of hot-dipping steel into liquidized zinc. The zinc adheres to the steel and creates a protective barrier against environmental catalysts.
This process slows down the occurrence of corrosion and significantly increases the longevity and durability of the wire rope but would decrease the strength compared to non-galvanized. In the past 20 years manufacturers have developed a technique called Drawn Galvanized. This process allows the manufacturers to get the strength of EIP Bright ropes, but this technique isn’t sufficient enough to keep corrosion at bay.
The best corrosion resistant wire rope is Stainless Steel. In the initial manufacturing process, steel is combined with nickel and chromium to create a stainless steel alloy; the higher the nickel content, the less likely the steel is to corrode. On the down side, the higher the percentage of nickel, the weaker the steel alloy becomes. There are numerous grades of stainless steel on the market that mitigates this problem and helps to provide a wide array of options, with an intricate balance of strength and corrosion resistance.
When steel is paired with chromium, the chromium reacts with oxygen and creates a thin passivation layer over the metal. This layer is impenetrable by air or water, which quickly prevents the likelihood of corrosion of anything located below the layer.
For wire rope applications that are situated in harsh elements, it is best to use a stainless steel variation with high chromium content. But galvanized wire rope will be suitable for any wire rope that will be used in a controlled environment,