Galvanized cables are wire ropes that have undergone a metallurgical process known as galvanizing to increase corrosion resistance, durability, and temperature resistance. Individual wires, strands, or the cable as a whole may be treated with zinc for improved product features and longevity. The process enhances both the internal properties of the underlying steel and creates a protective exterior layer.
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Applications of Galvanized Cables
Galvanized steel cables are popular in applications where extreme atmospheric conditions such as temperature and precipitation may otherwise decrease the functionality of wire ropes. Construction, aeronautics, mining, marine, utilities, communications, automotive, and many other industries frequently use galvanized cable in support and control features. Stainless steel cables are also popular in these applications, though galvanized cables are an economic alternative that boast similar properties and features in less caustic environments.
Galvanized Cable Design and Manufacturing Process
Along with wire rope fittings and other connectors, galvanized cables are composed of three basic parts. Wires are often cold drawn metal filaments of a relatively small diameter. Two or more of these are braided or twisted into a grouping known as a strand which in turn is helically wrapped around a core. Galvanization is often a post-forming process, but can be performed on wires, strands, or completed ropes. The traditional method for galvanizing wire rope is known as hot-dip galvanizing or hot-dipping. Cables, or components, are first cleaned with a light acidic solution before being fed or submerged into a molten zinc bath, heated to around 860°F. The zinc chemically reacts with the iron or steel, forming a permanent bond with the substrate. When removed from the bath and subsequently exposed to atmospheric oxygen and carbon dioxide, the zinc is cured and forms a protective layer of zinc carbonate. Electrolytic-galvanizing may also be used for a thinner, more tightly bonded coating made possible by passing an electric current through the zinc compound. Additional methods include coating the cable with an organic solvent that evaporates while the zinc reacts, as well as coating the cable with zinc powder before processing in a rotary oven. Depending upon the method and specific requirements of a given application, steel cables can be coated with one or more layers of zinc in order to improve strength and corrosion resistance. Thickness of these layers most often ranges between one mil and just over four mils.
Factors to Consider When Purchasing Galvanized Cables
It is important to take environmental and mechanical stresses into account when selecting the proper galvanized cable. Further considerations include the overall size and diameter, breaking strength, design and ductility. Some uses for galvanized cable may also require the use of fittings, fasteners or other hardware which allow for connectivity and may prevent fraying of the rope. These components may or may not be galvanized dependent upon the requirements of their intended use.
Advantages of Using Galvanized Cables
Galvanized cables offer several advantages over non-coated cables, such as:
- Low Cost
- The process of galvanization does not have to involve pricey materials. It is cheaper to apply galvanization on steel than any other material. Additionally, the process does not entail the involvement of multiple workers. Furthermore, due to increased durability, the overall cost of using zinc-coated wire ropes is very low compared to alternative methods.
- Low Maintenance
- Zinc coating protects wire against corrosion. The coating layer protects the wire from a number of pollutants. These pollutants can potentially affect the endurance of the wire. Generally, galvanized wires do not easily break, do not need frequent repairs, and perform efficiently in a variety of applications. Galvanized wires are also tiny in size and can be used in remote locations that are not easy to access. Low maintenance also results in low operational cost.
- Highly Reliable
- The U.S. government has set certain guidelines for businesses that produce and use galvanized wire—they are strictly required to follow these rules. Manufacturers of galvanized wires have to ensure that they are applying a standard thickness of coating, ensuring reliability of the finished product.
- Added Robustness
- Galvanized coating adds to the strength of a cable. The coating’s metallurgical structure ensures that the coated cable can perform well in virtually any application.
- Damage Reduction
- After galvanization, the zinc coating provides automatic protection to areas of the wire that are exposed due to damage. However, such use is limited to small areas only.
- Complete Protection
- Galvanization also provides coated wires complete protection against deterioration. The toughness that this coating brings to an application is unmatched.
- Improved Maintenance
- Galvanized wires are easy to maintain. You can also apply non-destructive testing methods to assess the condition of the coated wires.