Wire rope consists of multiple strands of wire filament which themselves are twisted together before being wound helically around a core. First used for mining in Germany during the mid 1800's, wire rope has become a staple in heavy industrial processes such as mining, oil rigging, bridge construction, marine applications and others that require various heavy-duty lifting and support applications such as cable railings.
As a versatile, high load capacity alternative to natural fiber ropes such as hemp and manila, wire rope provides motion transmission through nearly all angles, tie down, counterbalance, guidance, control or lift. Also referred to as stranded wire due to their multiple strand configuration, nearly all wire ropes, or cables, including control cables, are fabricated from strands of cold drawn carbon steel wires, although stainless steel cables are manufactured for highly corrosive environments. Galvanized cables are also popular for the increased strength and durability needed for specialized ropes such as aircraft cables. Specially treated steel cable and plastic coated cables are common to many application specific variations of wire robe such as push pull cable assemblies used in transferring motion between two points. Wire rope assemblies such as these are configurations of one or multiple ropes equipped with wire rope fittings for connecting to other cables, and wire rope slings or eye splices. Such applications extend the capabilities and applicability of wire ropes.
Obvious applications for wire rope include multi-ton hoisting and tie-down in industrial manufacturing, construction, ship rigging, oil rigging and mining, many other industries in the manufacturing and consumer sectors use wire rope. Additional applications abound, however, ranging from consumer goods to transportation. Fitness industries use plastic coated cable in most weight machines; theater industries use black powder coated cables for stage rigging; outdoor playground equipment often use plastic coated cables, and many types of electronic equipment, communications devices and medical devices use miniature wire rope and wire rope fittings. Each industrial, commercial or domestic application for wire rope requires the use of specialized cables best suited to that use. Suppliers typically identify wire cable by listing both the number of strands and the amount of wires per strand respectively, though stranded cable may alternatively be measured by their lay and length or pitch. Identification codes can also be extended to specifics which are abbreviated to quickly denote core type, work load limit and more. The connections, fasteners, fittings and other hardware are also listed by most suppliers as these offer differing degrees of versatility to a rope in terms of fray prevention and connectivity to anchors, equipment and other ropes.
While fittings and assemblies are important, there are three basic elements of which wire ropes are composed: wire filaments, strands and cores. The first components, filaments, are cold drawn rods of metal materials of varying, but relatively small diameter. Though steel is perhaps most common, several different metal wires are available including aluminum, nickel alloy, bronze, copper and titanium. A strand is formed when the individual wires are twisted or braided together. A single strand can consist of as few as two or as many as several dozen filaments and different gauges depending upon the strength, flexibility and wear resistance requirements. The core is an extremely versatile element of wire cables. This is the central element around which strands are wrapped and it may be composed of metal, fiber or impregnated fiber materials depending on the intended application. Cores may also be another strand of wire called an independent wire rope core (IWRC); wire rope cores maintain a considerable amount of flexibility while increasing strength by at least 7.5% over the strength of fiber core wire ropes. As important as each individual element is the manner in which they are combined. The helical winding of the strands around the core is known as the lay. Ropes may be right hand lay, twisting strands clockwise, or they may be left hand lay, twisting strands counter-clockwise. In and ordinary lay the individual strands are twisted in the opposite direction of the lay of the entire rope of strands to increase tension and to prevent the rope from coming unwound. Though this is most common Lang's lay has both the strands and the rope twisted in the same direction while alternate lays, as the name suggests alternate between ordinary and Lang style lays.
While alternative rope designs are available, the helical core design is often favored as it allows a wire cable to hold a lot of weight while remaining ductile. Even the heaviest industrial loads may be lifted with a well made wire rope because the weight is distributed evenly among constituent strands. The lay is crucial to this characteristic of wire ropes. As the cables play an integral role in the safety of many operations and structures, careful analysis of a wire rope and all of its capabilities and features is vital. Important qualities and physical specifications include diameter, breaking strength, resistance to corrosion, difficulty of flattening or crushing, ability to be bent, and average lifespan. Each of the aforementioned considerations should be compatible with the specific application for which the rope is intended as well as the environment in which such operations are undertaken. Temperature and corrosive environments often require specially coated wire ropes with increased durability. When dealing with industrial wire rope it is important to remember that rated load, breaking strength and other specifications are the measured capabilities under normal circumstances. Rust, kinks, fraying and even carefully performed splicing will all have an impact on the performance of wire ropes which should be inspected regularly and cleaned or lubricated as needed. Properly maintained wire ropes often boast a long working life and are therefore favored in many applications.
Wire rope - Sandin Manufacturing
Wire Rope Spools - Jersey Strand & Cable
Wire Rope Lanyards - Tyler Madison, Inc.
Since wire ropes replaced natural fiber ropes, including hemp and manila, in the mid 18th century in Germany for mining purposes, wire ropes have become a staple in range of industries. Wherever heavy-duty lifting is involved, including bridge construction, oil rigging, towing of vehicles, and lifting by cranes, wire rope is used.
As wire ropes are used in different environments, different wire ropes have distinct characteristics. The selection of wire ropes depends on a number of factors. Therefore, it is necessary that all the factors be weighed properly before buying one.
To determine the safety factor, which is a margin of security against risks, the first step involves knowing the type of load that the rope will be subjected to. The load must consider the shock loads and blowing wind effects. The safety factor is characterized in ratios; typical are 4:1 and 5:1. If a ratio is 5:1, then the tensile strength of a wire rope must be five times of the load it will be subjected. In some applications, the ratios can go up to 10:1.
Based on different needs, wire ropes can be constructed in a number of ways. For different applications, strands and wires are arranged in different geometrical forms. They are divided based on nominal number of wires and the number of strands. The common types are 6 x19, 6 x 25, 19 x 7, 7 x 7, 7 x 19, 6 x 26, and 6 x 36. There is no all-purpose wire rope, for instance, a door-retaining lanyard wire rope has a 7 x 7 construction, whereas wire rope for guying purposes has a 1 x 19 construction. It is evident that the application helps to determine the construction of a wire rope.
While choosing a wire rope, ability to bend is a big factor, as it determines whether the rope will break or not over time when repeatedly exposed to bending. A variety of parameters decides the bending ability: first being the diameter of wires used for making the rope. Second, is the rope and strand construction, and third, is the metal composition and finishing, including galvanizing. However to simplify the selection, there is a rule of thumb, the wire rope with more wires are bendable; if fewer and larger wires are used for making wire rope, the wire rope loses its ability to bend.
Wire ropes with higher fatigue resistance withstand duress that it is exposed to during lifting operations without damaging itself. Other than the number of wires, fatigue resistance is determined by the diameter of wires and metallurgy. The rule that defines the bending a wire also applied to fatigue resistance, that is a rope made of many wires have greater fatigue resistance.
By weighing all these factors carefully, the wire rope that you will buy will be safe to use and last considerably.
A wire rope is a type of cable that includes several wire strands laced together to form a single wire. Generally, both the terms-wire and rope-are used interchangeably; however, according to the technical definition of a wire rope; it has a thickness of at least 9.52 mm.
Common Types of Rope
Steel Wire Rope
Iron and steel are the two most common materials used in producing wire ropes. A steel wire is normally made from non-alloy carbon steel that offers a very high strength and can support extreme stretchable forces.
This category includes wires that have different layers or strands that cross each other to form an even stronger cable or rope. Wire strands are used in parallel lay strands, in which the length of all the wires is the same, and any two parallel wires are in linear contact. The wires are intertwined in a way that one external wire is supported by two wires in the inner layer. This pattern remains similar throughout the length of the wire.
Technically, spiral ropes are curved or round strands with an assemblage of wires. This gathering of wires has at least one cord situated in the opposite direction of the wire in the outer layer of the rope. The most important trait of this rope is that all the wires included are round. The biggest benefit of this category of rope is that it does not allow the entrance of pollutants, water, or moisture.
Stranded ropes contain an assemblage of strands placed spirally around a core. Stranded ropes contain one of three types of core: a fiber core, a wire strand core, or a wire rope core.
Other common categories of ropes include running ropes, stationary ropes, and track ropes.
Common Types of Slings
Wire Rope Slings
Wire rope slings provide an added level of security to a manufacturing production application. Wire rope slings are made from improved plow steel wire ropes that, apart from offering added security, also provide superior return loop slings. Plow steel wire ropes improve the life of a mechanism by shielding the rope at its connection points. The key objective of wire rope slings is to enhance the safety of an application while increasing its capacity and performance. Rope slings are also available in various sling termination options, such as hook type, chokers, and thimbles.
Permaloc Rope Slings
The eye in this rope sling is made using the Flemish Splice method. Just like a typical sling, a Permaloc rope sling improves safety and provides reverse strength meaning that the uprightness of the eye does not depend on the sleeves of the metal or alloy. Additionally, permaloc rope slings offer an abrasion resistance feature that makes them long lasting.
Permaloc Bridal Slings
These slings have all the features that most other slings offer. However, compared to their counterparts, Permaloc bridal slings provide better load control, wire rope resistant crushing, robust hooks and links that work for a longer duration, and help save on maintenance requirements.
Grommets and endless slings are also available to manufacturers. With their movable legs, these slings offer unmatchable load stability and balance, which, ultimately, improve safety.
- Element of a wire rope around which the strands are helically laid. The core could be made of fiber (cloth), independent wire rope or wire strand.
- A round and flanged barrel, which is tapered or uniform in diameter for storage or operation, around which rope is wound.
- Steel that is designed for applications, which require greater safety features with no increase in diameter size and the highest resistance to abrasive wear. This steel is fifteen percent stronger than Improved Plow Steel, and the tensile strength of this grade ranges from 280,000 to 340,000 psi.
- To coat with zinc for the protection of the wire, strand or rope from corrosion.
- A classification according to breaking strength.
- Steel wire or strand, typically galvanized, that braces or supports a structure.
- A high-carbon steel having a tensile strength of approximately 260,000 psi that is roughly fifteen percent stronger than Plow Steel. Most commercial wires are made from IPS.
- Wire rope that serves as the core for a greater rope.
- A low carbon steel wire of approximately 10,000 psi, which is pliable and capable of repeated stresses from bending around small sheaves. This grade is effective for tillers, guys and sash ropes.
- The manner in which the wires are helically wound to form rope. Lay refers specifically to the direction of the helical path of the strands in a wire rope; for example, if the helix of the strands are like the threads of a right-hand screw, the lay is known as a right lay, or right-hand, but if the strands go to the left, it is a left lay, or left-hand.
- A classification of wire rope according to its breaking strength. The rank of grades according to increasing breaking strengths is as follows: Iron, Traction, Mild Plow Steel, Plow Steel, Improved Steel, Extra Improved Steel.
- A pulley wheel with a channel, mounted in a frame, that guides or alters the direction of the cable or rope.
- An assembly of wires that are helically wound around an axis, fiber or wire center (core) to create a symmetrical portion.
- Classification of strands according to breaking strength. The ranking of increasing breaking strengths is as follows: Common, Siemens Martin, High Strength and Extra-High Strength; a utility's grade strand is available for certain requirements.
- The act of fastening a termination to a wire rope through physical deformation of the termination about the rope via a hydraulic press or hammering. The strength is one hundred percent of the wire rope rating.
- Fittings into which wire rope can be inserted and fastened through a cold flow method.
- A grade of rope material that has a tensile strength range of 180,000 to 190,000 psi. Traction steel has great resistance to bending fatigue with a minimum of abrasive force on sheaves and drums, which contributes to its long use in elevators, from which the steel gets its name.
- A continual span of metal that has been cold drawn from a rod.