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The Specifications and Construction Of Wire Rope

Time: 2018-11-26

What is Wire Rope

 Wire rope has a unique design consisting of steel wires that form individual strands laid in a helical pattern around a center core.


Wire rope is several strands of metal wire twisted into a helix forming a composite "rope", in a pattern known as "laid rope". Larger diameter wire rope consists of multiple strands of such laid rope in a pattern known as "cable laid"
In stricter senses the term "wire rope" refers to diameter larger than 3/8 inch (9.52 mm), with smaller gauges designated cable or cords.Initially wrought iron wires wereused, but today steel is the main material used for wire ropes.
Wire rope is a complex mechanical device that has many moving parts all working in tandem to help support and move an object or load. In the lifting and rigging industries, wire rope is attached to a crane or hoist and fitted with swivels, shackles or hooks to attach to a load and move it in a controlled matter. It can also be used to lift and lower elevators, or as a means of support for suspension bridges or towers.
In fact, wire rope is a complicated machine. A typical 6 x 25 rope has 150 wires in its strands, all of which move independently and together in a very complicated pattern around the core as the rope bends. Clearances between wires and strands are balanced when a rope is designed so that proper bearing clearances will exist to permit internal movement and adjustment of wires and strands when the rope has to bend. These clearances will vary as bending occurs, but are of the same range as the clearances found in automobile engine bearings.

Components of Wire Rope

A finished wire rope is comprised of individual wires, make up individual strands, which are then laid in a helical pattern around a synthetic or steel core.


Wires are the smallest component of wire rope and they make up the individual strands in the rope. Wires can be made from a variety of metal materials including steel, iron, stainless steel, monel, and bronze. The wires can be manufactured in a variety of grades that relate to the strength, resistance to wear, fatigue resistance, corrosion resistance, and curve of the wire rope.
The wires themselves can be coated but are most commonly available in a “bright” or uncoated finish.


Strands of wire rope consist of two or more wires arranged and twisted in a specific arrangement. The individual strands are then laid in a helical pattern around the core of the rope.
Strands made of larger diameter wires are more resistant to abrasion, while strands made of smaller diameter wires are more flexible.
Strand is two or more wires wound concentrically in a helix. They are usually wound around a center wire. Strand is normally referred to as 1 by the total number of wires in the given strand. Such as 1 x 7 (one group of seven wires) or 1 x 19 (one group of nineteen wires).


The core can be a variety of things, including: Strand in many constructions or even a cable or wire rope. The core can also be of a composition other than metal, such as polypropylene rope. Whatever the construction or the composition of the core, it is the center member of the cable or wire rope.
The core of a wire rope runs through the center of the rope and supports the strands and helps to maintain their relative position under loading and bending stresses. Cores can be made from a number of different materials including natural or synthetic fibers and steel.


Lubrication is applied during the manufacturing process and penetrates all the way to the core. Wire rope lubrication has two primary benefits:

  1. Reduces friction as the individual wires and strands move over each other
  2. Provides corrosion protection and lubrication in the core, inside wires, and outside surface
Feature of wire rope
1.Wire ropes can carry loads over long distances.
2. Large bearing safety factor, safe and reliable in use.
3. Light weight, easy to carry and transport.
4. Able to withstand multiple loads and variable loads.
5. High tensile strength, fatigue strength and impact toughness.
6. Under high-speed working conditions, wear-resistant, anti-seismic and stable operation.
7. Good corrosion resistance, able to work normally in the harsh environment with various harmful media.
8. Good softness, suitable for pulling, pulling, strapping and other purposes.

Wire Rope Construction

The total number of feet (cut to size) when wrapped around the spool and delivered.
This is the specified nominal diameter of the wire rope and can be specified in inches or millimeters.
Strand Patterns
The number of layers of wires, the number of wires per layer, and the size of the wires per layer all affect the strand pattern type. Wire rope con be constructed using one of the following patterns, or can be constructed using two or more of the patterns below.
Single Layer – The most common example is a 7 wire strand with a single-wire center and six wires of the same diameter around it.
Filler Wire – Two layers of uniform-size wire around a center with the inner layer having half the number of wires as the outer layer. Small filler wires, equal to the number in the inner layer, are laid in valleys of the inner wire.
Seale – Two layers of wires around a center with the same number of wires in each layer. All wires in each layer are the same diameter. The large outer wires rest in the valleys between the smaller inner wires.
Warrington – Two layers of wires around a center with one diameter of wire in the inner layer, and two diameters of wire alternating large and small in the outer later. The larger outer-layer wires rest in the valleys, and the smaller ones on the crowns of the inner layer.
Combination – A combination strand is constructed using any combination of two or more of the patterns listed above.
Preformed or Non-Preformed
On a preformed wire rope, the strands and wires are formed during the manufacturing process to the helical shape that they will take in a finished wire rope.
Preformed rope can be advantageous in certain applications where it needs to spool more uniformly on a drum, needs greater flexibility, or requires more fatigue-resistance when bending.
Direction and Type of Lay

Direction and type of lay refer to the way the wires are laid to form a strand (either right or left) and how the strands are laid around the core (regular lay, lang lay, or alternate lay).
Regular Lay – The wires line up with the axis of the rope. The direction of the wire lay in the strand is opposite to the direction of the strand lay. Regular lay ropes are more resistant to crushing forces, are more naturally rotation-resistant, and also spool better in a drum than lang lay ropes.
Lang Lay – The wires form an angle with the axis of the rope. The wire lay and strand lay around the core in the same direction. Lang Lay ropes have a greater fatigue-resistance and are more resistant to abrasion.
Alternate Lay – The wire rope consists of alternating regular lay and lang lay strands—used mainly for special applications.

Other Information

The steel wire is made of high quality carbon steel and can reach high strength after several cold drawing and heat treatment.Galvanized steel wire rope can be used in damp or outdoor environments to enhance rust resistance.
The steel wire rope is the standard product in each industrial country, may select its diameter, rope stock, each steel wire number, tensile strength and sufficient safety factor according to the need of use, its specification model may check in the concerned manual.Steel wire rope, except the wear of layer steel wire, is broken gradually due to metal fatigue caused by repeated bending when bypassing pulley and reel. Therefore, the ratio of diameter of pulley or reel and wire rope is an important factor to determine the life of wire rope.High ratio, low bending stress, long life, but large structure.The appropriate ratio must be determined according to the situation.The surface layer of the wire rope shall be scrapped when the wear, corrosion degree or the number of broken wires within each twist distance exceeds the specified value.
Steel wire rope is mainly used in lifting, drawing and other high-strength wire rope transport.

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