What Is Wire Rope?

Wire ropes, often used as crane wire ropes, are several strands of metal wire that are twisted into a helix to form a composite rope, known as a laid rope. Large diameter wire rope consists of several strands of rope laid in what is known as cabling.

Wire ropes are complex mechanical devices consisting of several moving parts that work together to help support & move an object or load.

In the lifting & rigging industries, wire rope for crane is attached to a crane or hoist & fitted with a swivel, shackle, or hook to attach to a load and move it into a controlled case.

It can also be used for lifting and lowering elevators or as a means of support for suspension bridges or towers. Wire rope is a preferred lifting tool for many reasons.

Its unique design, often seen in 6 strand wire rope, consists of several steel wires that form separate strands placed in a helical pattern around a core. These structures provide strength, flexibility, & the ability to handle bending stresses.

In the strictest sense, the term wire rope refers to a diameter larger than 3/8 inch (9.52 mm), with a smaller gauge specified cable or cord. Initially, iron wires were used, but today, with various wire rope materials available, the main material used for wire ropes is steel.

Wire rope is made from cold-drawn wires to increase strength & durability. It may be noted that as its size decreases, the strength of the wire ropes increases. The various materials used for wire ropes are iron, cast steel, extra strong cast steel, steel, and alloy steel, in order of increasing strength.

For some purposes, wire rope can also be made from copper, bronze, aluminum alloys, and stainless steel. Wire ropes were developed in the 1830s with mining hoist applications.

Wire ropes, including specific wire ropes for cranes, are used in cranes and elevators for dynamic lifting and lifting and for transmission of mechanical power.

It is also used to transmit forces to mechanisms, such as Bowden cables or the control surface of an airplane connected to levers and pedals in the cockpit.

Types of Wire Rope

Wire rope is made of threads of metal wire that are braided together to form a helix. Due to its heavy, flexible and tough characteristics, as well as being weather- and corrosion-resistant, it is commonly used in the building and construction, engineering, agriculture, aircraft, and marine industries.

Each wire strand bringing equal pressure to the bundle contributes to its strength and flexibility, making it an ideal material for pulleys. In Australia, wire rope was made of iron; Today, the materials used are mainly steel. Different industries use different types of wire ropes.

This is because the suitability of a specific wire rope for an application depends on the design, size, type of braids, and other characteristics.

For example, marine-grade 316 wire rope is suitable for a variety of marine applications and settings. There are three main types, stainless steel, galvanized, and coated wire rope.

1. Stainless Steel

Stainless steel is the standard alloy used in rope and cable. Its resistance to corrosions is much higher than that of galvanized & coated ropes, although there are no differences in strength.

Therefore, it is the preferred material uses in marines and water-based salt industries. It does not readily react to chemicals from food processing, textiles, and photographic settings.

Its high resistance to corrosion, heat & cold, and pulp & paper chemicals makes stainless steel wire rope a much-needed material for manufacturing precision instruments, automobiles, fishing vessels, petrochemical equipment, & other fields.

2. Galvanized Wire Rope

Galvanized wire ropes are also steel wire materials that have undergone a galvanizing process to increase their corrosion resistance. The finished wire is immersed in a zinc bath to coat the product completely, i.e., it is galvanized.

Zinc is used in this process because cathode protection increases the life expectancy of the wire.  Although the coating will degrade over time, it is still resistant to rust, corrosion, and other harsh chemicals.

Galvanized wire can be found in the industrial and construction sectors as well as in agricultural and DIY projects.

3. Coated Wire Rope

Stainless steel and galvanized wire can be PVC coated with poly-vinyl-chloride or vinyl. Coated wire rope comes in various colors such as clear, black, white, or any other color that is required in various industries. PVC coated wire is flexible, weather-resistant, and very cost-effective.

Nylon-coated wire, although not as flexible as PVC, is abrasion-resistant and ideal for businesses in extremely cold regions. Wire ropes can be assembled to suit specific applications. If you have a project requiring a specific type of wire rope, send us an inquiry, and we’ll send you a special quote.

Components of Wire Rope:

1. Wire

The wire is the smallest component of wire rope, and they form the individual strands in the rope. Wire can be made from a variety of metal materials, including steel, iron, stainless steel, Monel, and bronze.

Wires can be manufactured in varieties of grades that are related to wire rope strength, wear resistance, fatigue resistance, corrosion resistance, and curve.

These strings symbolize the smallest component of a wire rope and are tied together around a core to form complete wire ropes. The wire themselves can be coated but are usually available in “bright” or uncoated finishes.

2. Strands

Wire rope strings form two or more wires wrapped around an axial member in a geometric pattern or in combination with steel wires and other materials.

These individual strands are then placed around the core in a helical pattern. Strands represent the major part that serves as the primary load-bearing unit.

A typical wire rope strand can form any number of strands, and the same goes for a rope that can have an ‘n’ number of strands. Wires made from larger diameter wires are more resistant to abrasion, while wires made of smaller diameter wires are more flexible.

3. Core

The core, an essential wire rope part, runs through the center of the rope & supports the wires and helps them maintain their relative position under loading and bending stress.

Cores, contributing to the wire rope structure, can be made from many different materials, including natural or synthetic fibers and steel. It supports the strands and helps maintain their relative position under loading and bending stress.

Construction of Wire Rope:

Wire ropes, with various types of steel wire incorporated, are made from the various grades of steel wires with tensile strengths ranging from 1200 to 2400 MPa.

The wires, integral to wire rope construction, are first given special heat treatment & then cold drawn for the high strength and durability of the rope. Steel wire ropes are manufactured by special machines.

First, strands of wire such as 7, 19, or 37 are routed into a single strand, and then several strands, usually 6 or 8, are twisted around the core or center to form a rope. The core may be made of loops of hemp, jute, mica, or soft steel wire.

The core must be continuously saturated with lubricants for the long lives of the core as well as the entire rope. Asbestos or soft wire core is used when a rope is subjected to radiant heat, such as cranes working near furnaces.

However, a wire core reduces the rope’s flexibility, and such ropes are only used where they are subject to high compression, as in the case of multiple layers being injured on a rope drum.

 

The following terms help define the construction and properties of wire rope:

1. Length

A total number of legs cut to size when wrapped and distributed around the spool.

2. Size

These are the specified nominals diameters of the wire rope & can be specified in inches or millimeters.

3. Strand Patterns

The number of layers of wires, the numbers of wires per layer, & the size of the wire per layer all affect the strand pattern type. Wire ropes can be constructed using any one of the following patterns or can be made using two or more of the pattern below.

3.1. Single Layer

The most common example is a seven-wire strand with a single-wire center and six wires of the same diameter around it.

3.2. Filler Wire

The Two-layer of similarly sized wire around a center whose inner layer is half the number of wires as the outer layer. Small fillers wires, equal to the numbers in the inner layer, are placed in the valleys of the inner wire.

3.3. Seale

Two layers of wires around centers with the same numbers of wires in each layer. All wire in each layer is of the same diameter. The larger outer strings rest in the valleys between the smaller inner strings.

3.4. Warrington

The inner layer consists of two layers of wires around a center with one diameter of the wire, and the latter alternates two diameters of the larger and smaller wire in the outer. The larger wires in the outer layer are placed in the valleys & the smaller ones on the crowns of the inner layer.

3.5. Combination

The combinations strand is constructed using any combination of two or more of the patterns listed above.

4. Preformed or Non-Preformed

On a prefabricated wire rope, the wire and wire are formed during the manufacturing process into the helical shape that they will take into a finished wire rope.

Prefabricated rope can be beneficial in some applications where it needs to be spooled more evenly over the drum, more flexibility is required, or greater fatigue resistance is required when bending.

5. Direction and Type of Lay

Direction and laying type refer to how the wires are laid to form a strand, either right or left & how the strands are laid around the regular core lay, lang lay, or alternate lay.

5.1. Regular Lay

The wires are lined up with the axis of the rope. The direction of the wire held in the strand is opposite to the direction in the strand lay. Regular lat ropes are more resistant to crushing forces, are more naturally rotation-resistant, and also have a better spool in the drum than lang lat ropes.

5.2. Lang Lay

The wires make an angle with the axis of the rope. The wire lay down, and the strand lay around the core in the same direction. Lang le ropes have greater fatigue resistance and are more resistant to abrasion.

5.3. Alternate Lay

Wire rope consists of alternating regular le and lang le strands – mainly used for special applications.

6. Finish of Wires

Zinc coated galvanized, zinc/aluminum alloy coated mischmetals, stainless steels, or unfinished steel “bright.”

7. Grade of Rope

Wire rope strength is divided into various grades, including:

1. Improved Hull Steel (IPS)
2. Extra Advanced Hull Steel (EIPS) is 15% stronger than IPS
3. Extra Advanced Hull Steel (EEIPS) is 10% stronger than EIPS

Hull Steel’s strength curve forms the basis for calculating the strength of most steel rope wires.

8. Type of Core

Wire rope cores are designated as:

1. Fiber Core (FC)
2. Independent Wire Rope Core (IWRC)
3. Wire Strand Core (WSC)

A fiber core may be made of natural or synthetic polypropylene fibers. Fiber cores offer greater elasticity than steel cores but are more susceptible to crushing and are not recommended for high heat environments. A steel core can be independent wire ropes or an individual strand.

Steel cores are bests suited for applications where the fiber core cannot provide adequate support or in an operating environment where temperatures may exceed 180 degrees Fahrenheit. Based on what we have learned above, this wire rope description will provide the following information to the user:

6 x 25 FW EIP RRL IWRC:

1. Diameters = 1″
2. Numbers of Strands = 6
3. Number of Wires Per Strand = 25
4. Strand Pattern = Filler wires
5. Grade = Extra Improved Plow Steel
6. Direction and Lay = Rights Regular Lay
7. Core Type = Independent Wire Rope Core

Different Types of Wire Rope:

Wire rope classifications provide the total number of wires in each strand, as well as the nominal or an exact number of wires.

These are general classifications & may or may not reflect the actual constructions of the strands. However, all wires rope of the same size & wires grade in each classification will have similar strength and weight ratings and generally similar pricing.

1. Rotation Resistant Wire Rope

Some types of wire rope, particularly lang le wire rope, are more susceptible to rotation under load. Rotation-resistant wire rope is designed to resist twisting, spinning, or twisting and can be used in a single-line or multi-part system.

Special care should be taken when handling, unrolling, and installing rotation-resistant wire rope.  Improper handling or spooling can introduce a twist in the rope, which can lead to uncontrolled twisting.

2. Compact Strand Wire Rope

Compact Strand Wire Rope is manufactured using strands that have been compacted, by means of passing through a die or rollers, reducing the outside diameter of the entire strand.

This process occurs before the rope is closed. This process flattens the surfaces of the outer strands in the strand but also increases the density of the strand.

This resulted in a smoother outer surface and increased strength compared to comparable round wire rope compare similar diameters and assortments while also helping to increase surface life due to increased wear resistance.

3. Compact / Swaged Wire Rope

A swaged wires rope differs from a compacted strand wires rope in that the diameter of a swaged wire rope is compacted or reduced by a rotary swagger machine after the wire rope is closed. A curved wire rope can be manufactured using rounded or narrower wires.

The advantages of a swaged wires rope are that they are more resistant to wear, has better crushing resistance, and has higher strength than a round strand wire rope of similar diameter and assortment. However, a swaged wire rope may have low bending fatigue resistance.

4. Plastic Coated Wire Rope

The plastic coating may be applied to the outer surface of a wire rope to provide protection from abrasion, wear, and other environmental factors that can cause corrosion. However, because you can’t see the individuals strand & wires beneath the plastic coating, they can be difficult to inspect.

5. Plastic Impregnated (PI) Wire Rope

Plastic-filled wire ropes are fitted with a plastic matrix where the wires and the internal spaces between the wires are filled. Plastic fillings help improve bending fatigue by reducing wear internally and externally. Plastics-filled wire rope is used for demanding lifting applications.

6. Plastic Filled IWRC Wire Rope

This type of wires rope uses an independent wires rope core (IWRC) that is either filled with plastics or coated in plastic to reduce internal wear & increase bending fatigue life.

Frequently Asked Questions (FAQ) about Wire Rope

What Is Wire Rope?

Wire rope is a composite rope made from several strands of metal wire twisted together to form a helical pattern. It is commonly used in lifting, rigging, and support applications due to its strength and flexibility.

What Materials Are Used to Make Wire Rope?

Wire ropes are typically made from steel, but can also be made from other materials such as stainless steel, galvanized steel, bronze, aluminum alloys, and copper. Steel is the most common material due to its strength and durability.

What Are the Main Types of Wire Rope?

The main types of wire rope are:

1. Stainless Steel Wire Rope: Known for its high resistance to corrosion and suitability for marine and chemical environments.
2. Galvanized Wire Rope: Coated with zinc to improve corrosion resistance; commonly used in construction and industrial applications.
3. Coated Wire Rope: Covered with materials like PVC or nylon for added flexibility and weather resistance.

What Are the Key Components of Wire Rope?

Wire rope consists of:

1. Wires: The individual metal strands that form the rope.
2. Strands: Groups of wires twisted together to form the rope’s main load-bearing units.
3. Core: The central component that supports and maintains the relative position of the strands under load.

How Is Wire Rope Constructed?

Wire rope is constructed by twisting multiple strands around a core. The strands are made from multiple wires arranged in a geometric pattern. The core can be made from natural fibers, synthetic fibers, or steel.

What Are the Different Strand Patterns Used in Wire Rope?

Common strand patterns include:

1. Single Layer: A center wire surrounded by six wires of the same diameter.
2. Filler Wire: Two layers of wires with smaller filler wires in the valleys of the inner layer.
3. Seale: Two layers of wires with the outer layer being larger.
4. Warrington: Two layers of wires with alternating sizes in the outer layer.
5. Combination: A mix of two or more strand patterns.

What Is the Difference Between Regular Lay, Lang Lay, and Alternate Lay Wire Ropes?

1. Regular Lay: Wires are aligned with the rope’s axis, offering resistance to crushing forces and better rotation resistance.
2. Lang Lay: Wires are laid at an angle with the rope’s axis, providing greater fatigue resistance and abrasion resistance.
3. Alternate Lay: Combines regular and lang lay strands, used for specialized applications.

What Is the Significance of the Core Type in Wire Rope?

The core type affects the wire rope’s strength and flexibility. Core types include:

1. Fiber Core (FC): Provides greater elasticity but is less resistant to crushing and high temperatures.
2. Independent Wire Rope Core (IWRC): Offers higher strength and support, suitable for heavy-duty applications.
3. Wire Strand Core (WSC): Similar to IWRC but with a different internal structure.

How Is the Strength of Wire Rope Graded?

Wire rope strength is graded based on the steel quality and tensile strength. Common grades include:

1. Improved Plow Steel (IPS)
2. Extra Improved Plow Steel (EIPS): 15% stronger than IPS
3. Extra Extra Improved Plow Steel (EEIPS): 10% stronger than EIPS

What Is the Purpose of Plastic Coating or Impregnation in Wire Rope?

Plastic coating or impregnation protects the wire rope from abrasion, corrosion, and environmental factors. It can improve wear resistance and bending fatigue life but may make inspection more difficult.

How Do I Choose the Right Wire Rope for My Application?

Consider factors such as the type of load, environmental conditions, required strength, flexibility, and specific industry standards when selecting wire rope. Consult with experts if needed to ensure the rope meets the requirements of your application.