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Wire rope is a machine consisting of wires laid around a central core. This high strength,
flexible piece of equipment is ideal for heavy lifting and positioning. With resistance to
damage from heat, sunlight, chemicals, and water, wire rope is relied on for lifting
applications around the world by the construction, industrial, mining, wind, military, and
A wire rope is a piece of flexible, multi-wired, stranded machinery made of many precision parts.
Usually a wire rope consists of a core member, around which a number of multi-wired strands are
“laid” or helically bent.
There are two general types of cores for wire rope - fiber cores and wire cores. The fiber core
may be made from natural or synthetic fibers. The wire core can be an Independent Wire Rope Core
(IWRC), or a Strand Core (SC).
The purpose of the core is to provide support and maintain the position of the outer strands
during operation. Any number of multi-wired strands may be laid around the core. The most
popular arrangement is six strands around the core, as this combination gives the best balance.
The number of wires per strand may vary from 3 to 91, with the majority of wire ropes failing
into the 7-wire, 19-wire, or 37- wire strand categories.
Lays of Wire Rope
“Lay” of a wire rope is simply a description of the way wires and strands are placed during
construction. Right lay and left lay refer to the direction of strands.
Right lay means that the strands pass from left to right across the rope. Left lay means just the
opposite: strands pass from right to left.
Regular lay and lang lay describe the way wires are placed within each strand. Regular lay means
that wires in the strands are laid opposite in direction to the lay of the strands. Lang lay
means that wires are laid in the same direction as the lay of the strands.
Most of the wire rope used is right lay, regular lay. This specification has the widest range of
applications and meets the requirements of most equipment. In fact, other lay specifications are
considered exceptions and must be requested when ordering.
Exceptions to the Rules
Lang lay is recommended for many excavating, construction, and mining applications, including
draglines, hoist lines, dredgelines and other similar lines.
Here's why: Lang lay ropes are more flexible than regular lay ropes. They also have greater
wearing surface per wire than regular lay ropes.
Where properly recommended, installed and used, lang lay ropes can be used to greater advantage
than regular lay ropes. However, lang lay ropes are more susceptible to the abuses of bending
over small diameter sheaves, pinching in undersize sheave grooves, crushing when winding on
drums, and failing due to excessive rotation.
Left lay rope has greatest usage in oil fields on rod and tubing lines, blast hole rigs, and
spudders where rotation of right lay rope would loosen couplings. The rotation of a left lay
rope tightens a standard coupling.
Left Lay - REGULAR LAY
Right Lay - LANG LAY
Right Lay - REGULAR LAY
LEFT LAY - LANG LAY
ALTERNATE RIGHT LAY
Wire Rope Strand Constructions
Wire ropes are composed of independent parts -- wires, strands and cores -- that continuously
interact with each other during service.
Wire rope engineers design those parts in differing steel grades, finishes and a variety of
constructions to attain the best balance of strength, abrasion resistance, crush resistance, bending
fatigue resistance and corrosion resistance for each application.
To select the best wire rope for each application, one must know the required performance
characteristics for the job and enough about wire rope design to select the optimum combination of
wire rope properties.
Strands are designed with various combinations of wires and wire sizes to produce the desired
resistance to fatigue and abrasion. Generally, a small number of large wires will be more abrasion
resistant and less fatigue resistant than a large number of small wires.
The basic strand construction has wires of the same size wound around a center.
Large outer wires with the same number of smaller inner wires around a core wire. Provides
excellent abrasion resistance but less fatigue resistance.
Small wires fill spaces between large wires to produce crush resistance and a good balance of
strength, flexibility and resistance to abrasion.
Outer layer of alternately large and small wires provides good flexibility and strength but low
abrasion and crush resistance.
Many commonly used wire ropes use combinations of these basic constructions. These strand designs
can also be covered with one or more layers of uniform-sized wires to create a multiple
Some common combinations of these basic strand constructions include:
See more common wire rope constructions:
Seale Filler Wire
Filler Wire Seale
Seale Warrington Seale
Wire Rope Grades and Finishes
Bright finish is suitable for most applications. Galvanized finish is available for corrosive
environments. Plastic jacketing is also available on some constructions.
The most common steel wire grades are: IPS (Improved Plow Steel), EIP (Extra Improved Plow Steel) and
EEIP (Extra Extra Improved Plow Steel). Stainless Steels and other special grades are provided for
Most wire ropes are made with round wires. Both triangular and shaped wires are also used for special
constructions. Generally, the higher the strength of the wire, the lower its ductility will be.