Special Steel Wire Ropes

As has previously been mentioned, there are many types of construction/design of steel wire ropes, which is why it is also possible to design a steel wire rope that meets the particular requirements for a given application.
Randers Reb has specialised in the development of special steel wire ropes that can meet such special requirements. Get in touch with us and find out how we can help solve your problems.
Through the years Randers Reb has produced/developed many special steel wire ropes. Some of these special steel wire ropes are now part of our standard product range.

  • Compacted steel wire rope
  • Cable lay steel wire rope
  • Low rotation and rotation resistant steel wire rope
  • Coated steel wire rope
  • Combination rope
  • Sisal/Danline clad wire rope
  • Cobra

Compacted Steel Wire Rope
In compacted steel wire ropes the strand’s dimensions are reduced (compacted) before the actual laying of the steel wire rope. There are different ways of reducing the dimension of a strand:

  • By drawing between rollers (compacting)
  • By drawing between dies (Dyform)
  • By beating (hammering)

In individual cases the compacting process is only carried out after the steel wire rope has been laid. In this instance only the outer part of the steel wire rope is compacted (fig. 19).
The various methods do not all produce the same level of quality. In the opinion of Randers Reb, the best quality is achieved by drawing the strands between rollers, after which the laying process is carried out.
Compacted steel wire ropes have greater abrasion resistance and tensile strength than corresponding non-compacted steel wire ropes.

rope technology fig 19rope technology fig 20

Cable Laid Steel Wire Rope

In a cable laid steel wire rope the strands consist of a 6-lay steel wire rope with WSC (e.g. 6x7 + WSC or 6x19 + WSC). The core in the cable laid steel wire rope can be either FC or IWRC (fig. 20).
A 6x(6x19 + WSC) + IWRC contains a total of 931 wires. The high number of wires has the effect of making the steel wire rope ­incredibly pliable/flexible and thus ideal for slings.

Low-Rotation and Rotation-Resistant Steel Wire Rope

A low-rotation or rotation-resistant steel wire rope is a special steel wire rope designed not to turn or rotate when bearing a load. (fig. 21 og 22)

rope technology fig 21rope technology fig 22


There are two types of low-rotation and rotation-resistant steel wire ropes available:

  • One layer of strands. There are three or four strands. The steel wire rope has either no core or a fibre core
  • Spiral lay, i.e. two or more layers of strands

The number of outer strands is normally between eight and 20. The core may be either fibre or steel.

These steel wire ropes are normally used in single-strand units, or in multi-strand units for heavy loads and/or significant lifting heights. The special design results in limited applications for this type of rope and imposes special handling requirements, such as:

  • Larger sheaves than for normal steel wire ropes.
  • Less surface pressure.
  • Optimal grooves in sheaves
  • Small fleet angle on winch
  • Preferably one layer on the drum
  • Use of swivels is often necessary
  • Increased safety factor.
  • The steel wire ropes are normally not pre-formed.
    Consequently the wire rope has to be seized before cutting (alternatively welded ends) to avoid the steel wire rope unwinding (destroying the balance in the rope).
  • During installation great care must be taken not to subject the steel wire rope to tension, e.g. caused by turning/twisting.

If you are in any doubt as to the use of low-rotation and rotation-resistant steel wire ropes, please contact your local salesman or our Technical Department.

Coated Steel Wire Rope

A coated steel wire rope is one that has been coated with a plastic material such as PP, PE, PVC or PA, depending on its intended application (fig. 23).

rope technology fig 23 24
The coating protects the steel wire rope against rust and wear and tear. Other advantages are e.g. that its life expectancy when running over the sheaves is increased significantly. Furthermore, any wires that might break will not cause damage to objects in the proximity of the steel wire rope.

Combination Rope

Taifun is Randers Reb’s trade name for a special combination rope, in which the steel strands are wrapped up in fibre yarns (fig. 24).
Combination rope is ­produced with FC or IWRC. Combi­nation rope combines the properties of fibre ropes and steel wire ropes: The strength and minimal elongation of the steel wire rope, and the “soft” surface and flexibility of the fibre rope.

Combination rope is used primarily for strengthening fishing nets, but may also be used for swings, climbing nets and for applications in industry/farming that require particularly durable ropes.

Sisal/Danline clad wire rope

Sisal/Danline clad wire rope is a special steel wire rope in which the steel strands are wrapped in a combination of fibre yarns (Danline) and sisal yarns. Sisal/Danline clad wire rope is produced primarily with FC (fig. 25), but can also be produced with IWRC.

rope technology fig 25 26

The sisal yarns expand when wet, causing the Sisal/Danline clad wire rope to have increased ability to secure objects/materials that are tied to the rope. In other respects the Sisal/Danline clad wire rope has the same properties as the combination rope. The Sisal/Danline clad wire rope is used to strengthen fishing nets.

Cobra

Cobra is Randers Reb’s trade name for a special spring lay wire rope in which the strands are 6-lay rope with FC. Three of the strands are steel, and the other three strands are fibre rope. Cobra is produced primarily with FC (fig. 26), but can also be produced with IWRC.

The special construction of the strands means that the rope has a greater tensile elongation than standard steel wire ropes and combination rope, which makes Cobra ideal as a mooring rope on a tug boat.