Spiral wire ropes / Stranded ropes

Ropes

Ropes can be in single stranding (spiral wire ropes) and in multiple stranding (stranded ropes). A spiral wire rope consists of one or several layers of wires which are wound helically round a core wire. Spiral wire ropes are well suited as clamping and supporting element.

A stranded rope consists of one or several layers of strands. The strands are helically wound round a core. This core can either be a fibre core or a core of stranded wires (steel core). Stranded ropes are used principally for dynamic and mechanical strain.

Construction of ropes

Ropes and stranded ropes are described as follows: (number of strands) x (number of wires per strand). If a cable with a fiber core is used, the designation FC is added.

E.g. the designation 6 x 7 – WSC describes a wire rope consisting of 6 strands. An individual strand contains 7 wires and the wire strand core has 1 x 7, i.e. a total of 49 wires.

Spiral wire rope
1×19

Stranded ropes with
a wire strand core
6×7 – WSC

Stranded ropes with
a fibre core
6×7 – FC

Stranded ropes with
a wire strand core
6×19 – WSC

Type of lay

The direction of lay of a rope is the direction of the helical line of the outer strands. Wire ropes are available in right-hand lay and in left-hand lay. By default and unless otherwise indicated, ordinary lay right uses.

Materials

By default, we offer ropes made of galvanized steel or stainless steel (1.4301 / 1.4401). For special requirements can also ropes made of other materials be processed.

Deflection

The following minimum roll diameter guarantee maximum lifetime for stranded ropes. Spiral ropes are not suitable for diversion.

Recommended minimum diameter of the rollers:

Rope TypeRoll – Ø
6x7 – WSC42 x Rope
6x19 – WSC25 x Rope

Elongation

A distinction is made between two types of stretching: Material-related and design-related stretching.

Material stretching
A wire stretches when under load, and returns approximately to its original state after the load is removed. If a wire is loaded beyond its deformation point (elastic limit) it will remain the stretched state, which leads to premature wire breaks, especially when mechanically stressed.

Design-related stretching
The process of stranding the individual wires creates interstices which close during the first loading. This causes a larger or smaller amount of stretching depending on the design.

Sheating

Sheathed cables should be used when they run over guide rollers or are subjected to flexural stresses. Sheathing wire cables with plastic protects the cable from dirt, and the oil film applied during the stranding process remains on the cable. The oil film acts as a lubricant between the individual wires and strands, reduces wear, and increases the lifetime by up to 50 %. We use transparent or black polyamide as standard. However, sheathing with other plastics is also possible.

Working life

The working life of a wire rope depends primarily on the following points:

• Rope type
• By deflection roll diameter
• Coating
• Percentage load of min. breaking force
• Rope lubrication

For a more accurate determination of working life, we offer endurance test.