What is a Wire Rope?
Wire rope can be a very complex product. There are a number of key factors which need to be considered when choosing which type of wire rope will provide optimum service life for your application. It is definitely not a one size fits all approach. To provide a bit of background on the make up of wire rope, let’s firstly go through the make up of the finished wire rope product:
A common wire rope construction is 6×36 with an independent wire rope core. The description of this would look like:
6×36 IWRC 1960 B sZ
This can be broken down into:
6 = number of strands
36 = number of wires in each strand
IWRC = the type of core, being Independent Wire Rope Core
1960 = the tensile strength of the individual wires used
B = galvanised, the finish of the rope
sZ = the lay of the rope, in this instance it is a Right Hand Ordinary Lay
Lang’s lay ropes offer greater wear resistance and minimise spooling damage at the cross-over zones when multi layers are wound onto a winch drum
Wire ropes can also be swaged after completion, further increasing the steel fill factor, whilst creating a smooth service to the exterior of the rope
CORES
Steel Wire Ropes are supplied with either fibre or steel cores, with the choice being largely dependent on the use for which the rope is intended.
The principal function of the core is to provide support to the strands and maintain them in the correct positions under working conditions
Steel cores comprise an independent wire rope (IWRC). These cores prove advantageous in severe working conditions, high operating speeds, wide fleet angles and are more resistant to crushing on drums and pulleys. The steel core provides better support for the outer strands, so that the rope retains its shape, resulting in a more effective distribution of stress in the individual wires
Generally, ropes are supplied preformed. In a preformed rope the wires and strands are given the helix that they take up in the completed rope
COATINGS
Zinc Coated Wire Ropes – Galvanising. Zinc coatings provide sacrificial protection to the underlying steel wire for protection against corrosion where the rope is exposed to corrosive agents – salt, water, moisture, weather, etc.
ROPE TENSILE GRADES
The higher the tensile grade the higher the breaking load of the wire rope. This is a very important consideration in the choice of your wire rope, but the tensile of the wire rope needs to be taken into account when considering other aspects such as d/D ratios on drums and sheaves
DEFINITION OF BREAKING LOADS AND FORCES
- Minimum Breaking Force: the force, in kilonewtons or pounds force which the rope shall not break below when tested to destruction
- Minimum Breaking Load: the load in tonnes or tons corresponding to the minimum breaking force
- Minimum Aggregate Breaking Force: the value calculated from the product of the sum of the cross-sectional metallic areas of all the individual wires in the rope and the tensile strength grades of the wires
If you would like further information, subscribe to our newsletter. They cover a range of information including:
- Selection of Steel Wire Ropes
- Discard Criteria of Steel Wire Ropes
- The Importance of Correct Wire Rope Installation
- Common Causes of Wire Rope Failure
- Ongoing Maintenance and Inspection Programmes for Wire Ropes
Have a specific enquiry? Contact the team at Crane Ropes Australia at wirerope@cranesropesaustralia.com.au
