Maintenance of Steel Wire Rope
The oil/grease that is added to the steel wire rope during production is only sufficient to protect the steel wire rope during the storage period and initial use. The steel wire rope must be lubricated regularly.
Thorough lubrication is extremely important for the steel wire rope’s life expectancy, as the purpose of lubrication is partly to protect the steel wire rope against rust, and partly to reduce friction between the wires and the strands in the steel wire rope. Friction is also thereby reduced between the steel wire rope and the surfaces with which it comes into contact.
The lubricant used must be free of acids and must not have a destructive effect on the steel wires, the fibre core and the environment. The lubricant must have a consistency that enables it to penetrate the core and the strands. The steel wire rope must be cleaned before lubrication.
To achieve maximum lubrication effect, the lubricant should be applied during operation, at a sheaf or on the drum, as this is where the steel wire rope opens up and makes it easier for the lubricant to penetrate.
Randers Reb has developed a special lubricating oil, Randers WIRE OIL Type 01, which satisfies the special requirements for lubrication of steel wire ropes. The oil has excellent penetrative and lubrication qualities. It is also water-resistant and contains additives that dissolve rust and prevent further formation of rust during storage and operation. The oil is easily applied with a brush.
See also our Product Information leaflet, “Lubrication and Maintenance of Steel Wire Ropes”.
Inspection of Steel Wire Rope
The following guidelines cover possible points that should be checked in conjunction with the inspection of steel wire rope. This is not a complete manual, nor is it an alternative to the relevant norms and standards.
Wear and Tear
As a rule, a steel wire rope should be replaced when the nominal dimension is reduced with 10%.
Elongation
All steel wire ropes become elongated when loaded (see also “Steel Wire Rope Elongation”, page 8-28). The elongation of a steel wire rope during its lifetime can be divided into three phases:
- Phase 1: The new steel wire rope becomes longer quite naturally during its initial period of use. This partly because of the loading, and partly because the steel wire rope settles.
- Phase 2: When the steel wire rope has settled and for most of its lifetime, the steel wire rope does not become much longer. Elongation during this phase is mainly due to wear.
- Phase 3: The steel wire rope suddenly becomes longer very quickly. This means that the steel wire rope is deteriorating rapidly due to such causes as advanced wear and fatigue. The steel wire rope must be replaced immediately.
Reduction of Dimensions
Every noticeable reduction of the steel wire rope’s dimensions in comparison with its original dimensions indicates a deterioration in the steel wire rope. The reduction may be due to such causes as:
- External/internal wear and tear
- Compression of strands and/or core
- External/internal formation of rust
- Elongation
Rust
Rust is just as important a factor as wear and tear in terms of evaluating the steel wire rope’s condition. Rust is normally caused by poor maintenance of the steel wire rope and promotes quicker fatigue in the wires (fragility/creation of cracks).
Kinks
Kinks cause permanent damage to the steel wire rope. Kinks are formed due to extraction of loops.
The steel wire rope must be replaced immediately.
Bird’s Nest
A “bird’s nest” (the strands rising in the same place) is created by such actions as the steel wire rope being subjected to torsion (rotated), sudden unloading, running through sheaf grooves that are too small and/or winding on a drum that is too small (fig. 44). The steel wire rope must be replaced immediately.
Local Wear and Tear/Damage
Local wear and tear is most often caused by poor winding. All fittings and splicings must also be inspected for wear or broken wires, loose or split strands, wear or cracks in fittings, etc.
Fire Damage
After a fire or exposure to high temperatures, metal damage, loss of oil/grease and destruction of fibre core, etc., may occur.
The steel wire rope must be replaced immediately.
Core Protruding between the Strands
Regardless of the cause of the core protruding between the strands, the steel wire rope must be replaced immediately.
Wire Fracture
A wire fracture may result from many different causes, some serious, others insignificant.
If the wire fractures are serious, the steel wire rope must be replaced immediately. If you are in any doubt as to whether the steel wire rope should be scrapped or not, please contact your local salesman or our Technical Department as soon as possible.
