Introduction

The benefits of lubricating wire rope are well known. This article attempts to explain why lubricant is so important, and also the effects on service life.

Why is lubricant so important?

During operation, wire rope is consistently subject to considerable bending forces. These bending forces make the wires in the rope move against each other, resulting in friction. Additionally, when the wire rope moves against the sheaves, frictional forces also occur. In the interest of enhancing rope life, a lubricant is applied to reduce these frictional forces.

Corrosion protection?

Although some lubricants provide the benefit of improved corrosion protection, the majority of lubricants used to reduce friction provide little advantage in terms of preventing corrosion.

Benefits for Rope Life

In 1966, the wire rope scientist H. Müller performed tests to evaluate the benefit of lubrication on rope life. The results were staggering; Müller showed that lubricated rope performs around five times better than the equivalent without lubrication in terms of achievable bending cycles!

The chart below shows how wire rope capable of achieving 20,000 bending cycles without lubrication can reach 100,000 with it.

In 1977, Müller also showed how, in the case of tensile fatigue, wire ropes have an endurance around a third greater if they are lubricated.

Should we relubricate?

The answer to this question depends mainly on the number of bending cycles you expect the rope to perform.

If a wire rope is expected to be subject to a low number of bending cycles, the lubrication provided by the manufacturer is likely to be enough for the entire rope lifetime. There are some exceptions to this rule, such as when a rope is exposed to a particularly harsh environment.

In cases where a rope is expected to perform a large number of bending cycles, then relubrication will provide a significant benefit.

Poorly performing ropes?

In some cases where a rope is performing poorly, lubrication is the primary cause. Therefore, it is recommended checking the lubrication of the rope and reporting any deficiencies to your supplier.

Another option would be to relubricate the rope yourself. There are many rope lubrication devices on the market that allow you to perform this task quickly and efficiently.

Conclusion

This article has hopefully outlined some of the benefits of lubricating your wire rope. Lubrication remains one of the most important factors with regards to rope lifetime and should be carefully checked to ensure rope performance.

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Thanks for reading,

The Rope IQ team.

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References

Müller, H.: Drahtseile im Kranbau, Auswahl und Betriebsverhalten. VDI- Berichte No. 98 und dhf 12 (1966) 11, pp. 714–716 and 12, pp. 766–773

Müller, H.: Vortrag bei der Jahreshauptversammlung der Drahtseil- Vereinigung am, 1977