INTRODUCTION TO LUBRICATION OF WIRE ROPE
Proper lubrication of wire rope, or steel cable, is essential for two reasons. The first one is safety. Wire ropes that are improperly lubricated are far more prone to both interior and exterior wear, and as such are at greater risk for failing. A wire rope that breaks while being used can cause great injury or death, since they are often a critical piece in hoisting, towing, dragging, braking, or similar operations.
The second reason is simple economics. A wire rope that is well maintained and lubricated will last far longer than one that isn’t. Life of a wire rope can be extended several times if properly lubricated.
Wire rope bending around hoist drums and sheaves will wear like any other piece of metal, so you should lubricate wire rope the same as any other piece of working machinery. Wires and strands of a rope must be able to move freely in order for the rope to function correctly. Corrosion from moisture or wear due to friction shortens the service life of wire rope.
Wire rope should always be well cleaned before lubricating. Scraping, steaming, or high-pressure washing may remove most of the dirt and grit that has accumulated on used wire rope. Rust should be removed on a regular basis with a wire brush. The purpose of cleaning is to remove all foreign material and old lubricant from the valleys between the strands, as well as the spaces between the outer wires. Otherwise, new lubricant will not be able to flow into the rope.
Of the two, corrosion is more dangerous than wear because corrosion ruins the interior of a rope. This is very difficult to determine by visual inspection.
Exterior deterioration caused by wear is much easier to spot. Outside wires become flattened and reduced in diameter as the wire rope wears.
Both internal and external lubrication protects a wire rope against wear and corrosion.
Abrasion or reverse and sharp bends cause individual wires to break and bend back. These breaks are known as fishhooks. Wire rope should be examined carefully for fishhooks, kinks, and worn and corroded spots. Breaks in individual wires will usually occur in areas where the wire runs continually over the sheaves or bend onto the drum. This is also a good place to look for problems, because the strands may separate slightly as the rope passes over, thus allowing slightly better examination.
There are two conditions that will usually reduce the diameter of a wire rope: Overloading, and failure to lubricate. Rope that is 75 percent of its original diameter should be removed from service. When pitting and corrosion of the wires are visible on the surface, you should assume that the same problem exists internally, and the rope should be removed from service.
Special care should be taken to examine the valleys and small spaces between the strands for rust and corrosion. Since corrosion is normally caused by insufficient or nonexistent lubrication, if you see external corrosion, assume that the internal wires of the rope are being damaged by extreme friction and wear at the same time. This type of internal and often invisible destruction of the wires is one of the most frequent causes of unexpected and sudden wire rope failure. To prevent this, keep the rope well lubricated, and handle and store it properly.
Wire rope should never be stored in an area where acid is or has been kept. This must be stressed to all personnel. The slightest trace of acid or acid fumes coming in contact with wire rope will damage it at the contact spot. Wire that has given way has been found many times to be acid damaged.
It is extremely important that wire rope be cleaned and lubricated properly before placing it in storage. Fortunately, corrosion of wire rope can be virtually eliminated if lubricant is applied properly and sufficient protection from the weather is provided. Remember that rust, corrosion of wires, and deterioration of the fiber core will significantly reduce the strength of wire rope.
INTERFLON WIRE ROPE LUBRICANT RECOMMENDATIONS
Fin Super with MicPol: Suitable for above-water applications. A spray lubricant that goes on wet and dries to a solid film that protects from wear and moisture. Also has outstanding penetrating and creeping abilities, so it can quickly work its way throughout a wire rope and lubricate both interior and exterior.
Lube EP with MicPol: Similar to Fin Super but formulated to withstand extreme pressure.
Food Lube with MicPol: Again similar to Fin Super, but is rated NSF H1 and certified kosher and halal for use in the production of food, beverages, pharmaceuticals, cosmetics, or animal feed.
Fin Grease with MicPol: Again similar to Fin Super, except that upon application from the aerosol can, it expands to a grease instead of remaining a liquid. Suitable for applications where a more viscous solution is required.
Grease OG with MicPol: A grease with excellent metal adhesion that strongly resists washout and can withstand a temperature range of -20 C to 120 C. Ideal for use on outdoor and underwater cables, as well as heavily loaded open drive mechanisms such as turntables on cranes, bridges, locks, etc. Can be used with pneumatic lubricant spraying system. Calcium lithium complex grease with a DN factor of 60,000.
In general, you should plan on applying approximately 5 liters of lubricant for every 100 meters of 35-mm diameter cable.
For salt water applications, consider the use of a system that will force Grease OG into the rope. One example of this is the Viper system.