1. Basics of Wire Rope
Lubrication
(2% of wire rope weight should be comprised of the lubricant and
more details hereunder)
Wire rope lubrication serves two basic functions:
1. To reduce friction as individual strands (wires) move over each other, and
lubricate the core;
2. To provide corrosion protection; prevent moisture and dust entry and wear
protection from rubbing with external bodies during operation.
Wire rope lubricants are of two types: penetrating and coating. Penetrating lubricant
contain a solvent that carries the lubricant into the core and then evaporates leaving behind a lubricating film to lubricate the core and
individual strands. Coating lubricants penetrate slightly, sealing the outside of the rope from moisture, reducing wear and fretting
corrosion from contact with external bodies.
Most wire ropes fail from inside. It is important to make sure that the center core receives sufficient lubricant. Hence a penetrating
type lubricant is must. Coating (asphaltic) type lubricant may be used as supplementary. Wire ropes are lubricated during the
manufacturing process. Relubrication is required from time to time due to loss of the original lubricant from loading, bending and
stretching of the rope. Relubrication is necessary to minimize corrosion, protect and preserve the rope core and wires, and thus extend
the service life of the wire rope.
Benefits of wire rope lubrication: Abrasive wear occurs on the inside and outside of wire ropes. Individual strands inside the rope
move and rub against one another during normal operation, creating internal two-body abrasive wear. The outside of the cable
accumulates dirt and contaminants from sheaves and drums. This causes three-body abrasive wear, which erodes the outer wires and
strands. Abrasive wear usually reduces rope diameter and can result in core failure and internal wire breakage. Penetrating wire rope
lubricants reduce abrasive wear inside the rope and also wash off the external surfaces to remove contaminants and dirt. Years of field
experience shows that longer wire rope life can be obtained through the use of penetrating lubricants, either alone or when used in
conjunction with a coating lubricant. Practical experience at a South African mine suggests that life cycles may be doubled with this
approach. At one mine site, the replacement rate for four 44-mm ropes was extended from an average 18.5 months to 43 months. At
another mine, life cycles of four 43-mm x 2073 meter ropes were extended from an average 8 months to 12 months. (Data from
Machinery Lubrication Magazine, July 2002. (www.machinerylubrication.com)
Properties of a good penetrating type lubricant: 1. Contains solvent for easy penetration between adjacent wires in order to lubricate
and protect them against wear and to keep the rope core from drying out; 2. Adhesive, does not get “fling off” during bending, loading,
stretching during operation; 3. High load carrying capacity; 4. Good corrosion protection against rusting by acids, alkalis or salt water;
5. Resist softening or thinning out to the extent that throw-off or drippage occurs at high temperatures at which rope will operate; 6.
Resist being washed off by water; 7. Form non-sticky films so that dust and dirt will not build up on ropes; 8. Be suitable for
application by brush, drip feed, spraying, pouring on a running section of the rope, and running the rope through a trough or bath of
lubricant.
Molykote® technologies available for wire rope lubrication:
1. Molykote® 3694 Wire Rope and Open Gear Grease: Penetrating type grease with solvent, with complete resistance to
water available in 1 kg packs for brushing onto wire ropes. Four ball load 3600N, AWM 15000N. Provides exceptional
adherence, corrosion protection and maximum continuous resistance to extreme pressures and shock loading. Contains
molybdenum disulphide for wear protection of individual strands and works well upto 130 deg C.
2. Molykote® S-1004/1014 Open Gear and Wire Rope Spray: Semi-synthetic open gear and wire rope in spray cans with
excellent adhesion, high load carrying capacity and good water and moisture resistance. 535 mm2/s viscosity at 40 deg C
form a thick lubricating film separating metal surfaces. Four ball load 6000N. Service temperature upto 150 deg C.
Other Molykote® products that can be used for wire ropes: Underwater wire ropes (Molykote® P40 paste), Multiple application
product for wire ropes, chains and open gears (Molykote® 1122 Synthetic Grease spray), semi-fluid 00 consistency adhesive grease
(Molykote® Long-term 00), completely dry anti-friction coating for dusty environments (Molykote® 321R AF Coating Spray/bulk
form).
Molykote® is a registered trademark of Dow Corning Corporation. Molykote® extends equipment life, simplifies yours.
When you need to be absolutely sure, trust Molykote®. Call Project Sales Corp, 28 Founta Plaza, Suryabagh,
Visakhapatnam 530020, AP. at 0891 2564393, 5566482 or fax us on 0891 2590482. mailto:satish@projectsalescorp.com