Wire ropes are common mechanical devices used for supporting or lifting loads in applications such as cranes and pulleys, winches, mooring lines, elevators and suspension bridges. It comprises of continuous wire strands wound around a central core. Each wire strand is made up of two or more wires wound around a center wire.
There is a wide variety of wire ropes for different applications. The most common material for the wires that make up the strands is steel, while the core can be made of steel, rope or even plastics.
Wire Rope Lubrication
The most common failure modes for wire ropes are abrasive wear and corrosion. Individual strands inside the rope move and rub against one another during normal operation, creating internal two-body abrasive wear. External abrasion can also occur as the outside of the cable accumulates dirt and other contaminants from sheaves and drums. This causes three-body abrasive wear, which erodes the outer wires and strands. Corrosion results from an exposure to acids, sulfur, salt, moisture and some gases. It is accelerated by elevated temperatures. Corrosion can cause shortened rope life due to metal loss, pitting and stress risers from pitting.
Therefore, the most important lubricant characteristics are wear resistance and corrosion prevention. Wear resistance is quantified using metrics such as the four-ball standard tests. The salt spray corrosion test (ASTM B117) and copper corrosion tests (ASTM D130) are good indicators of the lubricants ability to resist corrosion.
Another important lubricant characteristic is penetration. Since most wire ropes fail from the inside, the lubricant needs to penetrate to and properly lubricate the rope core. This also helps to reduce internal abrasion between the strands of the rope as they rub against each other. At the same time, the lubricant should also have to ability to coat the rope to seal out contaminants such as moisture and dirt/dust debris.
ROCOL’s BIOGEN WIRESHIELD is a high performance environmentally acceptable lubricant (EAL) specifically optimized for wire rope applications. The BIOGEN WIRESHIELD has excellent corrosion protection and wear resistance properties. It utilizes pseudo plastic rheology technology, which allows it to transform into a fluid consistency under shear. When the shearing stops the BIOGEN WIRESHIELD stiffens back to a grease consistency on standing. This allows the grease to penetrate deep into the core of the rope, while still providing an outer coating which resists dripping, fling and water wash off.
