Guidance on proper storage, lubrication, and discard of crane ropes

Usha Martin’s specially designed high-performance wire ropes are one of the most crucial components in heavy-duty cranes, without which the cranes can’t function at all. Our wire rope ensures a longer operational life and minimises downtime costs. Proper storage, installation, maintenance, lubrication, and discard of wire rope needs to be carried out as per international standard ISO 4309 to extract the maximum life from our products. 

Proper Storage of wire ropes

Storage

• Ropes should be stored in a cool, dry building and should not be allowed to be in contact with the floor. They should not be stored where they are likely to be affected by chemicals, chemical fumes, steam, or other corrosive agents. Ropes should be covered so that moisture cannot induce corrosion in ropes.
• Ropes in storage shall be checked periodically for any signs of deterioration such as surface corrosion and, if deemed necessary by a competent person, dressed with a suitable preservative or lubricant which is compatible with the rope manufacturing lubricant.
• In warm environments, the reel shall be periodically rotated one half-turn to prevent drainage of lubricant from the rope.

Wire rope lubrication

A wire rope is a piece of machinery with many moving parts (wires-strands) and as such it is subjected to internal and external friction causing wear and corrosion.

Suitable lubricants are applied during the manufacturing of the core, the strands, and finally the finished ropes. The service lubricant should be compatible with the original lubricant used by the wire rope company.

A good lubricant must have the following properties:

• Good adherence
• Resistance to penetration of water and other corrosive elements
• Antioxidants - to resist ageing
• Alkaline-based emulsifiers - to neutralize acid
  
  

Rope lubrication during manufacturing:

• Petroleum base lubricant
• Bitumen base lubricant

Basic discard criteria of wire ropes

• Evidence of plastic wear or surface embrittlement on outer wires
• Sudden reduction in diameter with increased lay length
• Severe corrosion like chain pitting or internal corrosion
• Distortions like kinking, crushing, birdcaging, etc.
• Evidence of core-collapse or damage through heat
• Severe shock load or overload due to some accident with equipment
• End fitting/attachment damaged, cracked, deformed, or worn-out
  
  

Broken wires

• Crane ropes must be considered for discard if the number of visible broken wires equals or exceeds the allowable limit.
• Wire breaks in the strand valley indicate internal rope deterioration and require closer inspection of the rope. It should be considered for discard if there are two or more such breaks in a length of rope equal to 6 x d.
• Broken wires adjacent to the termination, require the termination to be remade by shortening the rope, otherwise, the rope should be discarded.
• Complete fracture of one strand or collapse of core requires immediate discard of wire rope.

Increase in rope diameter: This characteristic is often related to a change in the condition of the core, such as a fibre core swelling up due to the absorption of moisture or the accumulation of corrosion debris within the rope.

If the rope diameter increases by 5 % or more in a rope with a steel core or 10 % or more in a rope with fibre core during service, the reason for this shall be investigated and consideration is given to discarding the rope.

Decrease in rope diameter: A decrease in rope diameter can result from a number of factors, one of which is external wear. Usually results from contact with sheaves or drums or from the pressure of rope on the rope, as would be expected at the cross-over zones as the rope traverses the drum. More pronounced amounts of wear are usually found in those sections of rope which are in contact with the grooves of sheaves and drums when the load is being accelerated or decelerated. A lack of lubrication and the presence of abrasive dust can also affect the rate of wear. In addition to the obvious visible mode of deterioration described above, the rope can also decrease as a result of one or a number of internal mechanisms, such as:

• Internal wear is caused by friction between adjacent strands and wires in the rope, particularly when it is subjected to bending.
• Deterioration of a fibre core or fracture of a steel core.
• Fracture of the inner layers of strands of a rotation-resistant rope. By reducing the metallic cross-sectional area of the rope by wear, the strength of the rope is reduced.
  
  

Conclusion: We at Usha Martin are committed to working together with our customers to extract the optimum life cycle from our wire ropes. Therefore, proper storage, handling & installation of wire rope is crucial. Thus, being one of the leading wire rope manufacturers, we follow international standards as per ISO 4309 in helping our end-users to achieve maximum performance from our products.