How to test the performance of steel wire ropes and riggings

Steel wire ropes and steel wire rope slings are essential lifting and rigging components widely used in industries such as steelmaking, chemicals, transportation, mining, construction, and port operations. Known for their high strength, light weight, and reliable performance, these slings are indispensable for lifting, towing, and load-securing applications.

To ensure long-term safety and performance, regular inspection and testing of steel wire ropes are crucial. This article provides a comprehensive overview of the key testing methods, inspection standards, and best practices to help you evaluate the condition of steel wire ropes and steel wire rope slings.

Why Testing Steel Wire Ropes Is Important

During service, steel wire ropes are exposed to wear, corrosion, bending fatigue, and deformation. Over time, these factors can significantly reduce the rope’s strength and may lead to dangerous failures if left unchecked.

Regular testing helps:

• Detect early signs of damage

• Prevent accidents caused by rope failure

• Extend service life through timely maintenance

• Reduce replacement costs

• Ensure compliance with international safety standards

• Key Tests for Steel Wire Ropes and Steel Wire Rope Slings

1. Visual Inspection

Visual examination is the foundation of wire rope assessment.

Check for:

• Broken wires

• Abrasion and wear

• Corrosion or rust

• Kinking, birdcaging, flattening, or other deformations

• Loose strands or gaps between strands

According to ISO 4309, a rope must be removed from service if the number of broken wires or degree of wear exceeds the allowable range.

2. Diameter Measurement

Accurate diameter measurement helps identify wear, compression, or internal damage.

Best practice:

Always measure at the maximum diameter position of the rope.

Standard requirement:

If the rope diameter is reduced by more than 7% of the nominal diameter, the rope should be discarded.

3. Tensile (Breaking Force) Test

This test evaluates the maximum breaking load of the steel wire rope.

Procedure:

• Cut a sample from the rope

• Clamp both ends using a tensile testing machine

• Apply a steady load until the rope breaks

The measured breaking force must meet or exceed the minimum rated breaking load specified by the manufacturer or the applicable standards.

4. Strand and Wire Testing (Unlay Testing)

For detailed analysis, individual wires from the strands are tested for:

• Bending resistance

• Torsion resistance

• Tensile strength

This helps assess the fatigue resistance and metallurgical quality of the rope.

5. Bending Fatigue Test

This test simulates real-world bending conditions, especially for ropes running over sheaves or drums.

Purpose:

• Evaluate fatigue resistance

• Predict service life in dynamic applications

ISO 2408 specifies the acceptable limits for performance reduction under repeated bending cycles.

6. Non-Destructive Testing (NDT)

Modern NDT methods can reveal internal damage not visible from the outside.

Common techniques include:

• Magnetic flux leakage (MFL) testing

• Ultrasonic testing

• Electromagnetic inspection

NDT is especially important for mining hoist ropes, port cranes, elevators, and offshore applications.

7. Lubrication Condition Check

Proper lubrication reduces friction, prevents corrosion, and slows down wear.

Inspection includes:

• Evaluating lubricant condition

• Checking for dry areas

• Reapplying specialized wire rope grease as needed

Consistent lubrication directly extends the lifespan of steel wire ropes and slings.

International Standards for Steel Wire Rope Testing

ISO Standards

• ISO 4309 – Inspection and discard criteria for steel wire ropes used on cranes

• ISO 2408 – General requirements and technical specifications for steel wire ropes

Industry-Specific Standards

• MT/T 716 – Requirements for mining wire ropes

• Marine, elevator, and offshore industries may apply additional regulations depending on operating environments.

Testing the performance of steel wire ropes and steel wire rope slings is essential for maintaining operational safety, preventing unexpected failures, and ensuring compliance with industry standards. By performing regular visual inspections, diameter measurements, tensile tests, bending fatigue tests, and non-destructive evaluations, operators can detect early signs of damage and take corrective action in time.

A well-structured maintenance and testing program not only protects personnel and equipment but also maximizes the service life of your wire rope assets.