Wire ropes are typically critical for plant operation with no redundancy. Following the traditional replacement strategy can be a costly choice with premature replacement and unplanned downtime costs proving monumental.
The smarter strategy is routine inspection and condition monitoring; allowing for the replacement of the assets to be strategically managed, maximising rope lifetime and minimising downtime.
Wire rope MFL is a replacement for the slow process of visual inspection, which is difficult due to lubrication products and inability to detect internal breakages. We utilise the latest Residual Field Magnetic Flux Leakage Technique. Residual Field MFL works through the inspection and analysis of the residual magnetic field of a magnetised ferromagnetic wire rope. Changes in magnetic flux are detected where defects are present in the rope due to a change in cross sectional area (broken wires, corrosion or abrasion) or a change in permeability due to work hardening (fatigue).
Our Equipment is capable of detecting internal and external broken wires, corrosive pitting, abrasion, fatigue, including a summation of the multiple defect types.
Shiploader Wire Rope Inspection
The applications for Residual Field MFL testing are broad. The technology can be used to monitor and assess the condition of dynamic or static wire ropes for stackers, reclaimers, shiploaders, bridges, conveyor uptake towers and more.
MFL inspection goes above and beyond visual inspection by allowing for internal defects to be detected and quantified. Our equipment allows for rapid inspection of up to 3m/s and creates an interpretable report that ensures a permanent record of the rope condition to enable future inspection and replacement strategies to be planned.
Inspection Diagram
ISO4309 recommends that when it is the intention to use electromagnetic means of NDT as an aid to visual examination, the rope should be subject to an initial electromagnetic NDT examination as soon as possible after the rope has been installed.
For subsequent inspections testing frequency should be based on expected rope life operating cycles, operating conditions and rope constructions. AS4812 recommends that frequencies do not exceed one sixth of the expected rope life, with a limit of between 6 and 30 months depending on the type of rope.
Inspection should also be carried out following an incident that could have caused damage to the rope and/or its termination, or if a rope has been brought back into operation after dismantling followed by re-assembly.
• Interference from electromagnetic equipment may interfere with results.
• Inspection is limited to ferromagnetic ropes.
• Inspection of terminations is not possible using MFL due to the presence of magnetic poles.
• The equipment used must suit and be calibrated to the diameter range being examined.
• Sensitivity decreases for smaller diameter ropes.
Please contact ARI to discuss strategies for reducing the limitations of Residual Field MFL.
Pendant Socket Visual Inspection
As a guide, for a decrease in actual rope diameter greater than 3% for rotation resistant ropes or 10% for non-rotation resistant the rope shall be discarded even if no broken wires are visible.
Contact us for further discard criteria or refer to ISO4309
Wire Rope Flaw
ARI has a set of wire ropes in our workshop with flaws of known size built in.
This enables us to verify that our calibration is accurate.
Verification Rope
Inspectors using Residual Field MFL should be trained and certified by the manufacturer or a certified agency.
As best practice we sent our degree qualified engineers overseas to receive manufacturer training, examination and certification.
By using non-wire rope supplying service providers to assist with your Wire Rope Inspection needs you will avoid any conflict of interest.
ARI Personnel
Specialists In Wire Rope Inspection
