Inspection of the steel under a composite repair allows an estimation of the corrosion growth rate. Understanding the condition of the composite repairs and underlying steel means that the risk of ongoing operation is effectively managed, the cost of replacement can be deferred or avoided and production is maintained – a shutdown is not needed.
Interested in a Composite Coatings Inspection? Get in touch with the Sonomatic team today to find out more.
Inspection of steel through coatings such as composite repairs, corrosion protection tapes and subsea insulation, is not possible with standard ultrasonic inspection methods.
In many situations, other inspection techniques such as Pulsed Eddy Current and Radiography cannot achieve the necessary sensitivity or measurement accuracy. To address this requirement, Sonomatic developed Dynamic Response Spectroscopy (DRS); an innovative ultrasonic inspection technique for mapping corrosion through challenging coatings. Low-frequency ultrasound (<1 MHz) penetrates the coating and excites the steel, causing it to vibrate at its natural frequencies.
Using advanced signal processing algorithms, these frequencies are extracted and used to determine the steel wall thickness profile. The thickness measurement accuracy is typically ±0.5 mm.
The DRS technique is also used to evaluate the integrity of coatings, specifically composite repairs. Flaws such as disbondment contain small air pockets which block transmission of the ultrasound into the steel. DRS detects these flaws where the steel response signal is lost. Flaw acceptance criteria and QA test software have been developed by Sonomatic based on Finite Element models.
The next generation MEC™ technique is a fast and reliable method for the detection of corrosion and defects in pipes, pressure vessels, and drums. Applied during the process conditions, the MEC™ technique ideally supports the Non-Intrusive Inspection (NII) strategy.
MEC™ (Magnetic Eddy Current) is the next generation and a further development of the industry proven fast corrosion screening SLOFEC™ technique.
Pulsed Eddy Current (PEC) is a comparative technique whereby advanced processing of the eddy current signal decay and comparison with a reference signal, allows for the determination of the average wall thickness (AWT). This fast screening method allows for the assessment of the general condition of structural steel and is best suited for general corrosion type defects in pipelines.
Sonomatic uses the Lyft Pulsed Eddy Current Array (PECA), a probe that utilises 6 units operating in tandem. Covering a 457mm wide strip, this unit greatly increases productivity and reduces set-up time.
Sonomatic has developed a technique that can be used to inspect the outer sheath and surface or the metal armour bands of flexible pipes, plastics and composites. The technique uses low-power microwaves, which can penetrate semi-conducting materials where other NDT inspections i.e. Ultrasonic or Eddy Current inspections, are ineffective.
The microwaves used in our inspections are completely safe and are no more powerful than those sent and received during a mobile phone call. The technique uses hundreds of frequency points over a wide bandwidth, this maximises the probability of detection. It also allows us to determine the depthwise position and through-thickness extent of defects.
