Eddy Current Testing (ECT, including Eddy Current Array): Tube Inspections for Reliable Heat Exchangers

IRISNDT uses ECT (including Eddy Current Array) to detect pits, corrosion, erosion, cracking, and others, in stainless steels, brass, titanium, Inconel, copper, copper-nickel, and other non-ferrous tubes. This fast, accurate inspection technique has identified the flaws shown below.

INSPECTION PREPARATION
The tubes must be free of obstructions. However, the cleaning required is minimal.

ADVANTAGES

• This technique is fast with up to 4 ft/s pulling speed through tubes.
• Couplants are not needed. Consequently, contaminants are not introduced during the inspection.
• The technique identifies large and small volume pits.
• 100% of the surface of the tubes is inspected, with 360º coverage through the length. All the data is stored for review.

LIMITATIONS

• With a traditional bobbin coil, circumferential cracks can be missed due to no disturbance in the flow of eddy currents.
• Ferromagnetic deposits on the tubes will lead to erroneous assessments.
• The probe needs a minimum 80% fill factor for maximum sensitivity to defects.
• The technique has a ± 10% variance in call accuracy assessments.

Eddy Current Testing (ECT, including Eddy Current Array): Tube Inspections for Reliable Heat Exchangers