Surface Eddy Current Testing is a specialized electromagnetic inspection technique used to detect surface and near-surface defects in heat exchanger tubes. SECT is particularly effective for identifying cracks, pitting, and surface corrosion that initiate on the tube inner diameter.
This technique is commonly used as a supplementary inspection method where high sensitivity to surface-breaking defects is required.
Why Surface Eddy Current Testing Is Required
Many tube failures originate as small surface defects that grow over time. Surface Eddy Current Testing allows early identification of these defects before they propagate into through-wall failures, improving reliability and safety.
SECT is especially valuable for detecting stress corrosion cracking and localized pitting.
Scope of Inspection
SECT is applicable to:
Non-ferromagnetic heat exchanger tubesStainless steel and alloy tubesTubes susceptible to cracking or surface corrosion
Inspection Methodology
Surface Eddy Current Testing is performed by passing a high-frequency eddy current probe through the tube length. The electromagnetic field generated by the probe is highly sensitive to surface and near-surface discontinuities.
Variations in the eddy current signal caused by cracks, pits, or corrosion are recorded and analysed. Signal patterns are interpreted by trained inspectors to differentiate between defect types and assess severity.
Key Benefits
SECT provides high sensitivity to surface defects, early detection of cracking, rapid inspection of tube bundles, and reliable data for preventive maintenance decisions.
Industries and Applications
SECT is widely applied in refineries, power plants, petrochemical facilities, fertilizer units, and chemical industries operating non-ferrous and alloy heat exchanger tubes.
Surface Eddy Current Testing is a valuable inspection technique for detecting early-stage surface damage in heat exchanger tubes. By identifying defects before they grow, SECT supports safe operation and effective asset management.
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