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ET

Eddy Current Testing (ET) Services

Eddy Current Testing uses electromagnetic induction to detect surface and near-surface flaws in conductive materials.

What is Eddy Current Testing?

Eddy Current Testing (ET/ECT) is an electromagnetic NDT method used to detect surface and near-surface flaws in electrically conductive materials. An alternating current-carrying coil is placed near the test surface, inducing eddy currents in the material. Defects or material property changes alter the eddy current flow, which is detected as changes in the coil impedance.

How ET Works

1

AC coil generates alternating magnetic field

2

Eddy currents are induced in conductive material

3

Defects alter eddy current flow patterns

4

Impedance changes detected and analyzed

Applications of Eddy Current Testing

Tube and heat exchanger inspection
Surface crack detection
Coating thickness measurement
Conductivity measurement
Bolt hole inspection in aerospace
Weld inspection

Advantages

  • No couplant required
  • Fast scanning speed
  • Can inspect through coatings
  • High sensitivity to surface cracks
  • Automated inspection capability
  • No surface preparation needed

Limitations

  • Only works on conductive materials
  • Limited penetration depth
  • Sensitive to lift-off variations
  • Reference standards required
  • Geometry can affect results

Applicable Standards & Codes

ASTM E243
ASTM E376
ASME Section V
ISO 15548
EN 1711
ASTM E2096

Industries Using ET

Aerospace
Power Generation
Oil & Gas
Manufacturing
Automotive

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